Notes for the schematic:
- The OP-AMP has the wrong part nr, we use OPA337 but I couldn't find that one in Eagle.
- The relays also has a wrong part number.
- The circuit does not show that the site connectors also should have +5 and GND connected to the (only the 1-wire data cable, OW)
- The LCD display has the wrong part nr, but it follows the Hitachi HD44780 standard