How to use Force Sensing Resistors
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- čas přidán 7. 09. 2024
- This video describes the operation of Force Sensing Resistors and how to interface them to microcontrollers using an ADC channel.
A LED pressure display and a toggle switch circuit is covered.
Very cool. You get some interesting stuff. Haven't heard anything about Forth in the last 25 years, but it looks useful here. We always joked that it was a "write-only" language. But one reason I think it was so useful is it forces the programmer to build his system from the bottom up and test each part as (s)he goes.
Yes ... very true. You are debugging as you build each part. It is the best language for controlling hardware. Have been using it for years.
your explanation easy to understand ,thanks for the video
You are welcome! Thanks for the feedback.
Check out an updated video: czcams.com/video/2XiRnoc8ZRo/video.html
1st time seeing anyone using forth btw good info about fsr
Interesting, hope the price goes down a bit on those.
Really enjoying your channel, interesting stuff.
I also noticed the high prices ... When they first came out they were quite reasonable.
Dude it's super easy to make. You can make them with graphite pen, paper and curved plastic that will bulge above contacts when it's not pressed.
does it only work with fingers or other materials, too?
Anything that can generate pressure onto the sensor.
Thank you...Very useful.
You are welcome
Discovered this video while searching for FSR resistors. Never knew you could code arduinos using Forth. Took me right back to the 80's. what IDE do you use?
The compiler and interpreter runs on the microcontroller so there is no IDE, you just need a simple serial terminal program like Putty or TeraTerm. All my videos that involve coding use Flashforth. czcams.com/video/2XiRnoc8ZRo/video.html
why do we have to use voltage divider, how do we select the upper resistor for voltage divider circuit?
Hi , great video.
Im thinking of using a pressure sensor for a project. I need to detect a person doing a sit up. So at the bottom or the rep I was thinking of using a pressure sensor to make sure they are doing the full range of motion. Would these pressure sensors work for a person do you think?
I want to use this fsr to check the clamping force when I hold my phone so I can use this value as a reference for a phone clamp with an m6 bolt that is used for clamping
Fair I could use Springs but I assume the bolt will be more adjustable and with an fsr
Thank you.
You're welcome.
@@0033mer Cool, that's very nice.
I'm looking to possibly use this kind of sensor on top of a Roland sample pad to be able to queue another device when the pad is hit with a drumstick. Do you think these sensors would withstand drumstick hits? Not too hard, and only at the beginning of songs.
I don't think a general impact sensor would work since it could likely shake around quite a bit. Having the on-hit control in an area like this would work pretty well if it won't break right away haha.
The small surface area of the drumstick tip would probably "dent" the plastic membrane of the FSR. You could try using a Piezo vandal proof switch or an encapsulated Piezo speaker. Check out this video:
czcams.com/video/mmfEc5qeFMI/video.html Another route would be to use static foam as a pressure sensor. czcams.com/video/wEqfHo_guG8/video.html
@@0033mer Thank you for the response, and good points and suggestions. I decided on trying out the FSR and have everything on light-tap settings. So far so good, but I'm interested in some other options as well.
Cheers!
Do you think these sensors are sensitive enough to use for an air pressure chamber? So to measure low values of air pressure
Success will depend on what you use to interface the pressure gradient to the FSR surface. Check out this video for more ideas. czcams.com/video/2XiRnoc8ZRo/video.html
I've given 1000th 👍
Can I set it so that it only activated when I press lightly on it? It shouldn't activate when pressed hard.
Other than that, very useful video!
I have a question.
Do these types of sensors serve to detect the pressure that a person makes when stepping on it without damaging it?
Yes ... as long a the sensor is not bent, creased or torn by the object applying the pressure.
I'm using the FSR, and so far it didn't break or anything (I use 5 of them), but you need to be careful not to press too hard on one spot, this could damage the FSR (if you want, you can find on eBay FSRs which are capable of dealing with 20, 50 and even 100 Kg).
nice! helped me a lot! ty!
Glad it helped! Here is an updated video: czcams.com/video/2XiRnoc8ZRo/video.html
Hey, I really liked the video though I have a question however.
I looked up on the internet to find these, and the weight ratings ratings were at 0.5kg minimum. Are there any FSR-s with a lower threshold? If so, where can I buy them?
Look into using a sensitive load cell.
czcams.com/video/vvIe0BFBlFI/video.html
The FSR's I am using have a threshold of .5 Newtons or .05 kg
@@0033mer Thank you very very much Sir :D
Hello, do you maybe have tis code also in arduine IDE. I would like to use it for my school project.
