Using multiple load cells

Other Hardware Sensors
1

Hi there,

I'm trying to use components found in a digital scale to interface with an Arduino in order to measure the weight of a human.
After some research, I found that by using an INA125P amplifier I would be able to get an accurate reading from a load cell.

The hard part comes where I have 4 load cells at my disposal to use. I'm assuming each of them only takes about 50kgs, and i'll need to weigh at least up to 150kg's. The load cells only have 3 wires each. I think that means they are half bridge? I'm really not entirely sure.

Basically I just need a bit of help or guidance about how to connect them all for use with the Arduino, preferable not by just measuring the output from the PCB already in use by the scale.
Is there perhaps a circuit diagram for this sort of connection? I've been searching for hours and every thread I find or internet page I find doesn't seem to quite fit my problem.

Thanks in advance :slight_smile:

2

The INA125P is expensive and only half of what you need for precise readings. It amplifies the signal (stably!) but unless you use it in combination with another AD converter you'll only get the 10 bits of precision that the Arduino can provide. The ADS1231 for a full bridge (or ADS1232 for two bridges) with 24 bits of precision is a better choice but there are other options depending on how precise you need your readings.

With respect to how to wire them you need to provide more detail on what you're trying to do and a better description (picture?) of the strain gauges you have. Typically these are using in pairs to form a wheatstone bridge as you suspected but that's not required.

3

Hello, Could you share the code for the ads1232 with Arduino loadcell reading, I saw a post that could make reading, need to do a project and I'm having difficulty.