Weight measurement using load cell adn HX711 module

[shweg]

The output values when I place known weight of 173gms:

Load_cell output val: 9944383.00

Load_cell output val: 9944380.00

Load_cell output val: 9944356.00

Load_cell output val: 9944349.00
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The output values when I take the weight off:

Load_cell output val: 9944729.00

Load_cell output val: 9944729.00

Load_cell output val: 9944717.00

Load_cell output val: 9944532.00
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Load_cell output val: 9948243.00

Load_cell output val: 9948434.00

Load_cell output val: 9948446.00

Load_cell output val: 9948509.00

[shweg]

My circuitry is as follows:

Connections are made as per the diagram attached in my 1st post of this topic.

[GolamMostafa]

Your load cell is not responding. First check the functioning of the HX711 ADC Module. Check that there is about > 4 V between E+ and E-.

[DaveX]

Agree.

Those raw reading differences are nowhere close the the maybe 50000 count difference I calculated that you might expect. The first few unloaded readings differ from the loaded readings by about 300, and then the last few unloaded readings are about 4000 higher. Maybe there's a bad connection delivering garbage into the HX711, and then it's all GIGO downstream from there.

A good multimeter could help diagnose whether the fault lay in your connections or your gauge.

[shweg]

Is mounting of load cell on wooden board/platform necessary?

[DaveX]

The cell works by bending the crossbar between the outer ring and inner ring, and measuring how much the top surface of the bar stretches and contracts. It is a cheap version of a Z-bar load cell.

If the bar or inner ring is sitting directly on a surface, it won't bend, won't stretch, and won't change resistance much with load.

It does need support on the outer ring so that the inner ring can deflect. See post #20: Weight measurement using load cell adn HX711 module - #20 by GolamMostafa