Newstips Bulletin Special Reports
The Newstips Bulletin is a more than 35-year-old weekly bulletin service that only working press can qualify to receive; it's the core publication from which we draw the information and product reviews that we present to 6.5 million radio listeners as regular participants on 5 significant radio programs. The Bulletin itself has a “secret recipe” that its many longstanding readers appreciate: no item is ever longer than a single paragraph.
Each issue includes a Special Report, essentially self-contained briefings on a topic that we feel will interest our readers.
We confess to a weakness for puns and gimmicks in our headlines so wile we include a list of the headlines here as jumps to the items below, we suggest reading a few for a sense of flavor, then perhaps all, one time through, so on future visits, the jumps can take you directly to items of specific interest. The very long section with the full items is separated by headings identifying the month and year the coverage ran; since not every special report was on a topic relevant to this project, some months include more items than others.
We should alert you: this is an extremely long page. The list of headlines below will jump you to its item. This is, alas, the best approach we could come up with. The items are listed in the chronological order of their publication.
Our editorial house project calls for coming as close as possible to 40-years-maintenance-free while doing everything possible to moderate energy consumption; refrigerators & freezers are unlikely to survive for that period & we were able to get a briefing from a former category brand executive who now runs a high-end appliance store. Standalone refrigerator/freezers (like those you see at Best Buy, Home Depot, Lowe's, etc.) don't have separate evaporators & compressors for their refrigerator & freezer sections, their door designs tend to allow a higher variation in inside temperatures & they are rarely more than about 6’ tall. Built-in 7’-tall “column” units (one column per refrigerator, one per freezer) place a separate compressor & evaporator in each column, tend to come in a limited number of standard widths, tend to be less deep than standalone models & tend not to have glamorous through-door features. They also tend to offer much tighter control over internal temperatures with very good husbandry of their energy consumption. One result of that is the potential, with better units & a little luck, to reach 18 years without requiring major maintenance. Ironically it isn't maintenance that compels most replacements but changes in Federal requirements for refrigerants; given that, built-in columns seem to represent the sweet spot in getting all the life expectancy you're allowed to have while reducing maintenance costs & enhancing energy efficiency.
The odds are overwhelming that your dwelling's outer walls involve wooden stud framing, rolls of insulating material & perhaps blown-in foam, a very traditional construction meme that has become notorious for its inefficiencies. Radiant heating of outer walls conductively crosses the thermal bridge of the wooden studs, bringing heat to the interior (or, when cold outside, allowing it to escape). Insulating materials within the wall are not tightly fit, allowing airflow around them. Structural insulated panels (SIPs) are a newer & much more efficient alternative; these are a laminated sandwich of an expanded polystyrene foam (EPF) core between sheets of oriented strand board (OSB). The OSB is a manufactured board (from Huber, Weyerhaeuser, et al) with pressure-matted 4” squares of woodgrain in pseudo-random orientation; the result is stronger than studs for structural support. SIPs are manufactured in 8’x24’ panels, custom cut to a builder's requirements, precut for door & window framing & prepared with runways for electrical outlets, switches & wiring runs. 3 energy benefits result: better air containment through insulation continuity with no accidental gaps or flow paths as there might be with roll or mat insulation… no thermal bridging through studs… & no vertical convective looping. EPA tests at Oak Ridge National Laboratory show the SIP structure to be 15 times more air-tight than traditional stud-based construction.
As we investigate the sensors available as smart home products in comparison to those available at large we find noteworthy gaps. Decades ago, electronic distance measurement took a giant leap when Polaroid embedded an ultrasonic rangefinder in a camera; we don't see similar sensors in the home automation catalogs but inexpensive modules are readily available. Distance measurements from modules on a garage ceiling could tell whether a garage door is opened or closed & whether or not a garage space has a car in it; if on the back wall opposite the garage door, it could again detect the presence or absence of a car, know when a car is entering or leaving that garage space & trigger a stop-now signal when the car reaches its ideal position. Photoelectric beam-break sensor pairs (also not seeing these as home automation category products) can identify both the presence & direction of people entering or leaving rooms; simple “abacus” logic could then determine the current population of the room as a trigger for controlling lights, HVAC settings & ventilation dampers or for a front-door display of where occupants are if a fire is detected. Some of the newer tech we see as promising includes using the time-of-flight of light to measure distance, RF field disturbance whole-structure mapping (able to image inside & through walls), low-resolution heat cameras that can isolate people & pets & unexpected heat sources from expected heat backgrounds & clamp-on inductive current monitors able to identify when things like HVAC systems or refrigerators draw more current than usual, a sign of either a shift in load (time to change the filters or refrigerant, check the belts & compressors) or the early stages of a failure.
Whenever the idea of creating a residence in a Dewar flask (Thermos bottle) by insulating it from its surrounding environment arises (as in our earlier reports on advanced walls & roofs), it brings dramatic reductions in overall energy usage & costs. One way is to block the thermal bridges that conductively connect a structure's exterior to its interior; direct radiant heat is a major factor there but less so for the underside of a structure. For any structure built not on a slab but over a basement or crawl space, Insulating Concrete Forms (ICF) sandwich dense structural concrete walls inside insulating foam liners, inside & out. The foam provides a gap-free, zero-porosity, high-R-value thick skin around the high thermal mass of reinforced concrete. We've seen data showing ICF walls delivering 2¾ times the strength at ¾ the cost & half the build time of conventional foundation walls.
Automation first arrived for home comfort systems when furnaces got the first thermostats. In a modern house, comfort sources may include an HVAC system, a whole-house humidifier, a fireplace & ceiling fans. In an autonomous house, add motorized flow-control shutters at every duct or register plus monitoring in every room for at least temperature, humidity and occupancy. If an intelligent control system replaces the thermostat, the logical framework may look like this: Each room gets assigned a Delta (change) value based on how long it's been unoccupied; the longer the vacancy, the larger the Delta value. Occupants enter a desired comfort level temperature for the house at a panel that looks like a contemporary thermostat but which has no direct control over heating or cooling systems. The controller determines whether current temperatures in any of the rooms differs by more than the Delta from the desired setting & only then turns on the HVAC fan & heating or cooling, as appropriate. The circulation to vacant rooms gets moderated by the shutters, tuned through adjustments made any time it's the reading from a vacant room that triggers the use of the HVAC system. Similarly, control decisions to use the fireplace are based on time of day & a whether or not an occupant is or soon will be in the space it warms; vent shutters in that space get trimmed back as the fireplace warms the room. While this is a simplification, it demonstrates how automation principles may be applied to home heating, cooling, humidification & ventilation systems to deliver more in-home comfort with less overall energy usage & cost.