Hi! I am using a car seat occupancy sensor in a project. I am trying to connect the sensor to the Arduino Uno microcontroller. I am having some trouble with the wiring. The sensor has two pins. I am assuming one is for power, and the other one is for the analog signal. I connected a 10k resistor to ground and one of the sensor pins together. I then took a wire and connected it to an analog pin. When I get my reading, it shows a voltage of 0 even when I apply a load. Do you know what kind of resistor would work for this case? I have tried a few different resistances (higher and lower), and it still doesn’t work. I appreciate your help.
Put an Ohmmeter across the sensor and measure the resistance at rest and triggered, there should be a change.
With the sensor in series with the resistor, apply 5 volts and use a voltmeter to measure output at rest and triggered
If you get a voltage change with the meter and not in your code, check your code.
Hello, I have a question: Is it possible to connect couple fsr sensors in series to increase the load force? I want to create a surface for 60 up to 80 kg mass. Looking for your answer.
The FSR will saturate after the max pressure is reached and the output will not change with further pressure.
The best way to go would be to build a mechanical force reduction system using a beam and adjust the fulcrum position to meet your needs.
0033mer but is is possible to use about 10 fsr sensors, connect them to arduino And summed them in the program?
Has anyone ever tested paper-based force sensors from Papier Logik? U can redesign their shape and size which seems great.
I found sensors online that have a range of 150Kilograms and i want to create a pad that measures force of over 1000Kilos. Can combining several sensors help you increase the range?
Ik this is a bit late of a reply, but if you found a way to evenly distribute the weight over multiple sensors, then add the readings of all the sensors, you might be able to do something like that.
Hi. Have a gooday
I have a trouble with force sensor FSR UX 400 series. I want to didplay the force(N) on Led 16x2, but I can not write arduino code. Could you help me write down the code connect Force sensor to arduino board,please?
I love your video, I was also just wondering if i were to connect a force sensitive resister to a single LED light using just a couple wires would that work? if not what else would I need? The reason I ask is because i had an idea for a cosplay and it would need at least 1 LED on each wrist nothing to fancy
Driving a LED directly with a FSR would exceed the max current of the device. You could feed the output of a voltage divider ( a per video schematic ) into a CD4093 wired as an inverter driving a LED.
@@0033mer what if I were to use a battery holder instead? For a bit of clarification the idea I had in mind is for a spiderman cosplay and it's a small device for my wrist that looks like a web shooter and whenever I do the web shoot gesture the LED would light up. As you can probably tell I'm not very educated on this sort of topic
The simplest solution would be to use a battery and a micro pushbutton switch. Check online for micro switches.
We like to get an Led touch panel made for our company , this LED panel will glow as when the object hits the panel .
So, I’m actually thinking to use it as a device to measure force applied in physiotherapy can I use it that way? In the sense if a guy with broken leg is using a walking stick can I measure the force applied
I'm doing a similar thing (measure the ground reaction forces while walking and running).
It is possible, but not accurate because:
1) When you walk, you don't press on a few millimeters diameter place, you're distributing the force all over your leg, so in order to truly detect how strong the person pressed, you need to use a lot of FSR (and it's not very practical).
2) There is a chance that while walking, the patient will press really hard on one spot that the FSR detects, and if this force is really big it could damage it.
So, you can use it (like I do), just be aware that it's not perfect :)
Aviel Eliyahu u can use one huge FSR which is foot shaped! Which was expensive,so I ended using a normal one! Didn’t work so effectively
@@akhilthiru
Where did you find a foot-shaped one?
The normal FSR isn't good enough for your purpose?
Aviel Eliyahu hope this will be of some help!
www.semanticscholar.org/paper/Application-of-Force-Sensing-Resistor-%28FSR%29-in-of-Rana/bbd3310ad80535c164d2514d909c15ad46cab028
Nah! Dude it wasn’t giving out accurate results and on top of that it was reaching its saturation when applied a little force.
@@akhilthiru
Thanks!
For some reason I can't download it, do you think you can send me a copy via Email?
Thanks for the demo! I'm considereing these for a weird use-case and would love to hear your opinion. My goal is to create an impact detector for thrown objects. My plan is to sandwich one of these between two cushions, then when it is hit with a projectile, I will see a sudden spike in voltage. My concern is whether you think repeated abuse in this fashion will gradually deform them and saturate their readings, resulting in an eventual constant trigger on-state.
Sadly vibration sensors won't work for me use-case as this will be in a pretty noisy environment so I wanted to check these out. Any insight would be greatly appreciated :)
Yes, you could make this work with a pipe, and a ball bearing together with an FSR. Other sensors can be made with Piezo, anti-static foam and Velostat. The best way would be to use an accelerometer. Check out these videos for more ideas: czcams.com/video/2XiRnoc8ZRo/video.html czcams.com/video/nDmlsHCuBlI/video.html
@@0033mer Wow, this is by far the most helpful response I've ever received on CZcams! :D
I find the antistatic foam concept very interesting, I may give that a go. Thank you so much for your help!
