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1046 PhidgetBridge 4-input & Strain Gauges

Posted: Fri Dec 02, 2011 12:04 pm
by ctm
Hi there,

We want to use strain gauges to measure the stress on an object. In order to read the measurements we thought of using the 1046 PhidgetBridge 4-Input.

However, it is not clear to us whether we can connect the strain gauge (which doesn't incorporate any wheatstone bridge) directly to the 1046 PhidgetBridge or whether we need a wheatstone bridge or similar in between.

1. Can we connect a strain gauge directly to the 1046 PhidgetBridge 4-Input?

2. Otherwise, would it work with a Voltage Divider (such as 1121 or 1134) in between?

3. Otherwise, what do we need to put there?

Re: 1046 PhidgetBridge 4-input & Strain Gauges

Posted: Fri Dec 02, 2011 12:33 pm
by fraser
For the 1046, you would want to use a strain gauge in conjunction with a wheat-stone bridge. You can do this by replacing one of the 4 resistors on a wheatstone bridge with the strain gauge; and then connecting the wheatstone to the 1046 as described in the product manual.

We will, at some point in the near future, be selling through-hole resistors that can be used in a wheatstone bridge.

Re: 1046 PhidgetBridge 4-input & Strain Gauges

Posted: Fri Dec 02, 2011 12:44 pm
by erik
Additionally, strain gauges typically have very small changes in resistance when stressed. The voltage dividers will not be able to accurately pick up the changes.

Re: 1046 PhidgetBridge 4-input & Strain Gauges

Posted: Thu Dec 22, 2011 6:03 am
by ctm
Hi again,

Although it's been a while, just to mention that the setup with the wheatstone bridges and the 1046 4-Input bridge worked just fine :)

For reference, we wired it as shown in the first circuit of this PDF

Thanks for everything!