Ceiling fans on screened porches are not uncommon even in Northerly climes while it's very common indeed to see one or more ceiling fans above a lanai or front porch in warmer parts of the country. Many have simple on/off controls & some offer multiple speed choices; in the design of automation for such fans, the first consideration must be as to their true purpose & their actual deliverables. Fans provide cooling by providing air flow that promotes evaporation on the skin & for every fan, that's an effect that sooner or later decreases with distance. Such fans have no reason to be running when nobody's there, so human presence detection is one of the conditions for operation. Temperature is a second consideration; too cold & a fan adds to discomfort while in an already temperate range a slow fan speed tends to be more pleasant than a faster speed. Humidity is also a factor; high humidity slows evaporation & calls for an increase in fan speed. One forgotten factor is wind speed; if the breezes are is already moving as much air as the fan could move, operating the fan becomes unnecessary. Elsewhere in an autonomous house, wind speeds may also play a role in decisions about lawn watering or in the extension of motorized awnings, for example.
A fire chief friend of ours, in sharing the following, remarks, it “only took thirty years to figure this out”: the term is flow path control & it refers to closing off or limiting outside ventilation when attacking fires. Even in tight houses where a fire has not vented itself (burnt through to the outside), leaving the HVAC on will significantly assist the fire's spread throughout the structure. If there is control available over duct flow, it also helps to shut those down. These measures help the fire choke itself out by initially consuming then starving for oxygen. During structure fires, firefighters also try to shut down utilities to avoid electrocution, avoid shorted wires creating new high-temperature ignition sources & avoid allowing gas lines to further fuel the flames. In an autonomous house, this suggests a total shut-down of all HVAC fans, all ceiling fans, all pressure-equalizing fans, all vent fans & full shuttering of all ducts. In the new construction of a house, it also suggests conduit (some plastics may have advantages) for all wiring rather than simply running jacketed electrical cabling.
By far, most heat-vision devices are not visual; they are single-pixel detectors that measure temperatures, including specific temperature ranges, like the PIR (passive infrared) motion sensors used in security or lighting control or hands-free faucet applications, for example. Some PIR vendors (notably Panasonic & Omron) developed small arrays & improved the tech to also detect non-moving bodies. Actual heat vision cameras & smart phone adapters (notably from Flir & Seek Thermal) dropped the price of viewing thermal video to consumer levels. Historically, the segment has been popular with hunters & tactical shooters as well as with building & remodeling trades with an interest in monitoring structures for heat leaks. At consumer prices, such devices are beginning to find new uses, like seeing where pets or feral animals may be in a yard, inspecting walls for telltale signs of electrical or plumbing issues or even profiling a grill for hotter versus cooler cooking spots.
Consider running a duct from a computer CPU fan to a case side vent; while you gain the benefit of directing all of the blow past other components, that duct can also heat up & radiate that heat to other components; either choice adds heat to the motherboard. If you could install a double-wall insulated duct (we don't know of any available for PCs but they may exist) you improve CPU cooling & reduce motherboard heating. Most residential ductwork is either a single-wall tube or a plastic counterpart; these add the least cost to a build. Up a significant tier is a double-wall insulated duct; the top tier adds an antimicrobial coating; the cost of these tends to limit their use to commercial buildings or mansions. The physics of double-wall ductwork offer multiple benefits. The double wall affords some acoustic isolation, reducing HVAC motor & wind noise. Thermal delivery is, of course, improved, since the duct is not exchanging heat along its run & the more efficient delivery of its heating or cooling flow to the room register at its far end also means a reduction in the energy needed to bring that room to its target temperature.
From what we've been able to learn, there are only 2 reasons not to run household wiring through conduit: one is the cost of the conduit, the other the cost of the labor to install the conduit & feed the wires through. Indoors, steel conduit provides grounding (generally a higher-current grounding path than ground wires in cabling can handle), shielding, some level of protection in a fire, extremely long service life & protection from accidental contact by nails or screws inserted into a wall. Electrical metal tubing (EMT) is a relatively thin-walled steel conduit appropriate for residential purposes; commercial or industrial use may require the thicker walls of other conduit types. In outdoor underground (trenched) applications, PVC conduit has a greater chance of surviving long periods of exposure to wet soil while resisting the stresses of underground installation. We believe that Low-Voltage DC & signal runs also benefit from being in conduit other than the conduit carrying AC power runs.
There's almost nowhere in a modern home that makes traditional insulation approaches, like rolls of fluff, anything but a handicapped solution. When thermally separating a home from the crawl space or basement or foundation below the floor or the attic above, or isolating the attic from the roof, the best current solutions involve spray polyurethane foam (SPF) applied between the trusses & joists. SPF choices involve 2 categories. Lower-density open-cell foams require thicker applications to reach adequate insulation R-values. Closed-cell foams are denser, fill voids better, provide superior R-values with just 3” to, max, 5” depths, age better (R value improves & no outgassing) & are easier to apply. If there's a best-choice closed-cell SPF it may be Foamsulate 220, with higher-end resins, an improved blowing agent for a slightly higher R value, better application yields & it's easier for installers to apply. The trade-off for consumers could be the extra cost of the product versus a need for less product & fewer hours for installers in the short term & additional energy cost savings in the longer term.
For places not served by sewers, the contemporary classic alternative is a septic system: a big, buried concrete tank lets solids settle while normal bacterial action transforms the settled solids into a sludge while liquids get piped out to a leach field where they are eventually absorbed into the soil. Newer alternatives improve on this by deviating from that norm. Buried polymer tanks (by Infiltrator et al) can last much longer than concrete tanks, in part because a cylindrical geometry helps reduce the stresses that may crack the flat, square walls of concrete tanks. Adding tech can both accelerate & improve the bacterial “digestion” of waste. A system from Bio-Microbics, for example, uses an external pump to introduce air into the liquid inside the tank & create a fountain spray that induces more aggressive bacterial growth on fins below. As a result, liquid effluent from the tank is considerably cleaner & sludge accumulates at the bottom of the tank at a slower pace. Over time, of course, all septic tanks need to be pumped out by professional services.
