Electronic Basics #33: Strain Gauge/Load Cell and how to use them to measure weight
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- Опубліковано 2 сер 2024
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You can get Strain Gauges, Load Cells and the HX711 IC here (affiliate links):
Aliexpress:
Strain Gauge: s.click.aliexpress.com/e/_d6Q...
Load Cell: s.click.aliexpress.com/e/_dTf...
HX711: s.click.aliexpress.com/e/_dXe...
Ebay:
Strain Gauge: rover.ebay.com/rover/1/711-532...
Load Cell: rover.ebay.com/rover/1/711-532...
HX711: rover.ebay.com/rover/1/711-532...
Amazon.de:
Strain Gauge: amzn.to/2BGbEIg
Load Cell: amzn.to/2npyuks
HX711: amzn.to/2khmhxh
In this episode of electronic basics we will have a closer look at strain gauges and load cells and find out how we can use them to measure weight. Along the way we will talk about the wheatstone bridge, suitable amplifier circuits and how we can use a µC to output the measured values of our weight measuring system.
Music:
2011 Lookalike by Bartlebeats
Killing Time, Kevin MacLeod
(incompetech.com) - Наука та технологія
I'm a certified scale calibration technician and you hit every point right on the nose. Your video is awesome and u do a fantastic job explaining everything so simply. Thank you for the info on integration.
It's incredible how my electronics courses introduce a topic, and you immediately produce a super informative video on it. Good stuff. Thanks a lot!
Fascinating. I've used strain gauges many times before in my work (mechanical design engineer) but never fully understood their operation....now I do. Thank you.
For me this was one of your best presentations. Who says you can't teach an old dog new tricks? Well done Scott, I'm ready to build a super sensitive scale.
Impeccable timing :D Just as I'm working on a project with load cells! Loving your stuff!
I know I've probably commented this before, but I absolutely love your handwriting. So clean and precise, just like your explanations.
Great GreatScott, great video as always. Have a great day! Salutes from ELECTRONOOBS
You are the coolest dood on the planet. ELECTRONOOBS.
Plz attach link for Arduino code ..for load cell weight measuring
Greatscott:"fullbridge"
Electroboom in my head:"FULL BRIDGE RECTIFIER"
fucking hell it's not even a joke anymore im suffering.
I really like your basics videos, this gives an essential introduction to the topic without getting into too many details. I think a good future topic would be filtering and signal processing, like basic analogic and digital filters. I think of only one suggestion for this video, in the part were you show the data stream and the difference between the weightless measurements and the weight of one IC, you could have used the Arduino Serial Plotter function to better display the difference, this is available in the later versions of the IDE, although it still needs some improvement.
Haaa!!! "Strain gauge" was the word I was looking for!!!!
I'm a french speaking guy and I only know "load cell" but this is now what I was looking for.
Thank you so much for sharing this beautifully made video.
Alex from Québec, Canada
I assume you speak not only English but your default language as well. That already makes you so much smarter than me. Then of course the knowledge you have gained in math and electronics, that you share with us, is a grand thing. THANK YOU!
Thanks for this great video. I think you saved me weeks of trial and error for a project I'm doing. Excellent channel!
When you are thinking about a new project with a load cell , and Great Scott upload an awesome video about it ;)
Great content as always, thanks for your work
Very cool! Thanks for sharing with us!
No problem
The moment when GreatScott uploads a new Video and you think ,,fck this shit, i watch the Video and after that i make my homework" xD
Yat
Or yay
Loves the way he explains....
Exacly same
Alucard Pawpad Yes... But i feel like, here in germany are 60% nazi-teachers that want to get back the old rules oft Scholl, where the teacher is allowed to punch the kids xD
This is exactly the video I needed. I have also purchased such a load cell and HX711 breakout board. Now I understand how it works.
I thought the load cell would use piezoelectric crystals instead of strain gauges, how wrong I was.
I couldn't weight to watch! There was very little strain in loading that info into my gray matter cells. I feel smarter already! Thank you.
Your videos have always been aspiring me to learn about new stuff which I have only learned about but never got hands-on experience. And I really wonder what kind of people are those who dislike your videos.
Your work is great and I learn a lot. :)
Thanks for the feedback. People will always find something to dislike, but that does not drag me down.
