Arduino uno with Load Cells

Other Hardware Sensors
1

Hi All,

I am trying to build a circuit with a 3 load cells, 3 spark-fun load cell amplifier and Arduino uno. I initially connect one load cell and amp board and ran a sketch to check if my code and components worked and I was able to calibrate the load cell and get some results .

I have tried to connect a second load cell and the Arduino seems to not turn on at all. I believe all my connections are correct and there are no tpjbelms with the uno. Each amp board have separate data lines on the uno but share the same clock lines and the VDD connects to 3.3V port and the VCC connects to the 5V. Why is the Arduino not turning on in the configuration. Can it not handle 2 load cells? Can I get some help please?

Load cell using : https://uk.rs-online.com/web/p/strain-gauges/8937398/

Amplifier board: SparkFun Load Cell Amplifier - HX711 - SEN-13879 - SparkFun Electronics

Using with a standard Arduino uno Rev 3

Thanks

2

Must be your wiring, or soldering, an UNO can handle 3 HX711s no problem.

3

adam272000:
the VDD connects to 3.3V port and the VCC connects to the 5V.

Yes on a 3.3volt processor, but not on an Uno (5volt logic).

Both VCC and VDD of the HX711 must connect to 5volt.
Leo..

4

missdrew:
Must be your wiring, or soldering, an UNO can handle 3 HX711s no problem.

Thanks , I believe it is my wiring

5

Wawa:
Yes on a 3.3volt processor, but not on an Uno (5volt logic).

Both VCC and VDD of the HX711 must connect to 5volt.
Leo..

Perfect, thanks this must be the problem. So to confirm at the VCC and VDD outputs (6 total from 3 amp boards) must be all be wired to the 5V ?

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No I don't think wiring VDD to 3.3volt is the problem, but it's wrong for the 5volt logic of an Uno.

Yes, wire all six HX711 power connections to the 5volt pin of the Uno.
If you're not sure, then post a picture of the setup, and the code (inside code tags).

If you use a 3.3volt processor, like a Due or the newer MKR boards, or an ESP WiFi board,
then all VDDs must connect to 3.3volt and all VCCs must connect to 5volt.
Leo..

7

Hello,
Try also separate clock lines. I think your problem is there.
Clock signal is generated by the lib, if you connect them all togehter, the scond instance of the HX processing object will receive the clock signal of the first. As they are not in phase, you risk problems.
Best Regards;
Johi.

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