CAN Bus interface and smart power supply board for custom gauges and other automotive projects.

Features

1. 6-position screwless terminal block.

2. NXP TJA1057 based CAN bus interface with 3.3V or 5V logic levels. Designed for microcontrollers with a built-in CAN bus peripheral (e.g. ESP32 TWAI).

3. Selectable 120 ohm termination resistor.

4. 5V, 500 mA Power supply with PTC fuse, reverse polarity and transient protection. Approximately 8-16V input range (18V max).

5. Prototype area for local circuitry.

6. Auxiliary signal brought to connector header.

Power to the user's application can be controlled by a variety of methods.

1. Always On : Power available whenever 12V power is available.

2. Automatically Switched : Switches on when automotive power rail goes above about 13.2V and off when it goes below about 13V. This allows the controlled device to be switched on when the car is switched on and the 12V battery charging is active and off when the car is switched off.

3. Remote Control : An external signal can control power.

Power consumption when switched off is nominally less than 100 uA.

The Auxiliary signal (AUX) may be used for any purpose. My intention with it is to allow connecting an external dimming signal to gauge circuitry for integration into a vehicle's existing systems.