Hello,
I'm trying to use a strain gauge to measure forces. It is interfacing with a DC Amplifier. The DC amplifier has in+,in- and out+,out-. If I wanted to read values to the Arduino, would I connect out+ and out- to pin A1 & A0, then code the Arduino to subtract the signal coming from A1 & A0 to get voltage?
Or would I just ground out- and connect out+ to pin A1.
Thank you
We need more information on your 'DC Amplifier', such as make and model number, or a link to it's datashee,t. to give you the correct answer.
Grounding out- may be detrimental, if it is not meant to be grounded.
Just google - wheatstone bridge arduino
It’s not so simple because a bridge can have a positive or negative output. This depends on the direction of deflection and the orientation of the connections. The larger issue is that an Arduino cannot handle a negative input voltage which will occur in 50% of your use cases.
The simplest solution is to use the HX711 strain gauge amplifier as its output is digital, not analog. This chip is the most common way to interface a strain gauge with an Arduino. A quick google search will lead you to suppliers (vast and cheap) and the required Arduino libraries.
JohnLincoln:
We need more information on your 'DC Amplifier', such as make and model number, or a link to it's datashee,t. to give you the correct answer.Grounding out- may be detrimental, if it is not meant to be grounded.
The DC amplifier I'm planning to use is this one.
https://www.omega.com/pptst/OMNI-AMPIIA.html
ted:
Just google - wheatstone bridge arduino
I agree and did google. Most of the tips and suggestions told people they needed to amplify their signal because they used the wheatstone bridge configuration for strain gauge measurements. I am also using it to measure strain on a strain gauge.
avr_fred:
It’s not so simple because a bridge can have a positive or negative output. This depends on the direction of deflection and the orientation of the connections. The larger issue is that an Arduino cannot handle a negative input voltage which will occur in 50% of your use cases.The simplest solution is to use the HX711 strain gauge amplifier as its output is digital, not analog. This chip is the most common way to interface a strain gauge with an Arduino. A quick google search will lead you to suppliers (vast and cheap) and the required Arduino libraries.
Great point. I didn't think about the arduino receiving negative voltages.
I tried using the HX711 strain gauge amplifier with a 10kg load cell but had a lot of trouble finding the calibration factor. In the end I wasn't able to find the calibration factor and tested each component and the problem was I didn't know how to interface the HX711. This project of mine is for school and I don't have too much time so I wanted to just use the DC amplifier to send voltage to the arduino so the arduino could record the voltage.
Thank you all for your replies.
Google again - Wheatstone Bridge op amp - output of op amp to analog input arduino, the program - arduino voltmeter.
Hi,
What is the strain-gauge that you are using, link to data/spec?
What is the application?
Did you use a library with the HX711?
Thanks.. Tom.. 