Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [strain-gage]

A strain gauge measures the physical strain on an object. The most common types are a metallic foil attached to a flexible backing where the resistances changes when subjected to compression or tension.

108 questions
11
votes
2 answers

Should we use wheatstone bridges nowadays?

For measuring strain gauges, the Wheatstone bridge is the historical choice. In a quarter Wheatstone brigde (\$350 \Omega \$ typically (?)), with a high input impedance amplifier, and some bridge power voltage \$V\$, the ratio between the bridge…
Brethlosze
  • 1,409
  • 11
  • 32
7
votes
4 answers

Wheatstone bridge sensitivity and accuracy

From my earlier question I was able to wire up 2 SEN-10245 weight sensors (each forming one half of a wheatstone bridge) with an AD620 InAmp & 47 Ohm resistor (to set the gain to ~1000). I then ran the signal through the MCP3008 Analog to Digital…
Anconia
  • 183
  • 2
  • 6
6
votes
3 answers

Is the Excitation Voltage of a load cell a strict specification?

When using load cells (or strain gages generically), is the Excitation Voltage spec provided as a strict minimum -- or is it just a recommendation which one can go below as long as one is OK with a smaller full-scale output? The details: I wish to…
boardbite
  • 4,892
  • 11
  • 47
  • 73
6
votes
4 answers

What kind of a sensor does a arcade punch (boxing) machine have?

I am working on a project, where I have to measure the pressure exerted by a punch. I am trying to understand how an arcade machine works, and see if I could replicate the same mechanism in my project. Additionally, I would like for the sensor to be…
hegemon8
  • 95
  • 2
  • 7
6
votes
1 answer

LM324 op-amp wheatstone bridge amplifier formula

I'm planning to use an LM324 opamp as a signal amplifier for a cell load (strain gauge in a Wheatstone bridge). This particular application is shown in the datasheet (see image). It shows the Wheatstone brige (bottom-left resistor is the strain…
dodod
  • 137
  • 1
  • 9
5
votes
4 answers

devices for measuring tension or detecting "slackness" in fishing wire

How might I go about measuring the tension in a line of fishing wire? I'm mostly interested in determining when the line is in tension vs when it's slack. The application is a boat-mounted depth-finder. A weighted line could be lowered into the…
Matt
  • 231
  • 2
  • 10
5
votes
2 answers

Load Cell Amplifier AD620

I know AD620 is an old part but it is available at my place. I intend to develop a Load Cell amplifier. Load cell is 2mV/V. I am planing to use AD620 for it. Following are my calculations: Excitation Voltage for Load Cell = 5V Full Scale for load…
Lagrangian
  • 235
  • 4
  • 9
5
votes
2 answers

How to Read Wheatstone Bridge negative voltage with Arduino?

I have a half bridge setup with strain gages and a INA126 to amplify the voltage. I can read the voltage fine when the lever is bent one way, but when beding the lever in the opposite direction I don't get any reading. I'm guessing it's because…
criverapr
  • 151
  • 1
  • 3
4
votes
4 answers

Strategy to balance a Wheatstone bridge for strain measurement

The purpose of my project is to build a sufficiently accurate "Strain indicator" based on the use of a Wheatstone bridge using an Arduino. Currently I am using a HX711 as load cell amplifier which is working well since I use it with a full…
Guuk
  • 141
  • 1
  • 3
3
votes
2 answers

Weird reading from NAU7802 ADC

I'm using an NAU7802 ADC which has a built in amplifier. I'm trying to use it to read a strain gauge but it keeps giving me weird readings. Eventually I resorted to shorting the two differential inputs together so that it should read 0, however…
Timmmm
  • 1,133
  • 2
  • 14
  • 18
3
votes
3 answers

Creating a Strain Gauge Load Cell

I want to make my own load cell; how specific do the materials need to be? For example, is it necessary to buy all the cleaning and gluing equipment shown in strain gauge installation videos? Or can I just scrub the surface, rinse & dry it clean,…
kenntnisse
  • 299
  • 8
3
votes
1 answer

Instrumentation opamp saturating

I'm building a circuit to measure signal out of a wheatstone bridge for strain gauge. here is the schematic: simulate this circuit – Schematic created using CircuitLab I applied +-1.5V with digital power supply and measured the output with Arduino.…
cola chicken
  • 63
  • 5
3
votes
5 answers

Instrumentation amp giving only positive output (with + and - power supplies)

I'm using an instrumentation amp for a bridge circuit for strain gauges. However, the output range is always positive (the lowest value I can get is zero). The amp I use is AD620. For power supply I used two 9V batteries to get the +-9V. Is there…
cola chicken
  • 63
  • 5
3
votes
2 answers

How does full wheatstone bridge with strain gauges work?

I have gone through a number of tutorials on Wheatstone bridge and how to use it to sense load using strain gauges. I have also gone through the calculations where one of the resistors of the Wheatstone bridge is a strain gauge and how the voltage…
Shishir Pandey
  • 133
  • 4
3
votes
3 answers

How do I use this Strain Gauge sensor?

The load cells here: http://www.cnloadcell.com/mlc700-postal-scale-load-cell and here: http://www.cnloadcell.com/mlc714n-personal-scale-weight-sensor have 4 wires (red, white, black, green). The diagram is quite confusing, I think I can see it is…
Blundell
  • 161
  • 2
  • 11
1
2 3 4 5 6 7 8