Potentiometer Values? Does it matter in your next Arduino Project?
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- čas přidán 23. 07. 2024
- Want to use some Potentiometers in your next Arduino Projects? What value should you use, 10k, 50k? Well let's see if it makes a difference!
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Been researching this for a few hours, and this video really rounds it all up for me. Wish i'd found it sooner! Thanks so much for posting
Be good to also explain that a pot is not just a variable resistor, but a complete voltage divider.. as resistance increases on one side of the signal wire connection point it decreases an equal amount on the other side. The total resistance seen on the overall connection from 5V supply to GND is the value of the pot. This also determines the current induced in that connection (as someone mentioned below - if value of pot is too low, could induce large current & damage supply.. unlikely though as most pots have large enough resistance value).
Cheers
The most helpful video I found...thanks...it cleared my doubts
When you buy a pot and intent to use it to measure linear displacement - are you given the correlation between voltage and distance? Great video BTW
Great video and explanations! I am really new to building electronic circuits. In my project, the parts list has 10K pot but a 50K was sent. I built it anyways figuring the value shouldn't matter much. The project is a very simple LM386 OP amp. I watched your video to the end and at 6:54 you mentioned this does matter for the pot values in these applications. Is this why my should be ridiculously easy project does not work?
Thanks for the info!
Thank you. Great demo. Clear :)
Nice, how work on 36v ?
Just remember that there is difference between linear and logaritmic Pots (Lin / Log)
I have my cars throttle body pot. I connect it on my arduino and im reading values from 512-920 instead of 0-1023 . I guess its my pot's resistance from it's own that give that value. Is anything i could do to make it work to the full range or should i modify my code to split that range of existing pot to 255 values of output?
If we are talking about an actual driveable car and not a remote controlled smaller one: pretty sure it's something digital and it get's corrected later on, or might use some error correcting in combination with the ECU in order for it to know about the sensor being present and in working order, since drive by wire is very common for years already.
It could also be calibration meant to be used so that the gas pedal registers a range from standard idle RPM to something considered more safe by the manufacturer instead of full acceleration...
That was helpful, thanks👍
How many 10k pot can I connect with Arduino Mega along with 16channel multiplexer?
that means 16x16 pots = 256. but will it function normally if powered with USB?
my concern is if there will be any effect on the reading as i am planning to make a midi controller with almost 200 knobs.?
Probably not a problem, you will probably need a separate power supply so the multiplexer itself is stable enough, especially since you are going to be using multiple ones you will probably exceed the capabilities of the Arduino's power producing capabilities.
I hope your project worked out by this time though :).
@@Dutch3DMaster thanks for the reply. yes i completed the project. the video is on my page now
Helpful video!
There would be one reason for using a larger Potentiometer and that would be in a battery application with a number of potentiometers the current draw would be lower and then the batteries would last longer.
+Ken Heinrich hi , but the Atemaga chip is able to sink or draw a 20mA max what ever the pot value ; larger than 20mA the voltage divider is useless .
+Akrout Osama that is per pin, but the whole package can provide 200 ma through vcc, analog reading are sensing on a point. Vcc and gnd of a pot are where the power flows through
+Akrout Osama This is about battery life. The lower the total current the longer the battery last.
how can you make the potentiomater only rotate lets say 15 degrees or 20 degrees? how can you adjust the rotation of pot to go from zero to 5 volts or off to full on and only turn the pot so many degrees?
Physically this is not possible for most (and if you do find one that has such a rotational range of movement it's probably expensive) but you can do this in the Arduino code with mapping the value to something new.
Keep in mind that this will cause trouble when you exceed the maximum value electronically: you will basically restart the electronic reach of whatever it is that you do with the input's data (As in: if you state that 0-128 is 0-255, after 128 on the input this will cause problems because it will not have a clue what to do with that value).
If you do want to solve this physically you could try to find a button (A Ritel or some different brand) with a notch on it that hits a part on the case your project is housed in so it stops movement.
Im using 10k pot with arduino for running stepper motor but the stepper dosent run at full speed it can do! The code has no speed max or anything defined. Help
1023 might not be 5V, but somewhere along 4.6V. I'm not sure if this will matter for the output stage of the Arduino, but it could do that.
If the stepper motor is run through PWM, it might be that the frequency for the PWM output is not high enough, and the motor tries to keep up with the low frequencies but has to much inertia to not act upon it quickly enough.
I'm having problem with volume pots. Never smooth transition through travel. What?
What you did not discuss is, although the position of pot is static but, its value is changing and it is a very big issue because if you build a program which send incremental or decremental code when pot val increases or decreases respectively but if pot value continuously swing back and forth then your program will continuously send data which is disaster, how will you solve it?
Make a report and average out the values over a lastmillisecond type of delay (to not stall other operations) loop, so that a value needs to change more than 1-2 back and forth.
thanks ! very useful
Hello, I'm a complete newbie. I want to build such a circuit with 3 pots for a DIY sim racing pedal set. Can someone help me get the schematics for this circuit? (how to connect the wires without breadboard?)
Supersimple: Just solder the wires as you see them on most breadboard setups to the potentiometers directly, and use either pin headers or cut up a Dupont style wire that you might have bought with your Arduino and use that as the connector on the Arduino side of things.
If there's anything surrounding Arduino's this is about as simple as you can get it.
