Adapter Board

The Adapter Board sits between a Pierre Controller and one or more external DS18B20 temperature sensors. The controller supplies 5 V and a 5 V data line, while the sensors run from a lower regulated voltage. The board bridges the two domains and adds the protection a field-wired cable run needs.

It does three things. It protects — resettable overcurrent protection, reverse-polarity protection and overvoltage clamping on both the controller side and the sensor side, so a wiring fault out on the sensor run cannot reach the controller. It regulates — a local regulator derives the 3.0 V sensor supply from the 5 V input. And it translates — a bidirectional level shifter carries the 1-Wire data line between the 5 V controller side and the 3.0 V sensor side, providing the bus pull-up in both directions.

From the system point of view the board is entirely passive. It holds no microcontroller, no firmware and nothing to configure: it is powered by the controller and transparent to it, so sensors behave exactly as they would if wired directly.

Connections are made through two three-pole push-button terminal blocks, one at each end of the board, marked for supply, data and ground. An arrow on the underside shows the direction from controller to sensor. The board is supplied bare and must be fitted inside an enclosure.

• Connects DS18B20 1-Wire temperature sensors to a Pierre Controller
• 5 V DC input from the controller, regulated 3.0 V sensor supply
• Bidirectional 1-Wire level translation between the two voltage domains
• Resettable overcurrent protection on both the input and the sensor rail
• Reverse-polarity and overvoltage protection on both sides
• Passive design — no microcontroller, firmware or configuration
• Two three-pole push-button terminal blocks, marked for supply, data and ground
• Supports more than one sensor on the same bus
• Bare board — requires an enclosure