The lowest tier of home construction embeds a lesson in physics. Below any slab, crawl space or basement foundation lies a pattern of footings & piers. Footings tend to be rebar-reinforced concrete square forms over bore holes so the concrete pour creates a claw for added stability. Where walls are inches wide, footings tend to be a foot or more wide. The top level of the footing is below the underside of the slab or basement or crawl-space floor. Some footings may support piers, which are upright struts that connect to the undersides of flooring joists. The job of footings is to spread downward pressure on the foundation away from focal points or lines to prevent cracking; the job of piers is to help support more of the load of the house so it all doesn't come to bear on the exterior frame. When a house has exceptional load points (like the ton of attic water tank in our editorial project house, or the half ton of cabinet electronics in its over-garage bonus room), they have to become part of the decision on footing & pier placement. If you've ever seen a scaffolding sag when, during a presentation of Die Valkyrie, a line of lightness-challenged singers climbs aboard, you have a fair sense of the spread of stresses across a house's frame & through the frame to its foundation.
Consumer household applications for drones rarely go beyond recreation but improving capabilities make them a practical choice for many more-productive activities. With drone models that include downward-facing cameras & programmable waypoints, for example, a drone can patrol a gutter line to show where accumulations may be blocking flows; in so doing, it can reduce the number of potentially hazardous ladder climbs for the homeowner. A similarly equipped drone with sufficient flying time (especially on larger lots) could be programmed with waypoints that let it patrol just inside the property line so, after a storm, it can spot downed trees or ponding (water accumulations) or flooding. A drone with a “follow me” mode could offer a different perspective in capturing family activities on video. A drone can monitor children waiting for the school bus near the street. Drones are not silent, so they may also be useful for urging animal pests to go elsewhere. Consumer drones are allowed to fly at altitudes up to 400 feet & new models have 4K cameras; from that height, they may present invasion-of-privacy concerns for neighbors if inappropriately used; again, since they are not silent, prudence may be the only preventative for squabbles.
In a technical context, latency refers to delays between events, or in communicating an event. For example, a zero-latency sensor sending a signal across the enormous span of a light-year at fully the speed of light will see a year of latency before that signal is read; the same thing happens over shorter distances involving lesser times & there are no zero-latency sensors. In the context of low power wireless automation protocols, two of the factors that allow low-power operation are occasional (not full-time) polling & limited bandwidth, a combination that of necessity means some small delays (latency) in data collection. If you try to run 4K video over a protocol like Zigbee or Z-Wave, for example, you could end up dealing with minutes per frame instead of frames per second; you would also accelerate power consumption. Designs for sensor-rich environments are best served by using line-derived power with batteries as only backups & by designing sensors (as well as controller responses) that are compatible with some sensor latency running as long as full seconds. Such latency depends on the granularity (or bit depth) of the data, the data rate of change & the criticality of the application.
The most sophisticated flame sensors in modern fire prevention systems are electro-optical devices derived from defense systems used to detect missile firing, multi-spectral sensors that look for combined visual, long IR, short IR & UV flame signatures. Some of the oldest flame detectors are mechanical, some using bimetal (like thermostat springs), glass “doorstop” capsules designed to burst (from the vapor pressure of a liquid inside boiling) at a known temperature, or solder-like bonds designed to melt at a specified temperature. Most residential heat triggers are set for 135-170°F, some at 194°F; the autoignition temperatures for most household non-liquid materials are well over 300°F. Some electronic sensors respond to the measured temperature & some to the rate of rise of temperature. Consumer smoke or fire detectors may be unreliable even in familiar environments like attics or garages because of ambient atmospheres. These consumer products tend to be based on either or both of 2 technologies: Photoelectric, in which airborne particulates in a dark chamber reflect a light source as a trigger to detection; or ionization, in which a slam radioactive charge establishes a small current flow between electrodes that is altered in the presence of airborne particulates.
Electronics that can sense, for example, whether there's an obstacle in your path or whether you can fit through an opening have taken many forms, perhaps most famously radar, the first time-of-flight technology, since adapted to sonar & SODAR & more recently to Lidar. Each of these is a range-measuring sensor. There are also simpler object-presence sensors with visible or infrared light emitters (usually pulsed) facing in the same direction as IR or photodetectors; these are in wide use in production line monitoring, generally working over shorter ranges. A few technologies that can sense objects, like RF field disturbance or capacitive sensors, are not currently well-suited in whisker applications. Consider the blades of a ceiling fan stopping inconveniently in the path of a ceiling-mounted IR array (temperature mapping) sensor, for example; a “whisker” can determine whether it's in that unwanted position & micro-pulse the fan motor to move it; the Sharp GP2Y0A02YK0F is one way to accomplish that. In lieu of a whisker, some industrial designs calculate undesirable stop positions & use magnet-magnetic sensors pairs to identify them. Whisker sensing is improving, in large part through the contributions of robot hobbyists.
Some vendors use the not-inappropriate term fabric when referring to their sensing & control systems for commercial & some residential automation, but today's overall challenge is that there are many such patches of fabric that remain detached from one another. In a distributed processing context, the optimum approach may be to make end-points & mid-points both more intelligent & abler to coordinate; this is the nature of a hierarchical system. A practical approach to weaving the patches of fabric into a metaphorical quilt could readily happen with Raspberry Pi elements that can each gather, analyze & report a result from aggregations of assigned information, allowing yet another, modestly powered Raspberry Pi to act as ringmaster. While communications between fabric patches & their sensors will often happen relatively slowly (to conserve power & bandwidth), communication among these mid-point controllers can enjoy a full Ethernet bandwidth. This architecture also makes future shifts in elements of such a needle/thread-integrated system more manageable.
In technology, a mezzanine is an in-between measure to help variations at more than one level all work with each other in a defined way. In “Wild West” or “Tower of Babel” corners of technology, as we currently see in home automation & elsewhere, absent a single standard, a mezzanine affords an opportunity to provide the separate players, protocols & patois a central message exchange. In practical terms, a common trend among many of the differing players is IP connections, directly or through hardware (hubs, routers, bridges, etc.); if they have a published API, Python code running JSON requests can collect & aggregate everything as if it was all a single, integrated system. In a sense, this is what happens using IFTTT (“if this then that”) online facility with which many devices are compatible. The comparative benefits of a local facilitator for that (like a Raspberry Pi) include increased security, increased flexibility & greater intelligence; the trade-off is that IFTTT offers greater simplicity & requires no significant programming skills.
