LilyGO T-SimHat Expansion Board w/ CAN, RS485, Relay, DHT11, INA219

The T-SimHat is designed for direct stacking. Align the board's male headers with the corresponding female GPIO headers on your T-SIM7000, A7670, or A7608 development board and press firmly to seat the connection. Ensure the board is oriented correctly by matching the silkscreen labels. No external wiring is required for the primary interfaces, though you will need to connect external devices (like sensors on RS485 or loads to the relay terminals).

The onboard relay is a 1-channel (single-pole, double-throw) electromechanical type, typically rated for 10A at 250VAC or 30VDC. The screw terminal block provides three connections: Common (COM), Normally Open (NO), and Normally Closed (NC). To switch a load, connect one lead of your load to the COM terminal and the other lead to either NO (for closed circuit when relay is energized) or NC (for open circuit when relay is energized). Always ensure your load's voltage and current ratings are within the relay's specifications.

For the DHT11, use the Adafruit DHT sensor library. Define the data pin (consult the T-SimHat pinout diagram) and call `dht.readTemperature()` and `dht.readHumidity()`. For the INA219, use the Adafruit INA219 library. Initialize the sensor with `ina219.begin()` and read values using `ina219.getBusVoltage_V()`, `ina219.getCurrent_mA()`, and `ina219.getPower_mW()`. Both sensors communicate via dedicated I2C or digital pins that are pre-wired on the expansion board, so no external connections are needed.