Omg im so excited about new electric longboard video!!
I really like your content try to keep up the good work im 14 and im in electronics more than 3 years, almost all stuff i know i learned from you thank you ;-)
excellent job explaining the differences between quarter, half, 3-quarter, and full bridge, and why they can help in various situations. Just what I needed!
Glad it was helpful!
I’ve been watching for years...just realized you are a Lefty. Your penmanship is amazing. My papers always end up snugged.
Thanks mate ;-)
For the adventurous: You can make an instrumentation amplifier out of normal low noise op-amps, then use oversampling + dither to get > 10-bit depth out of the ATmega SAR ADC. Feeding the whetstone bridge with a well regulated source, as well as making sure to air float (dead bug) your instrumentation amp is critical. (At these levels, merely the ambient moisture in the air condensing and re-evaporating on a PCB can cause variations in output. Professional systems use guard rings for this reason.)
Wow, what a wonderfully artistic and useful explanation!
Sir this was just awesome...just used the standard theories of standard wheatstone bridge,differential amplifier and a whole lots more and you converted to a real sensitive stuff!!!!! THIS WAS JUST AWESOME....I can now take different standard weights and can make a pretty decent weight machine using your theory you just showed!!! Thanks a lot Sir
You're welcome :-)
Again an amazing video ! I wish I had a colleague like you at work.
So I recently had to deal with a load cell in my project and having some troubles with it due to something I got wrong in this video I wanted to point out something: 1)at 6:29 you show using the green wire for A- and the white wire for A+ and that could work on some models but some times is the other way around, I've found people saying the opposite and some stating that sometimes the colors are not standard. 2) This is pretty simple but make sure to have some space under the side with the downward arrow with the weight marker, the measuring is done based on the fact that under stress the load cell bends a tiny amount that stretches the Strain Gauge changing the resistance (it's simple but it's something that shouldn't be left out in my opinion), mine had m4 screws and m5 screws and the m5 ones were the ones I had to use to secure it while the others were dedicated to the load; great video as always, I just wanted to share my limited experience to maybe help out a bit.
bro can you help me code?? I can't get the right codes for my project bro
@@lanceaeronreyes7579 so I used the Queuetue HX711 library by Scott Russel, it contains a Calibration sketch and an actual scale sketch it's all commented neatly and pretty easy to understand, the calibration did not work 100% for me and gave me a value even without load after calibrating, to fix that I just took that value and subtracted it from I (that in the sketch is the reading) I'm sorry if I'm late but I actually forgot about this comment, I hope it can help I avoided making a full explanation of the code because I feel like the example sketches of that library will be enough.
@@simoneazzoni3882 right on bro thanks for the help! I used the HX711 lib and tried something different. Then I tried to mix the knowledge I got from different videos and tutorials and gives me a 90% accuracy. I'll try your advice brother! Thanks for the help!
Another great video from +GreatScott!
Really great done! Fantastic explanation. Thank you!
Fantastic! My query got just answered in minutes! professional video and speech, thanks!
A lot of this I dont understand because Im just starting out with electrical stuff, but dang you really are a good teacher and are super smart! We all appreciate every upload you provide and the time it takes to edit each video!
Thanks for the feedback :-)
*Rider rolling down the road nicely*
*Rider goes over a bump causing temporary lift rider*
*Strain gauge erroneously senses rider no longer on longboard*
*System brakes longboard*
*Riders momentum causes him to faceplant*
Sounds like a timer would fit nicely between sensing the lack of weight and braking
That was my first thought as well! My idea was to gradually apply a little bit of brake resistance. If only the board was being slowed, it would happen quickly, whereas if the rider was on it, it would only slow down a little bit. But Rob's idea was even better.
Exactly what I thought!
"Sounds like suicide with extra steps" - cit. Rick Sanchez.
Inductive sensing for the rescue?
Thanks so much! I just got a broken Wii fit board with 4 load cells in the bottom. This video is really going to help me use them.
Very insightful. Thank you for this wonderful content.
OH THANK YOU! If you do more engineering esque instrumentation videos, you will gain an entire college of followers, I promise
you.
Amazing I fall in love with electronics.
Your videos are very educating and informing.
