Measuring Strain values with Strain Gauge

Hi there,

I want to measure the strain with strain gauges and found it should be connected as follows:

|500x172 My question is, what wires of the strain gauge do I connect to Red, Blk, Wht, Grn and Ylw? As I don't have coloured leads on my strain gauges and have to solder them on myself. Also, my strain gauges only have two connecting wires. Do I need to make my own wheatstone bridge with some resistors so I get 4 wires per strain gauge?

Cheers in advance for any help.

Where did the image come from ? Is there a sketch to go with it ?

UKHeliBob: Where did the image come from ? Is there a sketch to go with it ?

Hi, the image came from this website: https://theorycircuit.com/interfacing-load-cell-arduino-using-hx711/, as far as I can see there is no sketch of that circuit diagram.

Your strain gauges are just strain gauges having two wires. The link refers to a strain gauge bridge (strain gauge in Wheatstone bridge) configuration. You can either build a bridge starting with your strain gauge or buy a bridge. There is much more to it.

Ron

This is a pretty good place to do some self-education: https://www.hbm.com/en/7163/wheatstone-bridge-circuit/

Hi Ron,

thanks for the reply. So if I want to buy one what is a suitable one and if I want to make one what resistors would be best to use?

Cheers.

Multiplier7: Hi Ron,

thanks for the reply. So if I want to buy one what is a suitable one and if I want to make one what resistors would be best to use?

Cheers.

Depends on exactly what you want to measure. How much force and the configuration. The simple approach is just to buy a load cell designed for what you want to do. Ron

Multiplier7: Hi Ron,

thanks for the reply. So if I want to buy one what is a suitable one and if I want to make one what resistors would be best to use?

Cheers.

As above, depends on what you want to measure. Things can get complicated. Years ago I did quite a bit with strain using gauges made by Micro Measurements now a division of Vishay. You may find some of these videos useful. Pay attention to the adhesives used so you can choose what works best for you.

As to building a bridge? There are off the shelf basic solutions like this one but it is easy to build your own bridge. Depending on your gauge resistance all you need is several 120 or 350 Ohm precision 1% resistors. You need to also decide if you want a quarter bridge, half bridge or exactly what? A Google of Strain Gauge Bridge Circuits should get you plenty to read. You also want to get familiar with strain gauge "Gauge Factor".

Sometimes it is best if you can find an off the shelf solution, for example a load cell for tension or compression where all the work is done for you including temperature compensation.

Ron