Parts List

You will need at least the below items (besides some Radbots to connect to!) for the project:

• Raspberry Pi with 40-pin header. The precise version isn't important, but you need a relatively modern one with 40-pin header to connect to the radio board below. I used a Raspberry Pi Zero WH (i.e. with inbuilt WiFi and pre-soldered header) from The Pi Hut.
• Adafruit RFM69HCW Transceiver Radio "Bonnet" for 868MHz, also advertised as for 900 or 915 MHz is probably fine - don't get the 433 ones for American radio bands. This is the key add-on that allows receiving the TRV messages, and avoids some tricky soldering using a naked RFM23 module, if the RFM69 took a little more work to configure. I got mine from Pimoroni!
• USB to TTL Serial Cable. Needed for reprogramming Radbot TRVs to a known key so you can decrypt their messages, e.g. The Pi Hut.
• Raspberry Pi power supply (USB Micro B cable). You probably have a few of these already from old Android phones, but you might need a more powerful tablet charger for older/more power hungry RPis. If you get mystery reboots or it doesn't even start to work, suspect a too-weak power supply.
• Blank MicroSD card, at least 8GB in size.

Non-critical but very useful parts:

• 868MHz aerial with uFL connector. According to the Adafruit docs you can solder on an 8.2 cm wire instead, as I did until I got a proper aerial from RF Solutions. (This improved signal strength a bit, but not that much - and watch that fragile connector!)
• Jumper wires. I found it easy to make a reprogramming tool to connect to the tricky Radbot serial pads using breadboard jumper wires from The Pi Hut.
• Raspberry Pi case - Useful to avoid damaging the RPi or radio board, but make sure you can fit the board in or access the header via a cut-out.