Arduino Farming Workshop

UART Input Format for companion_sensor_ble_uart_v2

Serial settings

• Baud: 9600
• Format: 8N1 (8 data bits, no parity, 1 stop bit)
• Pin: GPIO 47 on Heltec V3
• Logic level: 3.3V (NOT 5V tolerant)

Line format

MC,N=<node_id>,T=<temperature_c>,B=<battery_v>\n

• Lines must end with \n (newline). \r\n is also accepted (\r is ignored).
• All characters must be printable ASCII (0x20-0x7E). Lines containing non-printable bytes are discarded.
• Maximum line length: 127 characters.

Fields

Examples

MC,N=7,T=24.3,B=3.98
MC,N=100,T=-5.2,B=4.15
MC,N=0,T=0.0,B=3.30

What happens on parse

Each valid line immediately triggers a mesh send to the configured target gateway. The values are packed into a REQ_TYPE_SENSOR_UPLOAD (0x10) packet:

• node_id (uint16) from N
• temperature_x10 (int16, 0.1C units) from T — e.g. 24.3C becomes 243
• battery_mv (uint16, millivolts) from B — e.g. 3.98V becomes 3980

Arduino example (sender side)

Serial.print("MC,N=7,T=");
Serial.print(temperature, 1);
Serial.print(",B=");
Serial.print(battery, 2);
Serial.println();