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Topic: 3 wire load cell (Read 5627 times) previous topic - next topic

May 27, 2011, 02:17 pm Last Edit: May 27, 2011, 02:26 pm by pat_rice_irl Reason: 1
Hi All
I have a 3 wire load cell, Which I would love to use for a project to measure weight But Most load cells come with 4 wires, however, The ones I have found in my weiging scales are 3 wires, does anyone have any ideas on how I would connect them to a Arduino?

I have attached some Pics as I'm not very good at explaining this stuff. I have no datasheet for this, and the only marker I could see on the load cell was a 8964f. the PCB picture may shed more light on how this load cell was connected.

Load cell



Load Cell up close



PCB Circut



I'm wondering if the white wire is the signal wire and back and red are ground and power respecivley, any way you can test this? Just going off this blog post I've seen below.



or have I a load cell with an inbuilt amplifier?

http://www.electro-tech-online.com/general-electronics-chat/96880-3-wire-load-cell.html



This 3 wire load cell acts as a potentiometer. I also have the same 3 wire load cell and tried to connect the black wire to 5 v and red wire to ground. The white wire gave me about 2.5 v.
When I applied some force on it, the voltage changed so small. So maybe it doesnt have amplifier yet.

-fino

Thanks Fino

much appriceated for your answer, I have had this project sitting on the back burner for a while. I boutght a scales from www.lidl.ie in ireland, it was less then €20 so a cheap way of getting load cells :), I tought I might be able to hack it to the arduino, I wonder will the scales pic up the low voltages? or will I have to use an amplifier for it, and what one shoud I use?


just spotted this on google, hadn't been there when I put this post up :(

http://electronics.stackexchange.com/questions/18669/how-to-wire-up-a-3-wire-load-cell-strain-gauge-and-an-amplifier

It might hold some answers, Must have a read of it!

Thanks
Pat

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