Calibration

Calibration turns the raw value read by the HX711 into a usable weight.

Bee Thing stores two values in runtime configuration:

• hx711.scale_factor: conversion factor;
• hx711.tare_offset: tare offset.

Principle

The HX711 does not directly measure kilograms. It provides a raw value that depends on the load cell, wiring, mechanical build, and how force is applied.

Calibration must therefore be done on the final build, or at least on a mechanically representative setup.

Recommended Method

1. wire the load cell and HX711;
2. install the load cell in a stable position;
3. start the board in configuration mode;
4. set tare with no useful load;
5. place a known weight;
6. adjust the calibration factor;
7. save configuration;
8. send a first measurement and verify the result in Bee Thing.

Useful Commands

bee-config set hx711.scale_factor "1234.5"
bee-config set hx711.tare_offset "42"
bee-config validate
bee-config save
bee-config run

Watch Out For

• a poorly constrained load cell gives unstable measurements;
• tare done before the final mechanical build can become wrong;
• a test weight that is too light can hide errors;
• cables and connectors must remain stable after installation.

Exact calibration depends on the physical build. This page does not replace validation with a known weight.