Ultrasonic echolocation (as in SONAR, SODAR & many consumer gizmos since Polaroid's auto-focus camera) emits a burst of sound, listens for its returning echo, uses its time of flight to calculate the path length & may use changes in that to determine speed & direction. We've been looking at an inexpensive ($2-$10) Cytron board that's popular in hobby robotics. Its maximum range is 400cm, meaning a path length of 800cm; the nominal speed of sound is 340m/sec. Determining there is no obstacle takes the longest, always less than 40msec. The greatest sensitivity has a 30° beam spread; at maximum range the beam spread is 7 feet, give or take. Our project garage, deeper than most, measures 28 feet to the back wall; our cars are 14.6 feet long, bumper to bumper. In this circumstance, ultrasonics from the back wall are less likely to be reliable than ultrasonics on the ceiling when it comes to tasks like detecting whether the garage door is open or closed, whether or not there's a car in its space, whether or not it has pulled far enough forward to clear the door & whether it's coming or going. That may take several sensor heads to separately detect, but with an overall ability of completing 25 readings per second, 5 sensor heads can all take turns without mutually interfering & still each provide 5 readings per second; that, too, is all in the math.
Almost everyone at least once backs into a garage door that isn't open; almost everyone accidentally or absent-mindedly leaves a garage door open overnight or when away. Generally, nothing bad happens, but opportunists often do take advantage of temporary vulnerabilities to safety & security. Garage doors can't open themselves when there's a running car inside without some way to know the car is running. A door can't close itself just because a garage space is occupied (not that it has any way of knowing whether that space is occupied) because, again, it has no way of knowing for certain that the car is not running. These are not major challenges for a controller (the smallest & least capable Raspberry Pi can easily handle the logic); the challenge is in having the in situ intelligence (in this context, simply the information) to recognize the state of the garage door, the status of the garage space & whether or not, for certain, the car's engine running. In the relatively uncontrolled environment of a garage space, thermal measurements are not useful. Ultrasonic ranging or Lidar, cleverly applied, can identify the status of the door and the space. The ostensibly greatest challenge is in identifying whether or not the car is running. A flip-flop of Bluetooth beacon deployment (where the receiver is at a fixed point, in the garage, while the transmitter is mobile, in the car) can solve this if the Bluetooth beacon is wired into the car in such a way that it is only active when the car is running. It's easy enough for future cars to build in BLE beacon features (also usable in other ways) & for garage door openers to build in beacon receivers. In that era, the in-car garage door remote becomes unnecessary & beacon receivers in places like entry gates or office parking lots can also simplify entry for specific, recognized vehicles.
When lighting was done with candles, they rose from tabletops or floor stands or hung from chandeliers or lived in wall sconces. Gas lighting, when it arrived, favored walls. Electric lighting sometimes recessed into ceiling cans or fluorescent bays but mostly, like candles, rose from tables or floors in lamp housings or dropped down from the ceiling. The traditional stalactites & stalagmites of lighting represent interruptions to an occupant's visual field; while we are all accustomed to them, that does not make them desirable. The first phase of LED lighting involved bubs to replace other lighting technologies in their self-same sockets. The second phase is about fixtures, but this phase began by simply removing the sockets and creating largely lookalike lights absent any replaceable bulbs. By next year, we will see fixtures evolve into their own, with configurations & optical paths that direct their light to ceilings & possibly walls, creating a soft but bright glow with the actual emitters never within the line of sight of occupants. The effect will be subtle, usefully bright & gorgeous, appropriate for both residential & commercial applications.
Those now-familiar LED light bulbs that screw directly into AC-powered sockets have their own drivers inside, so well hidden that most of the public has no awareness of the needs for drivers in LED lighting. The most basic of drivers simply converts the AC line Voltage to whatever the bulb or fixture requires (a lower DC Voltage, usually a constant Voltage, sometimes a constant current) & when power to the driver turns on or off, that turns the light on or off. Dimming introduces an additional factor & no single standard governs it. Some approaches use PWM (pulse width modulation), some reduce the current fed to the emitters & many use a 0-10V standard (the control Voltage falls within that range, with 0V indicating full-off & 10V indicating full brightness). The current on a 0-10V control is generally around 1mA, so it represents nearly zero energy loss, but it results in some sensitivity to hum interference from parallel power lines (which can cause flickering) if the control cable is not shielded or run through grounded conduit. Another way to avoid interference or line losses is by placing AC-powered control modules very near the driver, which should be very near the fixture. Synapse Wireless, for example, uses wireless RF (radio) links to its controllers, simplifying the challenges of adding centralized control systems to wiring for LED lighting.
It's not brand new & it's more for machines than for people but the utility of MQTT (not it's official name, but you may want to think of it as the Message Queueing Tight Transport) makes it worthy of attention in the IoT machine-to-machine era. It's a many-to-one & one-to-many way to transfer information over an IP connection without a lot of protocol overhead & with very minimal programming. Any endpoint can be in any to all 3 of its roles: pub (publisher, meaning message originator), sub (subscriber, or message recipient) or broker (a metaphorical post office for collecting & distributing messages). Pubs & subs relate to topics, which can have hierarchies (much like folders under Windows); for example, each & every drive in a server room can separately send its current temperature reading through individual topics to any number of end points subscribed to those topics & topic subscriptions may include wildcards. MQTT is especially useful when sensors, controllers & actuators are widely distributed or where multiple transports can only funnel their collections of communications through a single IP hub or gateway or funnel.
Surveys showed us years ago that one in every six houses spends $50 or more each year on weather-related purchases, from thermometers to apps to amateur weather stations; beyond curiosity & beyond knowing how to dress for the day, what's the worth of weather awareness? In a smart house context, the driving reason outdoors for watching weather is in the gardens & lawns & the tangible value of having to repair or replace them if they come to harm. Watering cycles governed by past & forecast rainfall, temperatures, solar radiation levels, winds & humidity can help optimize (or at least not sacrifice) the health of plantings. Advanced home weather stations can provide much of this information in real time & irrigation specialists can determine the plant & soil types in each zone to identify target settings. API access to online weather micro-forecasts can fill in any blanks. A second reason is that the onset of abrupt outdoor temperature changes, beyond temporarily impacting indoor comfort, can stress HVAC heating or cooling systems in ways that can accelerate their need for maintenance, repair or replacement. The well-documented direct impact of weather is familiar, but the-chain-of-consequence costs & impact are seldom considered.
