Homekit Compatible Sonoff Firmware Without A Bridge

Generally speaking, home automation isn’t as cheap or as easy as most people would like. There are too many incompatible protocols, and more often than not, getting everything talking requires you to begrudgingly sign up for some “cloud” service that you didn’t ask for. If you’re an Apple aficionado, there can be even more hoops to jump through; getting your unsupported smart home devices working with that Cupertino designed ecosystem often involves running your own HomeKit bridge.

To try and simplify things, [Michele Gruppioni] has developed a firmware for the ubiquitous Sonoff WIFI Smart Switch that allows it to speak native HomeKit. No more using a Raspberry Pi to act as a mediator between your fancy Apple hardware and that stack of $4 Sonoff’s from AliExpress, they can now talk to each other directly. In the video after the break you can see that the iPad identifies the switch as unofficial device, but since it’s compliant with the HomeKit API, that doesn’t prevent them from talking to each other.

Not only will this MIT licensed firmware get your Sonoff Basic, Sonoff Slampher, or Sonoff S26 talking with your Apple gadgets, but it also provides a web interface and REST API so it retains compatibility with whatever else you might be running in your home automation setup. So while the more pedestrian users of your system might be turning the porch light on with their iPhones, you can still fire it up with a Bash script as nature intended.

Of course, if you don’t mind adding a Raspberry Pi bridge to the growing collection of devices on your network, we’ve got plenty of other HomeKit-enabled projects for you to take a look at.

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A Sonoff Switch Repurposed As A Thermostat

Underfloor heating is a wonderfully luxurious touch for a bedroom and en-suite bathroom, and [Andy] had it fitted so that he could experience the joy of walking on a toasty-warm floor in the morning. Unfortunately after about a year it stopped working and the culprit proved to be its thermostat. A replacement was eye-wateringly expensive, so he produced his own using an ESP8266-powered Sonoff wireless switch.

The thermostat has a thermistor as its temperature sensor, embedded in the floor itself. This could be brought to the ESP’s solitary ADC pin, but not without a few challenges along the way. The Sonoff doesn’t expose the pin, so some very fine soldering was the first requirement. A simple voltage divider allowed the pin to be fed, but through it he made the unfortunate discovery that the ESP’s analogue input has a surprisingly low voltage range. A new divider tying it to ground solved the problem, and he was good to go.

Rather than using an off-the-shelf firmware he created his own, and with a bit of board hacking he was able to hard wire the mains cabling and use one set of Sonoff terminals as a sensor connector. The whole fit neatly inside an electrical fitting box, so he’s back once more to toasty-warm feet.

This isn’t the first ESP thermostat we’ve featured, nor will it be the last. Here’s a particularly nice build from 2017.

Old Wireless Switches Join The Internet Of Things

Just about any appliance comes in an internet enabled version nowadays. However, even the oldest gear can be switched on and off with an Internet connected power socket. [Bill] is in the process of automating his home, and found some old radio controlled power sockets that badly needed to join the 21st Century. Hacking ensued.

The first set of switches [Bill] came across were easy to work with. Eager to keep things as functional as possible, ESP8266s with Tasmota firmware were wedged into the enclosures. With a bit of circuit sleuthing, [Bill] was able to set up the switches to respond to commands from both the ESP8266 as well as the original push buttons and radio remote.

[Bill] later came across some black switches, which were not up to his standards. These switches were gutted entirely, being used only for their mains plug and enclosure. The relays inside were replaced with 5V versions which were easier to trigger from the ESP8266’s outputs.

[Bill[ readily admits that the cost benefits over buying off-the-shelf Sonoff modules don’t really add up, but good hackers rarely let such concerns get in the way of a fun project. Around these parts, we see plenty of hacks to automate your house – like this zero-intrusion light switch mod. Happy hacking!

The Heat Is On With This ESP8266 Controlled Sauna

We’ll be perfectly honest: sitting inside a heated box sounds just a bit too much like torture for our tastes. But if we did somehow find ourselves in possession of a fancy new sauna, we’d more than likely follow in the footsteps of [Al Betschart] and make the thing controllable with the ESP8266. After all, if you’re going to be cooked alive, you might as well do it on your own terms.

The sauna itself was purchased as a kit, and included an electric heater controlled by a thermostat. As explained in his detailed documentation, [Al] integrated a Sonoff TH16 into the original heater circuit so he could control power to the coils remotely. The TH16 also includes support for a thermal sensor, which allowed him to get a reading on the sauna’s internal temperature. The new electronics were mounted in a weather-proof box on the back of the sauna, complete with an external WiFi antenna to help get a good signal back to the house.

At this point the project could technically be done if all you wanted was remote control, but [Al] wanted to create a replacement firmware for the Sonoff that was specifically geared towards the sauna. So he came up with some code that uses MQTT to connect the heater to his home automation system, and allows configuring things like the maximum temperature and how long the sauna will run before turning itself off.

