In an ideal smart home, the explosion of cheap WiFi and Bluetooth chips has allowed hundreds of small wireless devices to control the switches, lights, and everything else required for a “smart home” at a relatively low price. But what if you don’t want hundreds of internet-connected devices in your home polluting the wireless spectrum and allowing potential security holes into your network? If you’re like [Lucas Teske], you might reach for something wired and use cheap and (currently) available Raspberry Pi Picos to create PicoHome.
The unique twist of PicoHome is that it uses a CAN bus for communication. One of [Lucas’] goals was to make the boards easily swappable when hardware failed. This meant board-to-board communication and protocols like I2C were susceptible to noise (every time a relay triggered, the bus would lock up briefly). The CAN bus is designed to work in an electrically noisy environment.
There are two parts to the system: pico-relay and pico-input. The first connects to a 16 relay board and can control 16 different 24v relays. The second has 16 optoisolators to read from 12v-24v switches and various buttons throughout the house. These can be placed in a giant metal box in a central wiring location and not worry about it.
The firmware and board files are all released under an Apache 2.0 license, but the CAN2040 library this project relies on is under GPL. We covered the CAN2040 library when it was first released, and it’s lovely to see it being used for something entirely unexpected.
I ran into a guy at Maker Faire Kansas City who I used to scoop ice cream with twenty years ago. We were slinging frozen dairy at a Baskin Robbins in a dying suburban strip mall that had a one-hour photo booth in the parking lot. It was just far enough away from our doorstep that dotting its backside with the hard-frozen ice cream balls that had been scooped and then not always accidentally dropped into the depths of the freezer was challenging. This guy, [Blake], kept a hockey stick hidden in the back room especially for this purpose. I never could get them to fly that far, but he was pretty good at it.