Faraday's original discovery of the relationships between magnetism, motion & electricity has always been most commonly exercised in rotating motors or generators; generally, 2 of these 3 phenomena produce the third, but their role isn't always obvious. If you start with magnetism coming from the Earth's field & add a coil but don't add motion, nothing happens, which is a starting point for some clever sensor technology. Rather than moving the magnetic field, disrupt it & that change also produces electricity. That's the most common trigger for a motorized gate opening to let you out: a buried coil beneath or beside the driveway has its exposure to the Earth's magnetic field disrupted by the ferric mass of your car & the short Voltage blip that results is enough for a control system to read. If you add a second coil, you can also determine (or at least infer) direction. Such sensors are immune to lightweight or magnetism-irrelevant objects & so are unlikely to sense people or animals crossing. Also, where active magnetic security systems may be easily detected with as simple an instrument as a compass, remote detection of these sensors is extremely difficult.
If you were to take any room in your home or office & divide it into 64 separate sectors, the spread in temperatures among those sectors may be indicative of simple to serious scenarios. Rooms tend to have only 1 or 2 heating or cooling ventilation sources & probably windows so some spread of temperatures may be expected. If that spread is more than minimal, a ceiling fan to stir the air may be the only remedy needed but if that's insufficient, identification of the true causes may help avoid more dramatic costs than the energy waste if early signs can help address other problems before they become major. When uneven heating or cooling results from poor or degrading insulation, it is unlikely to be isolated to a single room & it can cause enough extra wear & tear on comfort systems to accelerate their need for maintenance or replacement. The same is true if the cause turns out to be blocked or leaking ductwork. Short of a detailed grid of measurements, a few thermometers known to show the same temperature when in the same place can allow even casually interested people to determine if a more-involved thermal review may be worth pursuing.
Sloppy terminology usage by marketers is at the root of much of the public not understanding the differences between surveillance & security. Surveillance refers to observation or scrutiny (its French root means to watch). Surveillance isn't about protection, which is more the domain of security (its French & Latin roots mean free from care). Protection means separation from threats or dangers. Home automation camera or monitoring products, for example, that claim they provide security in fact do not; you may be able to witness harmful developments but there is nothing within them that offers any true protection. Locks can provide a measure of security but make no pretense of surveillance. When remote monitoring products make users aware of threats to security, the only choices are to surrender to the circumstance or to choose someone to send into harm's way. It is misleading to market surveillance as security, but until the public understands the difference, marketers are unmotivated to change. Further, there's a longstanding example of surveillance & security not being separate: Dogs do both.
Model aircraft used to be simply fly-by-wireless remote-controllable objects; increasingly, they are becoming better instrumented, self-reliant & intelligent, all of which are accelerating through the booming popularity of consumer & commercial drones. Even cars today that are not autonomous are nevertheless much better equipped for accident prevention, navigation, fuel economy, self-monitoring & communication extensibility. Household technology sees some of the same advancements but, because so many of the price points of relevant goods are much lower, there is also a good deal of masking beneficial improvements behind hype. No robot vacuum can yet dodge dog droppings. No residential security system can do anything to stop an in-progress incident. Very few home automation products can accomplish very much that's any more complicated than temperature or schedule settings without direct human assistance. There are indeed advancements (like variable speed heating/cooling systems or tankless hot water heaters or intelligent irrigation systems) but the irony is that because they can accomplish their tasks absent that requirement for human participation, even those people for whom their contributions are not invisible tend to take them for granted & ignore them.
Small digital signs (like the Visionect we earlier reviewed) use E-Ink displays, like that of the Kindle, to maintain an image while requiring close to no power; it draws slightly more power when its displayed image changes. It operates something like a browser, in that it is displaying one page only fed over an IP connection from a specialized server. The display is gray-scale monochrome. Popular applications for e-reader or tablet-size digital signs include conference room status, calendars, brief notices & other occasionally changing information displays. Smaller digital signs appear in applications like retail shelf pricing; larger ones tend to be adapted from color displays & may include animations or video. In the context of our project house, a 6” Visionect digital sign mounts at the front door, framed by a case with a Plexiglas front & LED lighting so the display can be front-lit at night. It normally serves as a vanity panel, showing either the house number or the family name. The option of reversing (from white-on-black to black-on-white) is there & we will determine that based on actual in situ readability tests. The reason for using a digital sign in this position is its ability, in case of a fire, to display a floor plan of the house indicating the position of every warm body (human or pet) & of every hot spot, helping fire response teams prioritize. That display is created on an internal server as an active HTML page that displays readings from 1,920 thixels (thermal pixels), sent to it from the 30 CAP (Ceiling Awareness Pod) sensor heads in the house, each sporting an 8x8 Panasonic Grid Eye thermal sensor updating 10 times per second. Because the digital sign can accept this active HTML, the server can also create a similar page accessible over the local intranet for deskside monitoring or for room-by-room monitoring with a tablet. An alternative approach could make a digital sign perform as an occasional “snapshot” reader for monitoring many kinds of data, including gray-scale images when motion triggers a surveillance camera.
Off-the-shelf technology exists that can measure temperatures everywhere in a residence in thixels (thermal pixels), each roughly 2 feet square at the floor when viewed from above, with 8x8 grids of these read at one time, up to 10 times per second. Simple analysis of these readings provides many kinds of interesting information. We earlier discussed how a threshold temperature setting can categorize which readings a system might interpret as a warm body & which a background temperature; warm body readings are key to identifying occupancy versus vacancy more precisely than with motion detection. Warm-body thixels near such entry/exit points as doors also provide an aid for lighting system control, helping anticipate occupant needs. Considering the thixel grid, a second temperature threshold can indicate dangerously uncomfortable heat levels in a room; higher still, another can indicate temperatures that are possible precursors to combustion (noting that thixels known to include cooktops or fireplaces can be programmatically ignored). Warm body active map displays that overlay a floor plan can help firefighter response decisions. Averaging the non-warm-body thixels offers a better room temperature reading than any single thermostat placement. If there is a sizable gap between the minimum & maximum thixel readings, a system can first try stirring the air with an available ceiling fan & if the gap endures, then notifying occupants. Lighting control operations, HVAC comfort system operations, energy costs, maintenance costs & occupant comfort all improve.