Interestingly, the company who makes these saunas thought the work [Al] did to integrate their product into his home automation system was so impressive they actually interviewed him about it and put it up on their site for others who might be inspired by his work. We’ve covered a lot of hacks to consumer devices here at Hackaday, and it’s exceedingly rare for a company to be so supportive of customers fiddling around with their products (especially in a case like this where there’s a real chance of burning your house down), so credit where credit is due.

The last time we brought you a sauna hack it was quite literally in a van down by the river, so the addition of an ESP8266 certainly brings this more into our comfort zone. Figuratively, if not literally.

[Thanks to Jon for the tip.]

Add Nest Functionality To Your Thermostat For $5

The Nest Thermostat revolutionized the way that people control the climate in their homes. It has features more features than even the best programmable thermostats. But, all of the premium features also come at a premium price. On the other hand, for only $5, a little coding, and the realization that thermostats are glorified switches, you can easily have your own thermostat that can do everything a Nest can do.

[Mat’s] solution uses a Sonoff WiFi switch that he ties directly into the thermostat’s control wiring. That’s really the easy part, since most thermostats have a ground or common wire, a signal wire, and a power wire. The real interesting work for this build is in setting up the WiFi interface and doing the backend programming. [Mat’s] thermostat is controlled by software written in Node-RED. It can even interface with Alexa. Thanks to the open source software, it’s easy to add any features you might want.

[Mat] goes through a lot of detail on the project site on how his implementation works, as far as interfacing all of the devices and the timing and some of the coding problems he solved. If you’ve been thinking about a Nest but are turned off by the price, this is a great way to get something similar — provided you’re willing to put in a little extra work. This might also be the perfect point to fall down the home automation rabbit hole, so be careful!

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A Tinfoil-Free Internet Of Ceiling Fans

Putting everything on the Internet is getting easier and easier, what with the profusion of Internet-ready appliances as well as cheap and plentiful IoT modules to integrate legacy devices. Think IoT light bulbs, refrigerators and dishwashers that can be controlled from a smartphone, and the ubiquitous Sonoff modules. But once these things are on the net, what are they talking about? Are they saying things behind your back? Are they shipping data about your fridge contents off to some foreign land, to be monetized against your will?

Maybe, maybe not, but short of a tinfoil helmet the only way to protect yourself is to build your own system. This IoT control for ceiling fans is a good example, with the added benefit that most wireless ceiling fan remotes are kind of lousy. [microentropie] didn’t like the idea of going the Sonoff route, so his custom controller is based on that IoT workhorse, the ESP8266. There are two versions, one switching the light and fan loads with relays, and one with triacs. The ESP serves up its own web page for control rather than using a cloud service, and is capable of setting up the fan to turn on and off automatically at preset times or temperatures. Everything sits in an unobtrusive box on the ceiling near the fan, but we bet this could be miniaturized enough to fit right inside the fan housing.

If some of [microentropie]’s code looks familiar, it might be because he borrowed it from his IoT rice cooker project.

Sonoff Postmortem Finds Bugs, Literally

While nobody is exactly sure on the exact etymology of the term, Thomas Edison mentioned some of his inventions being riddled with “bugs” in a letter he wrote all the way back to 1878. In the context of computers, any loyal Hackaday reader should know Grace Hopper’s infamous account of a moth being caught in an early electromechanical computer’s relays. To this pantheon of troublesome insects, we would humbly summit the story of a Sonoff TH16 switch being destroyed by a lowly ant.

According to [CNX Software], the Sonoff TH16 had been working perfectly for a year and a half before the first signs of trouble. One day the switch wouldn’t respond to commands, and a power cycle didn’t seem to clear the issue. Upon opening up the device to see what had gone amiss, it was clearly apparent something had burned up. But upon closer inspection, it wasn’t a fault with the design or even a shoddy component. It was the product of an overly curious ant who got a lot more than he bargained for.

Consulting the wiring diagram of the Sonoff, it appears this poor ant had the terrible misfortune of touching the pins of a through hole capacitor on the opposite side of the board. Bridging this connection not only gave him a lethal jolt, but apparently caused enough current to surge through a nearby resistor that it went up in smoke.

Now, some might wonder (reasonably so) about the conditions in which this switch was operating. If bugs could climb into it, it’s not unreasonable to assume it wasn’t well protected from the elements. Perhaps damp conditions were to blame for the failure, and the image of the ant “riding the lighting” is nothing more than a coincidence. Maybe. But sometimes you just gotta believe.

Incidentally, if you’d like to learn more about the woman who helped secure “bugs” in the IT lexicon, here’s a good place to start.

Ed Note: If you think you’re having deja vu all over again, we did point to this story in the Sunday Links roundup, but the graphics are just so good we couldn’t resist running it in full.