Firmware Updates

Updating your WeSense sensor firmware is done by reflashing over USB using the Arduino IDE — the same process as the initial flash.

Before You Update

1. Keep a copy of your configuration — note your settings in credentials.h and wesense-sensor-firmware.ino (WiFi credentials, location, sensor settings, etc.). You'll need to re-apply these to the new firmware before flashing.
2. Pull the latest firmware from the wesense-sensor-firmware repository
3. Apply your configuration to the new firmware files — copy across your WiFi credentials, location, deployment type, and any other settings you changed from the defaults

Calibration data (e.g. CO2 sensor calibration that takes 7 days) is stored in NVS on the device and is designed to survive firmware updates. However, this capability is still being evaluated for reliability — see Firmware Configuration for details.

Flash the Update

1. Open the updated wesense-sensor-firmware.ino in Arduino IDE
2. Verify your Arduino IDE settings are correct (see Firmware Setup):
   • Board type matches your hardware
   • Partition Scheme set to Minimal SPIFFS
   • USB CDC On Boot enabled (C3/C6/S3 boards)
3. Connect your sensor via USB
4. Click Upload

The new firmware overwrites the previous version. Your sensor will restart automatically after flashing.

Verify It's Working

Open the Serial Monitor (115200 baud) and check:

• WiFi connects successfully
• MQTT connects to your configured broker
• All expected sensors are detected
• Readings are being published

Don't leave it on your desk too long

It's good practice to check the serial output for a few minutes to confirm everything is working. However, don't leave your sensor running indoors for more than about 5 minutes if it's configured as an outdoor sensor — it will start sending indoor readings (e.g. your warm office temperature) to the archive under your outdoor location. With enough nodes in a region the network can handle occasional anomalies, but if you're the only node in your area this will show as incorrect data. Flash, verify, and redeploy promptly.

Reconnect and Redeploy

Once you've confirmed the update is working:

1. Disconnect the USB cable
2. Return the sensor to its deployment location
3. Power it on — it will reconnect to WiFi and MQTT automatically
4. Check the live map to confirm data is flowing

Update Frequency

There's no fixed update schedule. Check the firmware repository for new releases. Updates typically include new sensor support, bug fixes, and protocol improvements. The firmware will never update itself automatically — you're always in control of when to update.