Compared to the winds of ventilation air movement, the air flow of a heat-recovery ventilator (HRV) or an energy-recovery ventilator (ERV) is just a soft breeze, but the differences between these 2 systems, their benefits & their trade-offs still cause confusion. Both are balanced ventilation systems & lower-energy (but higher initial cost) alternatives to exhaust-only (fans or blowers ported to the outside) or central-fan integrated-supply (which opens a damper to the outside for a while as an HVAC system runs) ventilation systems. Both types of balanced system (so-called because they simultaneously take in & exhaust air in like amounts) provide some thermal exchange (pre-conditioning incoming air to be more like the outgoing air) with little or no airstream intermixing. An ERV also supports enthalpy transfer, transferring moisture from the more humid air stream to the dryer airstream; in an air-conditioned house, this means lower total energy usage than using an HRV because of the lower additional dehumidification load. The air exchange helps remove stale or musty indoor odors, helps maintain a more natural balance between carbon dioxide & oxygen in indoor air & helps dilute indoor pollutants. Either kind of system can piggyback on existing ductwork (called a simplified system); or half-piggyback with dedicated ductwork pulling stale air out of bathrooms & pushing fresh air into the existing cold air return (called an exhaust-ducted system); or run its own dedicated ducts to pull from bathrooms & push into bedrooms & living spaces (called a fully ducted system). Because the first two installation approaches involve cooperative control of the main HVAC system fan, a fully ducted installation tends to be the most effective at the least energy cost.
As a category for retailer & installer products, home automation places no small emphasis on adding glitter & glamor to the lowly thermostat. The thermostat itself was one of the first home automation products to earn residential ubiquity, using physical changes (especially in bimetal springs) to control electrical switching (initially through the tilt of mercury switches) & thus control the on/off cycles of furnaces & later, air conditioning. This is still a central function of the so-called smart thermostats, but it's interesting to see what vendors do to gain attention & perhaps sales. In no particular order, these added features have included timer-based shifts, smart phone remote readings & control, weather displays on the thermostat face, digital picture frame displays, an ability to respond to one or more remoted temperature readings within the home & more. No thermostat we've seen can identify issues with the HVAC system, like refrigerant leaks or back-pressure or ventilation losses, despite such information already being available or easy & economical to add to most contemporary HVAC systems. Those that can show weather forecasts do not, as far as we've seen, control comfort system cycles to allow them to more slowly, gently & economically adapt to expected abrupt changes in outdoor air pressure or temperature. We have not yet seen a thermostat that will cut off comfort system fans & blowers when there's a fire in the house. For many, in their quest for attention, they pay scant attention to being more useful.
This comes out of things we are learning as we seek to use DC feeds in place of batteries across our editorial house project. The DC feeds derive from the high-current 3.3, 5 & 12 Volt supplies of a repurposed computer PSU (power supply unit). There are several such supplies, each plugged into a sinewave UPS & with a backup generator on site. Wiring itself can represent a significant resistance to low-voltage runs, which calls for countermeasures. One of those is the specification of 14-gauge wire; since current travels along the outer skin of a conductor, its larger diameter results in less path resistance. Another is the splitting of loads among the several PSU + UPS supply centers, reducing both the current demanded of any one line & the length of runs, ergo the run resistance. A third is the inclusion of capacitors at the far end of the run; a capacitor maintains the highest charge (Voltage) placed on it, discharging (like a battery) into loads when its Voltage is higher than the supply line Voltage. The scale of capacitance we employ (1000 μF) require the use if electrolytic capacitors, which have several known failure modes, most commonly involving higher Voltage or higher temperature compromising its rolled-layer construction. We counter this by specifying capacitors designed for a higher Voltage (50 VDC in usage where it should always see 12 VDC or less) & tolerant of higher temperatures (105°C, about 220°F, more than its surroundings will reach). Prudent design presumes all attached equipment running at its maximum draw; real life seldom sees that circumstance; so on rare occasions when the net draw of a supply line is temporarily high enough to threaten to make its Voltage dip, the capacitors provide a buffer against that. Line taps (“side street” feeds off a main run) are also a concern because some splice or tap products slice into wiring, effectively yielding a smaller diameter ergo greater resistance; some also invite oxidation over the long term, so tap or splice connection alternatives require testing & review.
When is it right to water the lawn (or other plantings)? Assuming there's no water embargo in place, watering based on a schedule is, at best, a coarse approach. Watering based on urgent needs seems a perilous practice. Part of understanding when to water is understanding when you don't need to water & intelligence in any smart watering system must pay attention to both; in fact, smart watering requires instrumentation, a local database & remote API access to any relevant weather events that are en route should all be part of what programming considers. If the soil moisture reads as good, there's nothing to do. As soil moisture levels drop, long before any danger point, the program can analyze the rate of fall, what weather factors are forecast (rain, high heat, high or low humidity, high winds) then, based on those, determine when to check again; note that this is still a “don't need to water” status. A further drop in soil moisture gets the programming to analyze the forecast information against time of day to determine the best time to water. Wind, heat, calculated evaporation rates, landscaper recommendations & a stored fudge factor fold into the recipe to determine the duration of watering; A few hours after watering, soil moisture readings determine whether the duration might need tweaking & make adjustments to the stored fudge factor. This approach creates an adaptive system that tunes itself to the actual needs of the actual (not just theoretical) on-site soils. That attention is merited to a small degree by conservation of water & to a much greater degree by the very high costs of remediating or replacing failed plantings as a result of over- or under-watering.