Last week I bought loadcells and the circuit to experiment - and this week you publish a video. Is this some mind reading you do? ;) As always, great video, thanks for producing it.
Robert Klauco how
VoltLog just published a video using the same 24-bit chip as well
It's just chance. Given that he has 1 million subscribers now, there is a high probability that at least one of them received a load cell on the same day he published the video even.
You really awesome , I learned a lot for your channel , keep the good work & good luck , looking forward for you future projects & lectures .
One way to overcome the noise is to sample the output of the HX711 over a period of time (say, 1 second) and average all of the samples. It's quick and dirty but would give you less noisy output and over several sample cycles the measured mass will be more accurate. (Probably why I always see digital scales change their output reading in time-discrete chunks, and it keeps changing for several sample cycles for a bit before settling.)
True, I think the Sparkfun library even includes such an average function.
Granted, such averaging is really only necessary if you're needing to measure tiiiiny changes in mass. For something like this where all you want to know is whether or not you've had to bail off your board, the immense change in output values far exceeds the noise.
i use Kalman filter for these purposes
i found implementation in youtube and copy-pasted its code :D
very precise and concentrated explanation . THANK YOU
I just learned about strain gauges the other day from my Electrical Trade Theory subject, so I understood the entire episode :D
Another great video. Thank you for sharing this.
I knew bout straing guages already, but this video was still hella informative and interesting.. thank you again for af great video From a fellow electronics dude, and cheers from Denmark :-)
Looking forward to seeing that new improved longboard :)
Good video GreatScott!😀
thank you over & over for you very helpful content
This is what ive been tryin to search for so long haha..
Bro i almost gave up at making a eboard you really motevated me and helped me thanks
Nice. We use strain gauges in car crash tests. To compensate for the temperature, we use another strain gauge on the metal base.
And the connection is then in a half bridge, as in the video.
Great vide, keep up the good work 👍🏻 I would love to see some more longboard improvement videos 😁 and some hub motors maybe? Cheers
awesome as always....i enjoy your videos everytime and my love for electronics keep on increasing thanks to u
Awesome
You are a amazing human,,,,great great job ,,,I got lots of knowledge from this video about weight measuring
Super Video! Hat mir sehr geholfen.
Fantastic description
Hello @greatscott, you can add the 4 strain gauges directly to the skateboard TRUCKS. it will measure the deflection of the metal.
This is what we did in my engineering instrumentation class this term!
very very good video. Sehr gute Arbeit!
Great video! That was the best explanation of the underlying principles of the HX711 compared to the other videos. I had a question... What would happen if I supply 3.3v instead of 5v? With reference to your video, it'd certainly have an effect on the step resolution (correct me if I'm wrong!) but would there be any others alongside?
When you see greatscott just upload a new video i was like oh sh*t gotta watch this before i sleeep
Love it !! Keep produceing more faster :-)
Btw is this you main job ? Or do you do sth else ?
Awesome video!
I took apart my kitchen scale and was utterly confused on how it works. Now i know thanks :-D
i needed that information!!! thx
I like your beautiful handwriting and information. Very Very good.
I would have thought of a more mechanical approach for the long board weight sensor application. But I was not aware this technology existed and I think it is an interesting way to do it.
Back to work Greatscott
Good work.. keep it up.. thanks for your time and efforts.. I had to use once this load cells a few year ago. HX711 works fine with arduino.. even for smaller weight changes.. but callibration was too Much messy..
Very nice explantion! 👍
always usefull information. Thank you very much
Why stop at using the strain gauge as a safety device only? Ditch the remote and use multiple gauges and calculate how your weight is distributed on the board. More forward, speed up, more to the back slow down.
That is actually excactly my groups Bachelor project for this spring (2019). Maybe that will be my first youtube video :)
Hi, I was wondering if there was a reason you picked the resistor value of 120 ohms for the wheatstone bridge, even though the strain gauge who used had a nominal resistance of 350 ohms?
Very helpful, thanks!
Great video .
Hello GreatScott! I am currently working on a longboard of my own and I would know how you attached the strain gauge on yours. Keep up the good work.
Thank you very much for the educational video.
Nicely done!
Amazing video! Thank you.
Will this sensor work in tension as configured? Or will it only measure compression?
