I'm new to this field and have a question about using a strain gauge load cell and its amplifier. I have a commercial weighing scale that can measure weights from 0.001g to 500g. It works well, but when I opened the scale and connected its load cell to my HX711 amplifier and Arduino Uno, I'm getting unstable weight readings - the weight keeps changing. The same load cell works fine with the commercial scale board, but not with my Arduino setup.
Could the problem be due to input voltage issues, or is it because of a poor quality HX711 amplifier? I'd appreciate your guidance and suggestions on how to make my weight project stable. Thank you!
That is one of many potential problems. Lead dress, circuit design, power sources etc. Post an annotated schematic showing exactly how it is wired, show all connections, power, ground, power sources and note any leads over 10"/25cm in length. Show all devices and post links to technical information on them.
It could be your software as well but generally I find it in hardware. I doubt it.
Get the data sheets of the Load Cell used in your Scale and find the voltage that the Load Cell produces when the input load/weight is 1 gram (I think that it is at micro-volt level). Certainly, you need very high-gain/low noise amplifier and 32-bit/24-bit ADC to convert such micro-volt level signal into binary. The HX711 Module contains a x64 amplifier and a 24-bit ADC.
The following article describes some of the challenges of load cell design and contains some suggestions. But a 500g scale with 0.001 g resolution is going to be a BIG stretch for a DIY-er. Virtually impossible, I'd say.
Edit to add: if you really need that kind of performance with an Arduino involved, you'd be miles ahead if you buy a commercial scale that has RS232, I2C, SPI, or similar digital output.
It would be helpful if you said which Arduino and where you bought the HX711. And post a photo of the HX711.