Is the floor, the wall or the ceiling the best place for air duct ventilation registers? Specific to the warmer Southern climate (more cooling days than heating days) of our project house, a study of convection led us to conclude that ceiling mounting is best for both vent & return registers. (There is also a practical factor: Flows are uninterrupted by furnishings or clutter). In warm weather, cooled air naturally drops toward the floor while warmer air naturally rises, together contributing to an overall steering of air in the room & allowing the net air mass to reach its desired temperature more quickly. When the space needs heating (rather than cooling), the incoming warmed air won't naturally fall to the floor, but will get pushed there by the HVAC system blower. That would be somewhat less efficient than a convective flow in an empty space with heat outlets & return registers both below, but within the context of modifying free air temperature, the density of furnishings & clutter at lower levels introduces other inefficiencies that more than balance out the difference. In short, the free air path near ceiling levels becomes the greatest influence in locating registers & returns. This presumes, of course, that spaces above & below - as well as the ductwork – are all well-insulated.
Exterior residential doors commonly combine a doorknob, not always lockable, with a deadbolt. Electronically controlled residential deadbolts in the home automation category are motorized retrofits, usually with battery packs & radio modules on the interior side; curiously, part of their appeal is an ability to unlock the door for others when you're not home. Some locks for more advanced residential systems derive from commercial products & incorporate such features as keypads, made less secure over time as it becomes easier to determine which few keys are frequently pressed. The solution we found for our project house may be applicable elsewhere, so we'll detail it here. Our requirements are simple: a key must always be able to lock or unlock the door, but electronics should also be able to do so. (We will soon review the specific products involved, but for the purposes of this report, a categorical description is more appropriate). The trade refers to these not as electronic locks but as electrified locks; the lock holds when 24-Volt (AC or DC) power is present. Its power feeds invisibly through conductive hinges. It is considered “fail-safe” in that if power should fail, the door is unlocked. On the exterior side, its standard lock cylinder has 6 pins, making it a little more difficult to pick or bump; on the interior side there's a plain knob allowing immediate egress at all times. The latch is a dead-latch (stiffener bar) design, not a spring latch, so nobody can get in with just a credit card or bent coat hanger. A key will always work so it avoids the battery issues of electronic locks. Absent WiFi or Bluetooth, hackers get no direct access. Automation can open these doors for first responder access or lock them if there's a suspected intruder, or just because it's bedtime.
The biggest demand for water capacity & pressure in most residences so equipped is for the fire sprinkler system, with a requirement to provide a flow rate of 16 gallons per minute through 2 heads simultaneously (so 32 GPM total) for at least 10 minutes (so 320 gallons). Where the source of that water is a deep well, this sets a high required flow rate for the well pump, meaning a higher-horsepower pump; the prescription for a 400-foot-deep well is a 5 HP pump that pulls almost 5 KW of power when running. Given that fires hardly ever happen & that the sum total of all other residential water usage happening at once is far lower than that flow requirement, an energy balance emerges by addressing what goes between the pump & the house, metaphorically a battery (or capacitor). In this example, a 100-gallon bladder-pressurized tank (most well pressure tanks are much smaller) can keep a pressurized source of water available that can handle the needs of the house for as long as days at a time, engaging the pump again only as it begins approaching empty. This means only infrequently operating the pump, conserving both energy & mechanical longevity. If we want out cold water to stay colder than room temperature, it does require a blanket of closed-cell insulating foam on the tank, which involves no ongoing cost after installation. Note that in our editorial project house, the well depth is less than 100 feet & a variable-frequency 2 HP submersible from DAB Pumps can easily support a 39 GPM flow at that well head depth; this means the pressure tank can be much smaller, the pump will not often be asked to deliver anything close to its full capacity & as a result, its in-service longevity without requiring major repairs or replacement should go well beyond the 40-year target of the project.
Advanced 911 systems that can respond to text messages or direct IP communications are being deployed in some limited areas, but nationwide, voice phone calls are still the only way to reach most 911 systems to report an emergency. As we prepare a house capable of autonomously placing emergency phone calls, we've been in touch with people serving at various levels of 911 call center management. The essence of the content that they would like automation to communicate is what you might anticipate they hope to hear in live calls: the nature of the emergency, the location, any special circumstances that might impact how to respond & so on. New call center personnel might not be aware of the ability of automation to place such calls, which makes the preamble of the call important. Opening with “This is an automated call,” for example, might result in an immediate disconnection; it's smarter to open with “This is an emergency call from an automated system at the following address.” Automation may also be able to provide additional helpful information, like whether or not anyone is home, whether the peril is outdoors or indoors, whether the threat is to property or to life & whether the first responders will find the exterior doors locked or unlocked. Relatively low pay & high stress (caller panic is commonplace) lead to an ongoing churn in at least some of the work force in most 911 centers, so clarity in the message content is important, especially when there is not a human caller available to answer questions.
Some recent improvements in non-electronic approaches to homebuilding seem to be based on metaphors you can encounter in electronic components & systems. Not long ago, many home support devices had only two states, on or off, making them by definition binary devices; some improvements came by taking approaches used in analog devices. The feedback loop, for example, is a way in which electronic devices can adapt their performance to the real-time demands of their load. Variable-frequency-control well pumps, modulated HVAC elements & scroll compressors achieve energy reductions, performance improvements & improved longevity by following similar load-responsive design principles. The pressure tank found on well systems acts as a capacitor in two ways: it both stores energy by compressing air in an inner bladder & stores water; as a result, such a tank can provide a home's water needs for a while without triggering pump operation. Similarly, the Ecovent Systems controller algorithms greatly reduce the number of times a connected thermostat turns an HVAC system on or off. When electronic designs can reduce idle current (the energy draw of an inactive standby mode) it's as much a stop-loss tactic as the improvement of a heating or cooling system's insulation. Right-sizing ductwork & running it without leaks or bends is very much like matching a transmitter to a cable & an antenna (for those who understand radio, it's also like reducing the standing wave ratio).
Heat pumps remain somewhat effective even at low temperatures; one expert reports his home's system can still carry 75% of the heating load even when outdoor temperatures drop into the mid-20s. The most common method of filling in the heating gap is to add supplemental electric heater strips that kick in at low temperatures; in areas with higher electrical rates or requiring many hours of supplemental heat, these can result in jarring boosts to the electric bill. At a slightly higher initial cost, many systems add a gas furnace, setting it to kick in at those cold temperatures where the heat pump can't quite be enough to maintain comfort levels. (One down side of gas furnaces is that they tend to be specified too robustly, especially where local codes are not updated to consider their use in conjunction with a heat pump; the result may turn out to be an uncomfortable house with uneven heating & overkill-induced hot spots). A more recent approach uses hydronic forced air heat, in which a hydronic coil in the air handler draws hot water from the home's tankless hot water heater to warm the comfort system's air flow. When a home is built tightly (no air sneaking through gaps in walls, windows, or doors) with attention to insulation, hydronic heat advantages over a furnace include a lower initial cost, lower energy costs & more level comfort levels. Choices among these three alternatives hinge on initial costs, comparative energy costs, the climate (especially the typical number of days per year with temperatures below freezing), the specifics of the heat pump & whether or not a tankless hot water heater is already present.
