Some questions about the HX711 Calibration program

Sensors Force & Weight
1

Hello,

I am running the “SparkFun_HX711_Calibration.ino” obtained from:

https://learn.sparkfun.com/tutorials/lo … okup-guide

I have the S Load Cell sitting on a desk. The weight of the object used for calibration is 1.459kg but as I put it on the S Load Cell, the Serial Monitor shows 3kg. Am I supposed to keep pressing - and return alternatively until the serial monitor shows 1.459kg? So far, I have to keep pressing these two keys many times to reduce the reading by 0.1kg. Is there a faster way to do it?

Is one decimal accuracy sufficient for the HX711? If I use g, I will need to keep pressing - and return impractical number of times.

Also, with the S Load Cell sitting on a desk and no load above it, the readings from the Serial Monitor shows 0.0 kg or -0.0kg. Do I need to worry about the sign in the no load case?

2

Pressing the keys to adjust the value can be tiring. You can modify the code to allow larger increments with a single key press. Seeing 0.0 kg or -0.0 kg in the no-load case is normal.

3

If you can’t access the code for some reason, you could make another calibration object with something easy to adjust like a resealable 2 liter beverage bottle. Add water or sand to the empty bottle to make up the remaining 1541 grams and use it for testing, cal adjustment, etc.

The sign changing is probably just rounding due to normal and expected drifting within single graduation representing 0.1 kg. You could test this by changing the resolution to something greater like 1 kilogram and watch the zero polarity within the larger window.