You're welcome!
What is the nominal resistance of type 402? Which is written |||IFSR_||||18
Sir, are there smaller size force sensing elements ??
Yes, smaller elements are available. czcams.com/video/2XiRnoc8ZRo/video.html
Hey, nice video!
Do you think I could use this sensor to mesure the force of a hammer impact?
Yes ... that would work. You would have to provide some sort of protection to prevent damage to the FSR.
Another solution would be to use an accelerometer.
Check out this video: czcams.com/video/nDmlsHCuBlI/video.html
It was already in my fav list ;) But I saw that you used accelerometer to mesure the deplacement of the surface. In my case, I will use it but also a sensor to mesure the force and the time of contact between the hammer and the surface (basically, I gotta do an impact hammer). If you have more advices, give them to me :D
Check out this application note:
akizukidenshi.com/download/ds/interlinkelec/94-00007-measuring_pressure_from_strip_sensors_application_notes.pdf
Can i use this to measure pulling force of a wire?
I am looking to use these sensors for the purpose of testing for the specific impulse of sugar rockets. This means that I will need to translate the ADC value into a force in SI units, ideally in Newtons. How would you suggest I approach that process?
The FDR's are not very linear and would saturate very quickly. Your best bet would be to attach your engine to a cantilever beam and measure the deflection or use a beam together with a strain gauge maybe from a digital bathroom scale.
Great video! thankyou. I'm very new to Arduino and wondering if you have a wiring diagram you could share. I know you went over where you plugged things in on the video but, again, I'm very new and not sure the exact method. Thanks!
For a simple hook up put a resistor in series with the FSR. ( 3:08 in the video)
Use a voltmeter to monitor the output voltage which will change when pressure is applied to the FSR.
@@0033mer thanks, I'll give it a shot
Hi, I want to make the static characterization for the fsr402. Do you have any ideas on how I can measure the force applied to the sensor to build the calibration curve?
You can put the FSR402 on a smal sensitive weigh scale and chart pressure applied vs output resistance. You could also build your own with a load cell: czcams.com/video/vvIe0BFBlFI/video.html
sir can u give me some idea for how to caliberate the total weight of the body if we put this force flex sensor in the sole of shoes , or which sensor can give more pressure capacity than this as it having 100 to 10kg , and can easily fit in sole of shoes
Check out this video: czcams.com/video/2XiRnoc8ZRo/video.html
Question: Could you put 1 of these in a shoe and detect pressure of your feet accurately? Are there any inverted versions?
You could make that work. A sensor on the front of the foot and one on the heel would enable you to monitor the weight transfer during walking. You would have to come up with your own calibration scheme.
Can these force sensors works in fluid?
very nice
thank you
Hello, I really enjoyed watching your video! I have a few questions though: How much weight/force (in Kg) can the FSR detect? Also, can I program an FSR to only react to a very specific amount of pressured over a sudden period of time? If not- are there any alternative types of FSR-like sensors that can do so, while still being as versatile (physically) as these FSRs you've displayed?
Force detection is in the range of 20g to 20kg depending on your actuating mechanics. (surface area, size of FSR ... etc)
Rise time detection is fairly fast, around 3 microseconds.
Here is an App note for more specs: interlinkelectronics.com/integration_guides/FSR400Series_IG.zip
Awesome, thanks so much for your quick response! I subbed.
What is the best way to connect the input and output lines to wire?
Soldering is bad because of the FSRs sensitivity. I have those screw clamping dc connectors but the FSR terminals are too short and close together to fit. Conductive glue seems like an unreliable way to connect.
The FSRs I used in the video have solder tabs. If you solder quickly and don't dwell too long on the tab it can be done successfully.
If you have the bare tail type, they are made for flat flex connectors (FPC)
www.digikey.ca/product-detail/en/amphenol-fci/66226-002LF/609-2176-ND/1002491
Last option is order them with male/female headers installed.
0033mer Thanks, I've been looking everywhere. Thats exactly what I needed 👍
What steps would you have to take to make this work on a 12v circuit?
A reply would be appreciated, Thanks
If you just have a 12v power supply, convert it to 5 volts using a LM7805 voltage regulator. If you want to run the FSR on 12 volts use a 82k resistor in place of the 47k. The circuit is basically 4 LEDS driven by the Nano GPIO and the FSR voltage divider fed into an ADC channel on the Nano. The circuit is similar to my voice switch video:
czcams.com/video/cGoptAdJa5w/video.html
0033mer Thank you for your reply
Hi, great video!! Is there any way to do almost exactly what you did without an arduino? Thanks a lot
Also, is it possible to calibrate the sensor to give the LEDs light for a given weight applied?