It is the same in this case. Since it is a sheet of wire, one side is being compressed while the other side is being pulled (tension). The compression and tension has the same value, in finding the compression you will find the tension mathematically by calculating it.
thanx for providing this
good show
The moment you measured weight of this small uC was truly amazing, thanks for great video :)
Whoa! I think I followed all of that!!!! Thanks for the introduction. Do commercial home bathroom scales use this technology or do they use a different technique?
+northshorepx They all use strain gauges
Thank you!
I have donated u it wasn't much but thanks for ur help it helped me a lot in my hobby
Hi GreatScott, i was wondering if we can measure variation of voltage directly on the HX711 with a voltagemeter. thx for the vid
Something to consider when using strain gauges or load cells is their orientation. I worked on a project that used a load cell to measure load from a cable, but the orientation of the load cell would change the measurement. That's because of the effect of gravity on the cell, the housing, the cable... I had to incorporate an additional accelerometer and use that to offset the measurement depending on its orientation.
Hello Pete, can you please explain it in detail how you used an accelerometer to offset the weight measurements ? Thanks.
Nice explanation for newbies....
In my DIY longobard desing I´ve used a button on a remote control which you have to hold if you want to ride, if you release this button my longboard will start braking slightly. However this load cell is so fancy :D
Will you upload a video about the improved version of your electric longboard?
Wow, really nice!
Because of Greatscott .. I still think Electronics is easy
The longboard is back! Is the quadcopter next?
quadcopter project comes 2022
Fantastic video. How about a Io-Ion battery this time for the longboard?
Fine, I´ll wait...
GreatScott! so, before BER?
banano banana Well 2020 is The first Date... Its Like BER was finished 2013 xD
thanks for sharing. you made a good video.
excelente tus videos saludos desde Colombia.
Thanks for the great video, What is the maximum output voltage value at maximum load in a load cell (if the supply voltage is 5V)?
Awesome! Thanks bro!
good., you are really the great great great Scott! my biggest doubt was cleared thanks for making this video bro 😁
No problem :-)
Oh no i missed your video while makeing a 555 timer circui. P.s. it worked on the end😁😁.
im building a pair of diy speakers but im getting lost on how to choose the right components for my freaquency crossover. And i cant seem to find a desent guide on how. so please, can you do a electronics basics on that topic? Love your vids btw.
Great video, thanks! It‘s funny, I‘m currently using load cells for a project at work. I think, there is a key issue missing here: you need a reference voltage for both the microcontroller‘s ADC and the load cell‘s positive excitation (+5 V in this case). Otherwise, small voltage variations in your power supply voltage will mess up your measurements. Especially 24 Bits of resolution are no use without a stable reference voltage. Also, your adjustment trimmers also tend to drift with the power supply voltage, and depending on your circuit will even increase the offset regarding the microcontroller‘s interiour reference voltage. That is the exact mistake I made earlier with my own project. I dont‘t know, if the breakout board module inherits a stable reference voltage, but if not, then your 24 bits resolution mean nothing to the actual measurement.
EDIT: just looked at the datasheet, the HX711 has an internal bandgap voltage reference, so no problem there. But for the pure analog differential amplifier solution, a precision reference voltage feeding both into the ADC and the load cell is still necessary. And the differential amplifier needs a bit higher supply voltage in order to avoid saturation at full scale output voltage.
Metalhead777 Thats why you have to calibrate it in arduino, reading values and averaging
Jo el Caamaleón That‘s right. But still, I prefer using a precise reference over calibrating and adjusting the system each time. Voltage drift not only appears during warm-up time, but also generally over the life-time of the system, with temperature and moisture changes, mechanical stress and so on. In a finished product you can‘t have a user calibrating it all the time. And especially in the proposed use with an electric skateboard, which goes through tremendous temperature changes and mechanical stress (vibration!), this is not a practical approach. For testing it‘s fine, but any longer use needs reproducibility without the need of repetitive calibration and adjustments.
Im a kid. I learned this better than math at school.
Edit: Please do a DIY Or Buy for Function Generators
Brilliant
@@greatscottlab I'm an idiot adult, but a long time viewer/subscriber, what's a Function Generator?
I was wondering how those things worked when fixing a scale, now I know!