ESP-IDF firmware for a battery-powered ESP32-C3 hive scale. The project is an ongoing prototype focused on reliable measurements, offline storage and a weather-resistant mechanical frame.
Early bench prototype used to test load distribution across four load cells.
Load cells -> HX711 -> ESP32-C3 -> MQTT -> Node-RED -> InfluxDB -> Grafana
The ESP32-C3 reads the load cells through an HX711 amplifier and publishes the measurements over MQTT. Node-RED receives and routes the data, InfluxDB stores the time series, and Grafana presents it. The integration implementation saves measurements to NVS before attempting network communication, so unsent data can be retained during a connection outage.
Early test measurements presented in Grafana through the NIG stack.
ESP32-C3, HX711 and battery supply assembled for bench testing.
Temporary frame and test loads used while evaluating measurement stability.
The wooden frame is only a test fixture. The next step is a weather-resistant frame that transfers the hive's full weight through the load cells while protecting the electronics from moisture.
- Seeed Studio XIAO ESP32-C3 with 4 MB flash
- ESP-IDF 5.5.x (the release workflow uses 5.5.2)
- A 2.4 GHz Wi-Fi network
OTA release binaries do not contain Wi-Fi credentials. The first local build seeds credentials into NVS, where subsequent OTA firmware reads them.
- Copy
main/config.example.hto the ignored filemain/config.h. - Set
WIFI_SSIDandWIFI_PASSinmain/config.h. - Load ESP-IDF 5.5.x in your shell.
- Build the firmware with
idf.py build. - Connect the board over USB and run
idf.py erase-flash flash monitor.
The erase is required when moving from the original single-app partition table
to the dual-slot OTA partition table. It also ensures stale PHY data cannot be
mistaken for OTA selection data. Keep main/config.h private.
After the first successful boot, the device stores the credentials in the NVS
partition. Normal OTA updates preserve that partition. To replace credentials,
update main/config.h, erase flash, and repeat the bootstrap flash.
After receiving an IP address, the device checks this HTTPS endpoint:
https://github.com/fransstrom/hive-scale/releases/latest/download/beescale.bin
The server certificate is validated with ESP-IDF's trusted certificate bundle.
The image header is fetched first; the full image is downloaded only when its
semantic version is newer than the running firmware. Release versions must use
the vMAJOR.MINOR.PATCH format. A completed update is validated, written to the
inactive OTA slot, and booted after a restart.
Bootloader rollback is enabled. A newly installed image is marked valid only after it starts and receives an IP address. If it resets or enters deep sleep before that checkpoint, the bootloader restores the previous image. A temporary Wi-Fi outage during the first boot of a new image can therefore trigger a rollback by design.
CONFIG_BEESCALE_OTA_CHECK_INTERVAL_WAKEUPS controls the interval. It defaults
to 1, so the current development setup checks on every wake. Because the scale
sleeps for one minute, change this line in sdkconfig.defaults for daily checks:
CONFIG_BEESCALE_OTA_CHECK_INTERVAL_WAKEUPS=1440
If a local sdkconfig already exists, make the same change through
idf.py menuconfig or regenerate it before building.
The GitHub repository must be public so devices can download release assets without embedding a GitHub credential.
The release workflow builds and publishes beescale.bin whenever a version tag
is pushed. The tag becomes the firmware version used for update comparisons.
git tag v0.1.0
git push origin v0.1.0Do not reuse a tag for different firmware. Create a new version tag for every
release, then verify that the GitHub release contains beescale.bin.
Project settings are under BeeScale Configuration in idf.py menuconfig:
- Firmware update URL
- Wake cycles between OTA checks
- Wi-Fi connection timeout
The flash layout uses ota_0 and ota_1 application partitions of 1700 KB
each. The application must continue to fit in that limit.