The Tutorial page for this tutorial is now available on our website here: brainy-bits.com/tutorials/potentiometer-values/
Thanks for watching!
i'm working on joysticks recently and the analogRead is really a pain in ass.
the read value is always not so accurate that you just can't easily map the value.
analog goes between 0-1023 in arduino, but the middle value is never 511 or even close to this value.
Zelra 仙賢戀軒 this is kind of a late reply but, you might be using a "logarithmic" potentiometer and not a linear one.
Most joystick scripts I've seen do some averaging on the input, almost as a hysteris kind of thing so it stops the input from bouncing between 1-2 numbers up and down.
The logarhitmic versus linear thing could be something as well...
Good tutorial on a topic that perhaps should be obvious, but was not to me.
+Garth Howe Thanks Garth, was always wondering this myself :) Thanks for your comment and watching!
gr8 vid.. thanx
why you're connection at arduino pot is different mine at left pin is ground and at the right is 5 v
as you (arduino) measures the middle pin. The middle pin is 0 - 5V by its position. No matter the potentiometer value. How the video shows.
can 10k potensiometer can be replaced 50k potentiometer.
Whats the difference between (a)20k and (b)20k.
Could you make a tutorial on how to wirelessly control a stepper motor?
+Californian Bill Check out our other videos like this one were I used an RC remote to control our cameras: czcams.com/video/yHhU_TY2kcs/video.html
You could use some of that code with some of our others that use Steppers and control it that way. But if you have something specific you would like to do, let me know :) Thanks for watching btw!
+Brainy-Bits Cool thanks!
+Brainy-Bits Cool thanks!
+Californian Bill You're welcome :)
Pot value does make a difference in the lower value and for less noise. If you connected a 20ohm put. power supply would blow. I know you were genralising here, but someone will try it and complain.
+Terry Peake Thanks for the comment. I don't understand what you meant by: power supply would blow? can you explain what you mean?
+Brainy-Bits As the pot is a resistor. one side goes to plus 5 and the other to ground, having a very low resistance pot would draw a lot of current from the supply causing it to overload. I was just pointing out incase someone had a very low resistance pot.
+Terry Peake I guess it would act like connecting an LED without some sort of resistor. Thanks for pointing that out... I don't have any pot lower than 5K but in case someone has on hand a very low value pot it's good to know to not use one that is super low value.
It is simply Ohm's Law: U = R · I, where U is the voltage, R is the resistance, I is the current. Since you always have 5V, the resistance determines the current flow. There is nothing uncommon about a 50ohm potentiometer, and the result is:
I = 5V / 50ohm = 0.1A
That means that you have 500mW through the potentiometer, and whether or not the voltage regulator on the Arduino will burn depends which one it is. Most regular small potentiometers cannot handle that power, though, so something WILL burn :)
On the other end, when you use the very large values, such as your 500 kilo-ohm, you have a fairly low current flowing (here 10uA), and that makes your readings more vulnerable to disturbances from other sources, such as noise from power supplies and things like that. Of course, if you have a battery driven application, you will want to limit the current as much as you can, if it is supposed to be active all the time. Then you need to compromise.
So the short version of this comment: It DOES matter which potentiometer you pick. Very much so, even.
@Mikael Klynder So what would be the best you would generally recommend? 100K, 250K? Just for analogRead purposes. Thanks!
Also should've touched onto the subject of Logarhythmic and linear pots ;)
+Glychee S Will keep that in mind for another video :) Thanks for the suggestion and for watching!
+Brainy-Bits also why, when and where to add current limiting resistors and how that affects the reading
Nice and simple... ;)
+Mide Sabic Keep in mind that this is a simplified view about using Potentiometers with an Arduino, but like others have said (Check comments) there's more to it than what I show here. But for most applications it will do :) Thanks for watching!
awesome
Perfection
I was thinking lon long time to figure out why the biggest value is the best. Now I know so beleive me use at least 100K if possible!
Please use 10K or 20K: arduino.stackexchange.com/questions/51230/what-is-the-lowest-resistance-pot-that-is-useful-with-an-analog-input
Those has different RESISTANCE value...4 ways audio1) negative output input ...volume 2) pin1 pin2 or pin 2 pin3..pin1 pin3 circuit with CAPACITORS L1 pin2 negative..4) pin1 pin3 out pin2 CENTER tap ...all pots has different values adjustable VOLUME CURRENT IMPEDANCE FREQUENCY ...THOSE ARE THE FOUR WAYS CIRCUIT...4POTENTIAL BALANCE HIGH LOW FADE FRONT BACK EQUALIZER FREQUENCY VOLUMES GAIN LOUDER EXTRA BASS....
what
how about higher voltages????????? thats why i was here
It depends on what you call higher, if anything, it's rare for things higher than 24V's to be controlled with a pot directly....because the amount of heat dissipated (it's a resistor after all, just a variable one) will become a problem quickly....
Should you want to switch higher voltages, look into higher power transistors or even MOSFET's and control the input through that. I will warn you that MOSFET's can be more difficult to control.
Thank you .. thank you ... thank you..... It is soooo frustrating to have something you really want to make, and spend a year trying to make it happen. I've wasted hundreds of hours on this stuff & it is nearly impossible to find good source material that you can DO SOMETHING WITH!!! I would like to see all Arduino forums taken down and educational postings put up in their place. Complete waste of time!!!!!!!!!!!!!!!!!!
D'Ho!