The Raspberry Pi Model 3 B, though only about the size of a deck of cards, sports some significant specs: 1.2GHz 64-bit quad-core CPU, 1GB RAM, 3D graphics core with full HDMI port, 100Mbps Ethernet, 802.11n WiFi, Bluetooth 4.1/BLE & more. It's in wide use in education, among hobbyists & in prototyping operations but there are things about it that make it difficult to deploy for more serious work, some of which are now being solved by a small firm, Picocluster. When an application calls for the involvement of more than one such RPi (jargon for Raspberry Pi), there's a mechanical challenge of securing them to a rack shelf in an orderly & accessible arrangement; the Picocluster solution centers around corner-post spacers & small L feet. Where communications among them is ordinarily difficult, they offer a very lightly modified version of the standard Raspbian (O/S) distribution that more readily supports fixed IP addressing. Picocluster began in business to support desktop cluster computing using small controllers like the RPi but true cluster computing is not mandatory; simple cooperative computing or peer/near-peer network attachment of even dozens of small computers fits as well.
We should stipulate that our context for this is our own automated home environment in which a control system governs whether external doors are locked or unlocked; nothing on the doorknob itself that can change that mode. A plain inside knob always allows exit; a key always allows entry; but entry without a key is only possible when the electrified lock is off. That makes it mechanically easy to lock yourself out of the house & if that happens when you don't have a key, there's no easy recourse. The conundrum for automation centers on how to keep access available at the convenience of those who should be allowed entry without making the home vulnerable to those who should not. Warm body tracking, for example, can help recognize when somebody exits the house into the garage & conditionally maintain an unlocked status as long as a garage door isn't open; if there is any confusion about a continuing presence, automation could offer a 1- or 2-minute warning before again securing the lock. Accepting that automation can't anticipate every circumstance in which a righteous occupant might be denied entry, there seems to be some need to create a figurative back door, meaning an unlocking mechanism that does not require a key but is nonetheless not creating a security vulnerability. Hiding a key externally is unwise, but patterns of activities that seem unrelated to access may provide a way for allowing a house to be more permissive for those authorized occupants or guests who don't yet appreciate just how foolish it can be to go out the door while leaving that key behind.
While investigating our wish list for internal networks & external internet access (in the context of our http://40yearhouse.com project) we identified a role or hardware firewalls that is uncommon in any but enterprise installations. Adding a second source for WAN access adds redundancy in the event of an outage or failure; while we expected that to take the form of main & fallback connections, contemporary products are more likely to aggregate multiple connections, meaning the greater value of greater throughput when both are active with zero latency if either should fail. In our case, at least initially, that's a wider-band connection through our cable modem & a secondary path through an AT&T U verse fiber connection. Of the 4 quite separate LAN connections, one will work as ours now works, connecting our wired ports & a WiFi access point… a second LAN will connect to a second “guest” access point, absent easy peer connections to our first LAN’s gear… a third & fourth will have no WAN access (except for the NTP time port), with one of these intranets for our PoE surveillance cameras & the other for our automation control system.
Few people know what a contactor is despite having been around them all their lives; the term relay is a little more familiar & a contactor is essentially a relay made to handle more current (ergo more power). An electromechanical relay (as well as a contactor) works by having an electromagnet pull sets of contact points together or apart, so the small amount of power that the electromagnetic coil uses can create on-off control over higher-power equipment. Contactors are often used to engage compressors in refrigerators, freezers or air conditioning compressors, for example, as well as water pumps & large motors. Within the contactor, the making & breaking of connections at the contact points is generally accompanied by electrical arcing, which produces heat & also tends to both create some contact point pitting & some depositing of carbon on them. Those factors dramatically reduce the reliable operating life of contactors and thereby create maintenance or replacement needs for the systems in which they're embedded & may be a factor in motor burn-out. Recent technology improvements in arc suppression (at typically around $30 per contactor) offer some promise of eliminating many such costs & problems.
Watering the residential lawn & plantings began with simply turning on sprinklers for a while to water a lawn then sooner or later turning them off & moving them; the first automation put a timer on the hose & the next round buried sprinkler heads in zones selectively controlled by a mechanical timer. Newer automation approaches tie in Web-fetched weather data to avoid the always curious phenomenon of lawns being watered during rain showers. Some systems added wind sensors to avoid spray-away; some add soil moisture sensors to their control decision matrix. The next generation of watering automation is likely to involve a classic feedback system in which watering doesn't happen in a single cycle. The start of a zone's watering would reflect historic, current & forecast weather conditions, a profile of the needs of the plantings & current measured soil conditions; the initial watering would be deliberately short of the water-need goal. As all zones go through similar first cycles, new soil condition readings will determine whether a “booster” watering is appropriate. A single watering episode may involve several such cycles, but this approach helps assure that the plantings are neither over- nor under-watered. Even in water-restricted areas, while this approach does offer some benefit in its husbandry of water usage, the primary benefit is in avoiding the expensive repair or replacement of lawns & plantings.
In today's home automation product categories, most systems involve the installation of multiple products & their configuration, with seldom less than 3-figure price tags & some into 4 figures & beyond. Users of those systems seldom consider that products with 2-figure price tags can provide similar results. Motion-detecting lights in wall sockets & elsewhere meet some such needs; plug-in timers meet some; enhanced remote controls meet some. Electronic deadbolts that require a Bluetooth dongle or handset app to open are less convenient than using a key; if they allow remote unlocking, they also compromise the safety & security of the home. Indoor cameras may compromise privacy & permit identity theft. People with evil intentions already recognize talking doorbells as a sign that nobody is really home. Technology trends are seductive to many & driven more by emotion than by reason; accomplishing simple conveniences mostly to show off that your home is now a “fun” peripheral for a smart phone carries with it too many threats & vulnerabilities to be thought of as anything other than unwise.
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