Layer: Foundation · Build flags: PC_ENABLE_SIGFOX

What this example teaches

The one radio that runs the opposite direction from the gateway examples. Instead of bridging a southbound radio northbound, the device itself uplinks a tiny message (<= 12 bytes, ~140 per day) over the Sigfox 0G network straight to the cloud - ultra-low-power telemetry from places with no Wi-Fi. A Wisol / Murata Sigfox modem is driven by AT commands over UART; the only hardware-specific code is the UART carry.

reading --pc_sigfox_build_uplink()--> "AT$SF=<hex>" --UART--> modem --> Sigfox cloud

modem reply --> pc_sigfox_parse_response()

services/sigfox is a pure AT-command codec:

uint8_t payload[4] = { ... };            // your reading, <= 12 bytes
char cmd[32];
uint16_t n = pc_sigfox_build_uplink(payload, sizeof(payload), cmd, sizeof(cmd));
Serial2.write(cmd, n);                    // "AT$SF=xxxxxxxx\r\n"
// then, over the modem reply:
pc_sigfox_result r = pc_sigfox_parse_response(buf, len);  // SIGFOX_OK / _ERROR / _PENDING

The payload is hex-encoded (uppercase, two nibbles per byte), and the response is classified as OK, ERROR, or still pending. The codec is host-tested in test/test_sigfox.

Wiring (ESP32 <-> Sigfox modem)

Modem	ESP32
TX	GPIO 16 (RX)
RX	GPIO 17 (TX)
VCC	3V3
GND	GND

9600 8N1. Needs a Sigfox modem and an active Sigfox subscription for the region to actually transmit.

Build-flag note

The flag must reach the library build, so pass it as a build flag:

pio ci --board=esp32dev --project-option="framework=arduino" \
  --project-option="build_flags=-DPC_ENABLE_SIGFOX=1" \
  --lib="." examples/Drivers/SigfoxUplink/SigfoxUplink.ino