Depending on your security needs, you can go back to transistors à la Ben Eater. Or an Arduino, or a permanently-offline device with its Wi-Fi card unplugged an

Depending on your security needs, you can go back to transistors à la Ben Eater. Or an Arduino, or a permanently-offline device with its Wi-Fi card unplugged and its Ethernet cable desoldered or poured-in with hot glue/plastic. Also desolder/unplug the speakers/microphone while you're at it; there may be some air gap leaks that way. Ideally, only use it on a separate power supply also (say, an older vehicle without networking capabilities, or a solar panel). Check out the Glacier protocol for inspiration: https://glacierprotocol.org/docs/overview/ https://glacierprotocol.org/docs/overview/