Hack My House: Raspberry Pi as Infrastructure

I finally had my own house. It was a repossession, and I bought it for a song. What was supposed to be a quick remodel quickly turned into the removal of most of the drywall in the house. There was a silver lining on this cloud of drywall dust and loose insulation. Rather than constantly retro-fitting cabling and gadgets in as needed, I could install everything ahead of time. A blank canvas, when the size of a house, can overwhelm a hacker. I’ve spent hours thinking through the infrastructure of my house, and many times I’ve wished for a guide written from a hacker’s perspective. This is that guide, or at least the start of it.

What do you want your smart house to do? And what do you want to be able to do in your smart house? For example, I wanted to be able to upgrade my cheap 120 V welder to a beefier 240 V model, so adding a 240 V plug in the garage was a must. As a bonus, that same 240 V circuit could be used for charging an electric car, if ever one is parked there.

“Ethernet everywhere” was my mantra. Try to imagine everywhere you might want to plug in a desktop, a laptop, an access point, or even a VoIP phone. I decided I wanted at least two Ethernet drops to each room, and tried to imagine the furniture layout in order to put them in convenient places.

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Raspberry Pi as 433 MHz to MQTT Gateway

Many low-cost wireless temperature and humidity sensors use a 433 MHz transmitter to send data back to their base stations. This is a great choice for the manufacturer of said devices because it’s simple and the radios are cheap, but it does limit what we as the consumer can do with it a bit. Generally speaking, you won’t be reading data from these sensors on your computer unless you’ve got an SDR device and some experience with GNU Radio and reading the Nexus protocol.

But [Aquaticus] has developed a very comprehensive piece of software that should make integrating these type of sensors into your home automation system much easier, as long as you’ve got a spare Raspberry Pi lying around. Called nexus433, it uses a cheap 433 MHz receiver connected to the Pi’s GPIO pins to receive data from environmental sensors using the popular Nexus communication protocol. A few known compatible sensors are listed in the project documentation, one of which can be had for as little as $5 USD shipped.

In addition to publishing the temperature, humidity, and battery level values from the sensors to MQTT, it even tracks connection quality for each individual sensor and when they go on and offline. To be sure, this is no simple hack. In nexus433, [Aquaticus] has created a mature Linux service with enough flexibility that you shouldn’t have any problems working it into your automation setup, whether it’s Home Assistant or something you’ve put together yourself.

We’ve seen a number of home automation hacks using these ubiquitous 433 MHz radios,  from controlling them with an ESP8266 to hacking a popular TP-LINK router into a low-cost home automation hub.

What’s Behind the Door? An IoT Light Switch

We’re not sure who designed [Max Glenister]’s place, but they had some strange ideas about interior door positioning. The door to his office is right next to a corner, yet it opens into the room instead of toward the wall. Well, that issue’s been taken care of. But the architect and the electrician got the last laugh, because now the light switch is blocked by the open door.

Folks, this is the stuff that IoT is made for. [Max] here solved one problem, and another sprang up in its place. What better reason for your maiden voyage into the cloud than a terrible inconvenience? He studied up on IoT servo-controlled light switching, but found that most of the precedent deals with protruding American switches rather than the rockers that light up the UK. [Max] got what he needed, though. Now he controls the light with a simple software slider on his phone. It uses the Blynk platform to send servo rotation commands to a NodeMCU, which moves the servo horn enough to work the switch. It’s simple, non-intrusive, and it doesn’t involve messing with mains electricity.

His plan was to design a new light switch cover with mounting brackets for the board and servo that screws into the existing holes. That worked out pretty well, but the weight of the beefy servo forced [Max] to use a bit of Gorilla tape for support. He’s currently dreaming up ways to make the next version easily detachable.

Got those protruding American switches? [Suyash] shed light on that problem a while back.

ESP8266 Internet Controlled LED Dimmer

There’s no shortage of debate about the “Internet of Things”, largely centered on security and questions about how much anyone really needs to be able to turn on their porch light from the other side of the planet. But while many of us are still wrestling with the realistic application of IoT gadgets, there’s undoubtedly those among us who have found ways to put this technology to work for them.

One such IoT devotee is [Sasa Karanovic], who writes in to tell us about his very impressive custom IoT LED dimmer based on the ESP8266. Rather than rely on a commercial lighting controller, he’s designed his own hardware and software to meet his specific needs. With the LED strips now controllable by any device on his network, he’s started working on Python scripts which can detect what he’s doing on his computer and react accordingly. For example, if he’s watching a movie the lights will automatically dim, and come back up when he’s done.