Yes .. you can use a LM3914. Check out the data sheet.
The FSR is not linear so you would have to do your own calibration
hello, did it work whit the arduino? @@juanfelipegarzon8281
Hello , can I know the model number for the FSR
www.adafruit.com/product/166
thanks
You're welcome!
Does it only work with a human finger, or also with something covered, such as asheet of plexiglass?
"Anything" that can apply direct pressure to the sensor will activate it.
0033mer thanks for the info and the quick reply! :)
@@0033mer can it detect small force? such as force feedback of a controller?
Does it works in fluid???
what to code in "toggle" part? If pressure applied then turn on , and again applied then turn off , how to write this in arduino?
you can use bitwise operation exclusive OR (XOR) to compare the [current condition] to the [true condition]. example if [0] ^ [1] = [1], if [1] ^ [1] = [0], it will toggle.
Im trying to do a similar thinh using a raspberry pi . Is there a way to do it ?
The Raspberry Pi does not have an onboard ADC so you have to use an external ADC board.
Check out this link from Adafruit. learn.adafruit.com/raspberry-pi-analog-to-digital-converters/ads1015-slash-ads1115
Read the analog values from the FSR voltage divider using the I2C bus on the Rpi.
Hey, thank you so much....
Your video is very informative and awesome.
But i wanted to know whether this sensor can sense the force of a human body's back.(i.e while sitting on a chair).
Thank you and waiting for the reply.
A FSR sensor by itself on the back of a chair would not be very reliable to sense a body's back in a sitting position.
The surface pick up area of the sensor is too small to pick up the pressure exerted by the same area of someone's back.
Also different size people would contact the back in different areas.
If you made a back plate that concentrates the force to a point on the sensor, that would probably work.
You could also look into Piezo coax cable, proximity sensors or even a flexible air bladder and detect air pressure increase.
what the software u used for the leds?
The program was written in Forth. flashforth.com/
Hi, I've built the circuit using the Arduino but i'm losing power along the LEDs. Is there any way to combat this?
A reply would be appreciated. Thanks
Check your wiring. Power the LEDs separately, one at a time with test code. You can also build a pressure to frequency circuit without LEDs. czcams.com/video/ZUkWkcGAJIE/video.html
@@0033mer I've done the circuit and it works fine with the code but i'm still losing power. Even when there's only 1 bulb in the circuit it is still dim. Is there anything you could suggest?
I need to see the schematic of your setup.
@@0033mer I've messaged you the set up on email. Thanks for your time and effort.
Your layout looks ok. Make sure your GPIO pins feeding the LEDS are configured as outputs. If not the LEDS will be powered through the internal pull-ups causing the LEDS to be dim.
how do you select your resistor values
If you look at the data sheet (Fig3) you will find a Vout vs pressure chart for different resistor values in the voltage divider.
Here is the link: www.trossenrobotics.com/productdocs/2010-10-26-DataSheet-FSR402-Layout2.pdf
Can I use this underwater to measure water pressure?
The FSR would have to be housed in a watertight enclosure with a flexible membrane/diaphragm on one end.
As the pressure increases the diaphragm would press against the FSR giving you a depth reading.
You would have to come up with your own calibration scheme.
Honeywell makes pressure sensors that can be used underwater which might be an easier solution.
0033mer - That makes sense. Thanks
Could these actuate servos ?
Yes .. you would have to convert the FSR output voltage to a PWM signal compatible with a servo motor.
What units does the sensor read off in?
The sensor is not linear so you have to calibrate the voltage output to your desired units of either grams or Newtons.
www.trossenrobotics.com/productdocs/2010-10-26-datasheet-fsr402-layout2.pdf
@@0033mer Alright, So follow that chart provided with a voltage divider? and choose the correct line to follow depending on which resistor I've implemented into the circuit? Correct? (lastly, do you know if this FSR will read off the force felt by a force of wind?)
To measure wind force you would have to build an interface with a wing of known surface area connected to a lever and fulcrum setup to magnify the force which can be detected by the FSR.
can it is used to measure the flow rate
The FSR is not a linear device.
I m just asking that if we used it in directly in flow of liquid if water flow strike on the fsr is it give flow rate
If you would concentrate the flow of water onto the FSR it would react and change resistance.
You would have to come up with your own calibration equation to get a flow rate output value.
is it capable of measuring force applied if we use it in medical catheters ????
Can I get a copy of your Arduino code for this please ?
Everything is fine but the connections are not shown clearly
schematic at 3:10, common rakesh
Hi can i be in punch machine
how can i increase the wight to 80 KG ?
Omfg😲😲😲
force sensing resistors library file for proteus please!!