Weight scale IoT by ESP32

Fig.1 shematics by Fritzing

Fig.2 The weight scale remodeled by ESP32-HX711-MTT

Legacy weight scale is remodeled into WiFi connected scale by ESP32

• The original control board with LCD is removed. Load cells and push button of the scale are re-used.
• ESP32 sends weight to MQTT server at port 2883.
• Node-RED on raspberry pi splits incoming MQTT at 2883 to Thingsboard at port 1883 and "slack" node to inform to my mobile phone.

Fig.3 slack

Fig.4 Node-RED running on raspberry pi

remaining issues

• sometimes WiFi reconnection fails after wake up from deep sleep

License: Apache License v2

References

• [AVIA Semiconductor HX711 data sheet]https://www.mouser.com/ds/2/813/hx711_english-1022875.pdf
• [https://github.com/bogde/HX711] https://github.com/bogde/HX711
• [HX711 library for ESP32]https://github.com/SensorsIot/Weight-Sensors/tree/master/HX711
• [#161 Measuring weight using an ESP32, a strain gauge, and a HX711]https://www.youtube.com/watch?v=iywsJB-T-mU
• [#194 IKEA Saltviken Scale Hack: Create a 150kg Scale Connected to Google Firebase (ESP32, ESP8266)]https://www.youtube.com/watch?v=14YmiEycup4

PubSubClient

• https://github.com/knolleary/pubsubclient

MQTT server with visiualization tools

• [https://thingsboard.io/] (https://thingsboard.io/)