PJON - An open wired bus with up to 254 devices over single wire.

[ei23fxg]

Hi! I'm currently tinkering with PJON (pjon.org). There are multiple options for communication, "it's just another protocol", but SoftwareBitbang over one wire got my attention there.

It supports simplex and half-duplex asynchronous serial communication for up to 254 devices over a single wire. The maximum length of the bus can reach between 800 and 2000 meters depending on the mode used.

So you can easily do a three wire bus (PWR,GND,PJON-DATA) for your home.

[gryzli133]

I use PJON Software bit Bang as a communication protocol in my DIY smart home based on MySensors. It works extremly reliable since 2 years now. The Single gateway is connected to about 40 nodes, each of the node is about 10-40m cable. So the network has multiple hundreds of meters. No dropdowns, no restarts needed, completely care free. I have my DIY smart thermostats (BMW280+OLED+4 Buttons) based on Esp8266, but connected through PJON/MySensors. I switch WiFi just for OTA Updates. Would be nice to have this possibility also in ESPhome.

For Hard-wired freaks like me, the superb option would be to have a gateway based on ESP32 with Ethernet port that communicates with HA and get data from other esp through one single PJON-wire (Software Bit-Bang) to other nodes. Nodes would just use WiFi to OTA-updates - f.e. switched on by an virtual switch from HA.