ESP-KVM is free, open-source firmware that turns an ESP32-P4 board into an IP-KVM: another computer's screen, keyboard and mouse in your browser, from the BIOS up. The DS3231 module for the Raspberry Pi is an optional extra: a battery-backed clock that keeps the time across a power cut. What it does → Try the demo →
The small one with a soldered-on coin cell and a five-pin socket. On a board with a Raspberry Pi header it plugs straight onto pins 1-9.
| Status | Run on hardware |
|---|---|
| Chip | DS3231, at 0x68 |
| Socket | five pins marked + D C NC -, Pi header pins 1, 3, 5, 7, 9 |
| Wiring | on other boards 3V3, GND and the capture board's SDA and SCL |
| Battery | soldered-on coin cell |
| Setting | found by itself; Settings → System → Clock |
This is the one I run on my Function EV. It sits on the capture chip's I2C bus, so it needs no pins of its own. The device finds it at start-up and sets its clock from it, and writes the time back when it learns it from NTP or a browser. I pulled the power cable several times, and each time the clock came back within a second.
Diagnostics also shows the chip's thermometer, as the temperature by the board. Home Assistant gets it as a "Board temperature" sensor.
