Most of North America has been locked in a record-setting heat wave for the last two weeks, and cheap window AC units are flying out of the local big-box stores. Not all of these discount units undergo rigorous QC before sailing across the Pacific, though, and a few wonky thermostats are sure to get through. But with a little sweat-equity you can fix it with this Arduino thermostat and temperature display.
We’ll stipulate that an Arduino may be overkill for this application and that microcontrollers don’t belong in every project. But if it’s what you’ve got on hand, and you’re sick of waking up in a pool of sweat, then it’s a perfectly acceptable solution. It looks like [Engineering Nonsense] got lucky and had a unit with a low-current power switch, allowing him to use a small relay to control the AC. The control algorithm is simple enough – accept a setpoint from an encoder, read the temperature sensor, and turn the AC on or off accordingly. Setpoint and current temperature are displayed on an OLED screen. One improvement we’d suggest is adding a three-minute delay between power cycles like the faceplate of the AC states.
This project bears some resemblance to this Arduino-controlled AC, but it seems more hackish to us. And that’s a good thing – hackers have to keep cool somehow.
Redditor [mulishadan] — a fan of the movie WarGames — has created a singular thermostat in the form of a Defcon alert meter.
Looking to learn some new skills while building, [mulishadan] tried their hand at MIG welding the 16g cold-rolled plate steel into the distinctive shape. A second attempt produced the desired result, adding a 1/4-inch foam core and painting the exterior. Individual LEDs were used at first for lighting, but were replaced with flexible LED strips which provided a more even glow behind the coloured acrylic. A Particle Photon board queries the Weather Underground API via Wi-Fi in five-minute intervals.
Each escalation in the Defcon alert signals an increase of 10 F, starting at Defcon 5 for 69 F and below, up to Defcon 1 for 100+ F. The final build looks like a true-to-life prop with some useful functionality that can be adapted to many different purposes — proof that a relatively simple project can still produce fantastic results for entry-level makers. So why not try making this thermostat scarf as well?
Although the Internet of Things (IoT) is a reasonably new term, the idea isn’t really all that new. Many engineers and hackers have created networked embedded systems for many years. So what’s different? Two things: the Internet is everywhere and the use of connected embedded systems in a consumer setting.
Like anything else, there’s a spectrum of usefulness to IoT. Watching The Expanse, the other day (which is not a bad show, by the way), I noticed that if you had the right IoT lights, you could run an app that would change your lighting to suit the show in real-time. I don’t have those lights, but I suppose when the action moves to a dark sub-basement, your lights dim and when you are in a space ship’s reactor room, they turn red, and so on. Fun, but hardly useful or life-changing.
On the other hand, there are some very practical IoT items like the Nest thermostat. It might seem lazy to want to monitor and control your thermostat from your tablet, but if you are frequently away from home, or you have multiple houses, it can be a real positive to be able to control things remotely. With the recent blizzard on the U.S. east coast, for example, it would be great to turn on the heat in your weekend cottage 150 miles away while you were still at work or home. However, the Nest recently had a hiccup during an upgrade and it has made many of their customers mad (and cold). I’ll get back to that, in a minute. First, I want to talk about the problems with deploying something that will be in many varied environments (like people’s homes) that controls something real.
[Sven337] was gifted a steam cleaner, and seemed pretty happy because it helped clean the floor better than a regular mop. Until it fell one day, and promptly stopped working. It would produce steam for a short while and then start spitting out cold water, flooding the floor.
Like any self-respecting hacker, he rolled up his sleeves and set about trying to fix it. The most-likely suspect looked like the thermostat — it would switch off and then wouldn’t switch on again until the water temperature fell way below the target, letting out liquid water instead of steam after the first switching cycle. A replacement thermostat was ordered out via eBay.
Meanwhile, he decided to try out his hypothesis by shorting out the thermostat contacts. That’s when things went south. The heater worked, and got over-heated due to the missing thermostat. The over-temperature fuse in the heater coil blew, so [Sven337] avoided burning down his house. But now, he had to replace the fuse as well as the thermostat.
[Sven337] bundled up all the parts and put them in cold storage. The thermostat arrived after almost 2 months. When it was time to put it all together, a piece of fibreglass tubing that slides over the heater coil was missing. Without the protective sleeve, the heater coil was shorting out with the grounded heater body, blowing out the fuses in his apartment.
That’s when [Sven337] called it a day and threw out the darn steam mop — a few dollars down the drain, a few hours lost, but at least he learnt a few things. Murphy’s Law being what it is, he found the missing insulation sleeve right after he’d thrown it away.
If you’ve ever lived in a building with manually controlled central heating, you’ll probably understand [Martin]’s motivation for this hack. These heating systems often have old fashioned valves to control the radiator. No Nest support, no thermostat, just a knob you turn.
To solve this problem, [Martin] built a Wi-Fi enabled thermostat. This impressive build brings together a custom PCB based on the ESP8266 Wi-Fi microcontroller and a mobile-friendly web UI based on the Open Thermostat Scheduler. The project’s web server is fully self-contained on the ESP8266.
To replace that manual value, [Martin] used a thermoelectric actuator from a Swiss company called HERZ. This is driven by a relay, which is controlled by the ESP8266 microcontroller. Based on the schedule and the measured temperature, the actuator lets fluid flow through the radiator and heat the room.
As a bonus, the device supports NTP for getting the time, MQTT for publishing real-time data, and ThingSpeak for logging and graphing historic data. The source code and design files are available under a Creative Commons license.
When [William’s] thermostat died, he wanted an upgrade. He found a few off-the-shelf Internet enabled thermostats, but they were all very expensive. He knew he could build his own for a fraction of the cost.
The primary unit synchronizes it’s time using NTP. This automatically keeps things up to date and in sync with daylight savings time. There is also a backup real-time clock chip in case the Internet connection is lost. The unit can be controlled via the physical control panel, or via a web interface. The system includes a nifty “vacation mode” that will set the temperature to a cool 60 degrees Fahrenheit while you are away. It will then automatically adjust the temperature to something more comfortable before you return home.
[William’s] home is split into three heat zones. Each zone has its own control panel including an LCD display and simple controls. The zones can be individually configured from either their own control panel or from the central panel. The panels include a DHT22 temperature and humidity sensor, an LCD display, a keypad, and support electronics. This project was clearly well thought out, and includes a host of other small features to make it easy to use.
Ever since [The Nooganeer] bought his first home with his wife back in the spring of 2014, he’s had ever consuming dream of adding home automation to every appliance. As he puts it…
Home automation has always been a fascination of mine. How much time and irritation would I save if I didn’t have to worry about turning things on and off, or wonder in which state they were left? How much more efficient would my home be? Wouldn’t it be cool to always know the state of every power consumer in my home, and then be able to record and analyze that data as well?
His first challenge was making a smart thermostat — after all, heating and cooling your house typically takes the most energy. Having used a Raspberry Pi before he figured it would be the best brain for his system. After researching a bit about HVAC wiring, [The Nooganeer] settled on a Makeatronics Solid State Relay board to control the HVAC. This allows him to use the GPIO’s on the Raspberry Pi in order to control the furnace and AC unit. Continue reading “Raspberry PiPhone Thermostat Monitors Your Entire House — Or At Least That’s The Plan”→