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.

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54 views

AD7730 calibration failure

EDIT: The exact issue is this, the ADC has a gain register (set during internal FS calibration and again at System FS calibration) and an offset register set during system zero calibration. The ...
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2answers
50 views

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 ...
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1answer
59 views

Why is my amplified strain gauge output so unstable?

I've attached a strain gauge to a bending arm of a robot, and it varies by about 1.5 ohms from 356 to 357.5 ohms. I place this in a whetstone bridge. The strain gauge is R3. R1, R2, and R4 are all ...
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Any problem with this strain gauge configuration to increase resolution?

I'm new to using strain gauges, but I've seen the typical 1, 2, and 4 strain gauge wheatstone bridge configurations. Using the diagram below, I'm referring to where R3 is a gauge, or R3 and R4, or all ...
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58 views

Low current strain gauge

I am trying to make a low power device (based of RSL10 bluetooth SoC) that would sample a strain gauge @1kHz and transmit the measurements. The current drawn by the running SoC is about 1.5mA, while ...
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27 views

Wire shield when using connector for strain gauge sensor

I have made strain gauge sensor with 1 strain gauge. Thet gauge is in "bottom" part of Wheatstone brigde (one strain gauge terminal is signal, second is connected to ground). I'm using Sommer CICADA ...
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1answer
31 views

How to estimate force caused by a strain in a material from a strain guage?

So, I am learning about how strain gauges work and I understand that through stretching or compressing resistance of the staring gauge can be changed which can be measured in resistance accurately ...
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1answer
53 views

When is one active and one dummy strain gauge preferred to two active strain gauges?

As far as I understand, one active and one dummy strain gauge arrangement can be used for temperature compensation. But even two active strain gauges can be used for temperature compensation, and in ...
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1answer
73 views

Read data from strain-gauge Labjack, Arduino

I am working on a project where we have to record breathing data. For that we ordered a LabJack U3-LV along a with an amplifier (datasheet) and a belt which is some kind of strain gauge I think. We ...
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1answer
149 views

Strain gauge amplifier - so much noise!

I'd like to use atmega328p to read force with strain gauge. I'm using one 1k strain gauge and 3x 1k ohms dummy resistors. My circuit looks like that: I'm using DAC to remove offset from bridge. As ...
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1answer
55 views

Remove bridge offset before ICF amplifier or at FB pin?

I'm making project where I would like to read from stain gauge sensor. It will use only one 1k ohm (or 350 ohm) strain gauge and 3 dummy resistors to complete bridge (1k or 348 ohm). I'd lik to feed ...
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1answer
87 views

Wheatstone Bridge - strain gauge sensor

I'm trying to optimize a Wheatstone bridge with a strain gauge sensor and I'm considering all possible wire resistances. The circuit is shown in the following figure: I don't understand the comment ...
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1answer
210 views

What adhesive is best to glue strain gauges to metal?

I'm trying to use these strain gauges to measure bending of a metallic cantilever (metal TBD). Does anyone know what adhesive I can use to glue the strain gauges? I'd rather not have to use an oven ...
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1answer
78 views

in-amp for strain gauge

I'm working on a project where I should send an overload signal if the strain is bigger than 40 ppm. So far I found this answer: Strategy to balance a Wheatstone bridge for strain measurement The ...
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1answer
1k views

How does temperature compensation work for strain gauge in wheatstone bridge

Wheatstone bridge is used for temperature compensation for strain gauges If 2 strain gauges are connected like this figure. Due to temperature variation; the resistance Rg will change in the same way....
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2answers
189 views

What's the difference between consumer and industrial grade strain gauge adhesive? [closed]

Can I just use normal super glue and epoxy resin to attach a strain gauge?? What am I sacrificing by doing so? Also, how are load cells so cheap and what kind of adhesive / covering do they use?
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How much power does a strain gauge use?

Is it essentially nothing given how small they are? I see most configurations are given 5V, but does that mean they draw amperage as well?
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322 views

How to reduce noise in strain gauge measurements

I have two strain gauges on a 1 m length wind turbine blade which will rotate at 800 RPM. The amplifier and DAQ system will rotate with the blades. I'll have relatively noise environment and the ...
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1answer
74 views

Error in the gain, Amplifier, DAQ system

I have a strain gauge with maximum output of 5mV. I want to amplify this signal 1000 times in order to use my DAQ system to read it (the analog input range is 0-5V for DAQ connector). I have ...
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1answer
281 views

Compensating for offset voltage in bridge measurement before instrumentation amplifier

I'm using an instrumentation amplifier (INA118) to measure the signal from a full bridge strain gauge (tension only, all 4 resistive elements are strain gauges, slow changing (DC) signal). I'm using a ...
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1answer
2k views

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 ...
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1answer
196 views

TrackPoint a.k.a pointing stick 2-axis force sensor

I have an application that would benefit from a sensitive two-axis force or bending torque measurement very much like what a pointing stick (a.k.a. TrackPoint) used to do in a ThinkPad, apparently ...
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3answers
849 views

How do I use this Strain Gauge? (4 wire)

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 ...
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2answers
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how to connect strain gauge to HX711 module

I need get strain gauge reading to Arduino. so far i have found load cell Wheatstone configuration circuit here 3rd answer. I need to know if i connect a strain gauge to one +Active resistance, and ...
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1answer
140 views

ACAM PS09: Strain Gauge Stress Analysis

I've been working on implementing strain gauge measurements at my company for some stress analysis. There's a chip that I think works the best for our application. It's the PS09 by ACAM. However, ...
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4answers
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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 ...
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1answer
73 views