[Sasa] has provided all the files necessary to follow in his footsteps, from the Gerber files for his PCB to the Arduino code he’s running on the ESP. The source code is especially worth checking out, as he’s worked in a lot of niceties that we don’t always see with DIY projects. From making sure the ESP8266 gets a resolvable DNS hostname on the network to using websockets which update all connected clients with status info in real-time, he’s really put a lot of work into making the experience as complete as possible.

He’s explains in his blog post what needs to be edited to put this code to work in your own environment, and there’s even some descriptive comments in the code and a helpful debug mode so you can see how everything works. It’s always a good idea to consider that somebody else down the road might be using your code; taking a few minutes to make things clear can save them hours of stumbling around in the dark.

If you need more inspiration for your ESP8266 lighting project, check out this ambient lighting controller for a kid’s room, or this professional under-cabinet lighting controller.

Evolution of the ESP8266 Party Button

Sometimes the best part of building something is getting to rebuild it again a little farther down the line. Don’t tell anyone, but sometimes when we start a project we don’t even know where the end is going to be. It’s a starting point, not an end destination. Who wants to do something once when you could do it twice? Maybe even three times for good measure?

Original version of the Party Button

That’s what happened when [Ryan] decided to build a wireless “party button” for his kids. Tied into his Home Assistant automation system, a smack of the button plays music throughout the house and starts changing the colors on his Philips Hue lights. His initial version worked well enough, but in the video after the break, he walks through the evolution of this one-off gadget into a general purpose IoT interface he can use for other projects.

The general idea is pretty simple, the big physical button on the top of the device resets the internal ESP8266, which is programmed to connect to his home WiFi and send a signal to his MQTT server. In the earlier versions of the button there was quite a bit of support electronics to handle converting the momentary action of the button to a “hard” power control for the ESP8266. But as the design progressed, [Ryan] realized he could put the ESP8266 to deep sleep after it sends the signal, and just use the switch to trigger a reset on the chip.

Additional improvements in the newer version of the button include switching from alkaline AA batteries to a rechargeable lithium-ion pack, and even switching over to a bare ESP8266 rather than the NodeMCU development board he was using for the first iteration.

For another take on MQTT home automation with the ESP8266, check out this automatic garage door control system. If the idea of triggering a party at the push of a button has your imagination going, we’ve seen some elaborate versions of that idea as well.

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Hacking a Sonoff WiFi Switch

The ESP8266 platform has become so popular that it isn’t just being used in hobby and one-off projects anymore. Companies like Sonoff are basing entire home automation product lines around the inexpensive WiFi card. What this means for most of us is that there’s now an easily hackable and readily available product on the market that’s easily reprogrammed and used with tools that we’ve known about for years now, as [Dan] shows in his latest project.

[Dan] has an aquaponics setup in his home, and needs some automation to run the lights. Reaching for a Sonoff was an easy way to get this done, but the out-of-the-box device can only be programmed in the simplest of ways. To get more control over the unit, he wired a USB-to-Serial UART to the female headers on the board and got to programming it.

The upgraded devices are fully programmable and customizable now, and this would be a great hack for anyone looking to get more out of a Sonoff switch. A lot of the work is already done, like building a safe enclosure, wiring it, and getting it to look halfway decent. All that needs to be done is a little bit of programming. Of course, if you’d like to roll out your own home automation setup from scratch that can do everything from opening the garage door to alerting you when your dog barks, that’s doable too. You’ll just need a little more hardware.

ESP8266 Beacon Announces Your Arrival

It used to be people were happy enough to just have to push a button in their car and have the garage door open. But pushing a button means you have to use your hands, like it’s a baby toy or something. We’re living in the 21st century, surely there must be a better way! Well, if you’ve got a home automation system setup and a spare ESP8266 laying around, [aderusha] may have your solution with MQTTCarPresence.

The theory of operation here is very clever. The ESP8266 is powered via the in-dash USB port, which turns on and off with the engine. When the engine is started, the ESP8266 is powered up and immediately connects to the WiFi network and pushes an MQTT message to Home Assistant. When Home Assistant gets the notification that the ESP8266 has connected, it opens the garage door.

When [aderusha] drives out of the garage and away from the house, the ESP8266 loses connection to the network, and Home Assistant closes the door. The same principle works when he comes home: as the car approaches the house it connects to the network and the garage door opens, and when the engine is shut off in the garage, the door closes again.

The hardware side of the setup is really just a WeMos D1 mini Pro board, though he’s added an external antenna to make sure the signal gets picked up when the vehicle is rolling up. He’s also designed a very slick 3D printed case to keep it all together in a neat little package.

We’ve covered automated entry systems based on the ESP8266 before, though usually the ESP stays at home. Be sure to check out the awesome series [Elliot Williams] has on the wonders of MQTT if you’re looking to setup your own automation system.