Force sensor on uneven shape

I'd like to measure the force that a human leg impacts on a knee brace during normal gait. I have a problem in finding a suitable sensor for the job... The leg (and hence the brace) are not flat at ...
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3answers
1k views

4 Wire Strain Gauge to 2 Wire Conversion/Connection

I have the WK-06-12BT-350 ohm WK125BT Strain gauge from Vishay the Gauge comes equipped with 4 wires ( High endurance lead wires). The following document describes a similar gauge: Strain Gauge is it ...
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0answers
352 views

Load cell circuit does not work on circuit simulator

I want to simulate a load cell interfacing with AD620 for amplification. - My load cell is 40 Kg max with 2mV/V sensitivity and 10 V excitation voltage with input resistance of 405 ohm and output ...
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3answers
1k views

A question about choosing, implementing and placing a strain-gauge amplifier

This will be a little long question. Since I was and still am alien to some concepts, I will go step by step. Basically it is about implementing a strain-gauge amplifier and wiring configurations for ...
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1answer
69 views

A question about amplifying low level strain gauge voltages

I'm having difficulty in deciding about implementing an amplifier and whether I need it at all for a strain gauge. I never dealt with such situation before and would be very glad to have your opinions....
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1answer
1k views

INA125P Strain gauge amplification problem

I'm using the INA125P to amplify the strain of a 350 ohm strain gauge in a self-built Wheatstone bridge circuit for measurement. I'm testing using a 351 ohm resistor to mimick a strain gauge under ...
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5answers
487 views

Measuring weight on a gym machine [closed]

We're doing a school project where we have to measure weight on a fitness machine. The user can select how many weight plates to use by moving a rod like shown in the picture. How would you do it? ...
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1answer
107 views

Voltage jump in time series data acquisition

This might be a basic question, but I am a Mechanical Engineer and hence stumped. I am acquiring (output) time series data from Strain gauge (excited by amplifiers). Attached plot is the output (ADC ...
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2answers
346 views

Copper Strain Guage

My understanding is that strain gauges are constructed using Constantan etched onto a flex PCB. According to wikipedia Constantan is highly suitable strain gauge material due to its high gauge factor. ...
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1answer
116 views

Negative differential to instrumentation amplifier causing problems

I am using a pair of strain gauges to make a weight scale. The strain gauges are the three-wire type that you can by on Amazon or Sparkfun. The strain gauges form a full wheatstone bridge, whose ...
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1answer
515 views

Strain Gauge - Wheatstone bridge DRIFT

I have a 350 ohm bridge with 04 fixed resistors, later on one of them will be replaced by a strain gauge sensor. In the meantime I am trying to understand where the drift is coming from. This bridge ...
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263 views

Measuring the angle of finger joints

I'm working on a project where I want to very accurately (+/- 1 degree) determine the angle at which a finger is bent. One of my main constraints is that my sensing mechanism can't interfere (much) ...
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3answers
271 views

Strain Gages Measurment Error and Saturation

I have an experiment composed of 16 strain gages, mounted on a steal beam. The steal beam is horizontally placed under a compression cylinder for a stress test. the test took around two hours to ...
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3answers
1k views

Wheatstone bridge offset

I have a Wheatstone bridge but I don't know the values of the resistances in it. My excitation voltage is 5 V. But instead of having 2.5 V on each output lines I get one line at 3.3 V and the other ...
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1answer
483 views

Measuring touch-weight resistance in piano keys

Piano technicians, such as myself, use an old, labor intensive way of measuring touchweight resistance in piano keys. I would like to automate this process electronically. This is an explanation of ...
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2answers
4k views

How many newtons could this BF350-3AA strain gauge support?

I am planning to purchase a strain gauge, the BF350-3AA in particular although there is no mention of how much force it is able to withstand. Also if someone could advise me of other strain gauges. ...
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1answer
303 views

Which one is the better way to feed analog input to my ADC?

I am planning to use an AD7730L analogue to digital converter (ADC) chip, with a quarter bridge circuit. Everything was on the track until I realised something, which indicated that things were ...
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1answer
2k views

Maximum sensitivity of a wheatstone bridge [closed]

Four strain gages are placed on an elastic element in order to measure axial force and moment. Assume that element cross-section is square with area, A = h2 . The strain gages all have the same ...
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3answers
879 views

The best way to trim a wheatstone bridge digitally?

I am building a Wheatstone bridge for strain gauge measurement. Due to component deviations a wheatstone bridge will often show an offset which needs to be trimmed: If we assume that we're using 5% ...
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1answer
671 views

Unstable voltage output for strain gauge application

I am doing a half bridge strain gauge application and it is connect to INA125P and with gain about 185 with Rg 330 ohm.below is my theoretical circuit diagram, my circuit is base on this picture to ...
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1answer
1k views

Non-zero output from a LM741 in a differential configuration

I'm trying to amplify a DC voltage coming from a strain cell (with a built in Wheatstone bridge). The voltage swings from -1mV to about 4mV depending on the strain. I've set up a differential ...
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66 views

Why does this seem like a strange way of connecting a bridge circuit to the ADC?

I was planning to hook up a quarter bridge circuit to the AD7730LBR Analogue to Digital Converter that I bought. I was having a look at a "Load_Cell_Schematic" provided by this webpage (the download ...
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2answers
691 views

Using DAC to create reference in a wheatstone bridge for strain gauge?

I am designing a circuit where a microcontroller can measure the load forced upon a load cell with strain gauges, making a half bridge. A traditional Wheatstone bridge looks like this: Resistors ...
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2answers
3k views

What does a strain gauge amplifier do?

I was at a placement for the last few weeks, and a lot of people were talking about a strain gauge amplifier. It was a box (the box was about 10cm x 8cm, 3D printed) although I didn't get to open it ...