Hello Cody,

unfortunately I can't find the capsense.h library anymore.
do you know where I can find it?

greeting peter

https://github.com/PaulStof...

Looks like the library has renamed from CapSense to CapacitiveSensor as well, so you may need to make a few code adjustments.

Hello Cody,

thank you very much. I have adapted the code. I don't know if it's so neatly programmed. But it works.
The unpleasant thing about it is that the motor fader runs very jerkily. Similarly bad as the former Yamaha O2R ;-)

I don't know if it's the fader. I use this one:

ALPS RSAON11M9 Motor-Fader 10 kΩ 0.5 W linear

But I suspect it's the sketch. I don't know if it can be improved from a programming point of view. Or maybe someone has an idea how you can dampen the start and stop phases with electronics?

The proper way to fix it would be to implement a PID controller loop to reduce the motor's speed as it approaches where it should stop.

As a "quick fix" you could reduce the voltage on VCC1, or you could change the 10 in void updateFader(int position) to a larger number like 15 or 20. This padding gives the fader a little more room to overshoot without needing to correct itself.

I also remember having to mess with the sensitivity on the capsense module based on the type of fader and the fader cap (if any) being used. I can't give you any good guidance there, because it's been a while since I did the project.

Final thing to check - make sure your grounds are clean. I had trouble with odd behavior when running the Arduino off of my computer's USB port.

Curious what it takes to scale this up to 8 faders... or 20 faders!?

A good power supply for all of the motors, an encoder to read from multiple faders, and some sort of PWM driver to drive multiple H-bridges from a limited number of pins would work.

Hello Cody,
I've recently purchased a fader from ALPS: RS60N11M9A0E
I read the code that you wrote and they make perfect sense.
I'm however, struggling to connect the fader.
"To read the position, connect the bottom of the fader to ground, the top of the fader to +5 V from the Arduino, and connect the wiper to an Analog In pin. “
I really have no idea what you been by the "bottom" and the "top"
according to the seller I bought from pin 1,2,3,T each stands for ground, input, output, and Touch sensitivity.
I've also attached the document from ALPS. Could you explain the pin based on your code?
Thank you so much in advance.

https://uploads.disquscdn.c...

Hi,

Based on your description, I think it would be like this:
- Ground -> Ground
- Input -> +5V (VCC1)
- Output -> Arduino Analog Input 0
- Touch -> Arduino Digital Input 7 and then R2 (1MΩ) would connect D7 and D8

You can always use a multimeter to test, too. Set your meter to measure resistance, place the fader towards the bottom (about 25% of the way from the bottom), and test the pins. Ground to VCC1 (+5V) should measure 10k since your fader is a 10k fader, ground to A0 (Output) should be about 2.5k (or less than 5k), and VCC1 to A0 (Arduino Analog Input) should be about 7.5k (or more than 5k).

Thank you so much!!!!! It worked flawlessly. I just have one more question that do I have to use metal caps for touch sensitivity? I imagine if I use plastic ones arduino wouldn't be able to read the capacitance due to insulation of plastic? Thx again

I believe there are some plastic caps that have a layer of aluminum below the plastic, but I can't remember where I saw them. Metal would definitely be easiest and likely would feel a little higher quality.

Thank you so much! Unfortunately I think I've purchased log(Audio) pots instead of linear ones... With Arduino 's 10 bit I'm not getting accurate analog readings...I'm thinking about reading resistance and maybe multi-map them to somehow mimic a linear one? Do you have any other ideas that I might be able to make the pot as close as possible to a linear one? Please let me know. Thank you...
PS where do you get the linear slider pots with motors? Can't seem to get them from where I'm living...

Hi Cody,
I have got a slide potentiometer which doesnot have the touch sense in it.
https://www.mouser.in/datas...

I have connected the circuit as per your instruction. I am able to calibrate where the code does get the value for max and min value of fader.

After that the moment I turn the pot...the code gets stuck..the values in Serial monitor doesnot move at all.

My code is as follows


const int motorDown = 5; //Declaring where our module is wired
const int motorUp = 6;
const int wiper = 0; //Position of fader relative to GND (Analog 0)
const int pot = 3;
double faderMax = 0; //Value read by fader's maximum position (0-1023)
double faderMin = 0; //Value read by fader's minimum position (0-1023)

void setup() {
Serial.begin(57600);
pinMode(5, OUTPUT);
pinMode(6, OUTPUT);
calibrateFader();

}

void loop(){
move_fader();

}

void move_fader(){
int pot_state = analogRead(pot);
int wiper_state = analogRead(wiper);
Serial.println(pot_state);
Serial.println(wiper_state);

if (pot_state < wiper_state - 10 && pot_state > faderMin) {
digitalWrite(motorUp, HIGH); //Switch between this HIGH and LOW to change direction
while (pot_state < wiper_state - 10) {}; //Loops until motor is done moving
digitalWrite(motorUp, LOW);
}
else if (pot_state > wiper_state + 10 && pot_state < faderMax) {
digitalWrite(motorDown, HIGH); //Switch between this HIGH and LOW to change direction
while (pot_state > wiper_state - 10) {}; //Loops until motor is done moving
digitalWrite(motorUp, LOW);
}
}

void calibrateFader() {
digitalWrite(motorUp, HIGH);
delay(500);
digitalWrite(motorUp, LOW);
faderMax = analogRead(wiper);

digitalWrite(motorDown, HIGH);
delay(500);
digitalWrite(motorDown, LOW);
faderMin = analogRead(wiper);
}


Try commenting out everything below the `Serial.println` in `move_fader()`. Make sure the values are printing correctly and that moving the fader up actually moves the values up. It's possible that you have the wires reversed.

Keep in mind that without the touch line, you cannot change the value with the fader - you can only change it with something external (like the potentiometer you're using).

hello Cody.
Im looking for the nominal tention of the capacitor? voltage of motor?
Thanks and keep u the good work!

Hi Sebastian, I'm not sure what you mean by the nominal tension of the capacitor? The values for the components are listed on the schematic and in the blog posts. Here is the spec sheet for a fader/motor similar to one that I used: http://www.alps.com/prod/in... Keep in mind that it could vary depending on which one you choose to use.

Hi,
I have an issue with Touch Sensitivity. I'm using an Alps RSAON11M9 motorized fader, with touch sense track, and a teensy LC.
What I have done is I connected the "T" terminal (the touch sense track) to a touch pin on the Teensy, and add a 1Mohm resistor between this pin and an output pin directly on the teensy.
Could somebody confirm I'm doing well? Is there anything else to do? Something to connect to the ground? Or to not connect to the ground?
Thanks for your help

I haven't used a Teensy before, but it sounds like you have it connected correctly.

You don't need to connect ground for touch to work, but it will be more stable if you do connect it to earth. Using a USB cable takes care of that for you. If you start reading the values from the fader, then you'll need to connect one side of the wiper to ground and one side to V+.

Also, here's a pretty good article I found on Capactive touch sensing with a teensy. Just connect to T instead of to a sheet of metal. https://www.pjrc.com/teensy...

Hi,
Thanks for your answer. And thanks for the link That I already saw before but reading again, I realized I missed something important: they say Teensy LC do not require the CapacitiveSensor library. To read capacitance on touch pins, simply use touchRead(pin).
Well, I gonna try this!
Thanks again

Hi,
Got it!!
Well, I first tried using the dedicated touchRead(pin) command: same problem.
And then I discovered that the metal shield on the fader MUST NOT be connected to the ground!!!
Which is not so easy when you have a front panel in metal, connected to the ground somewhere else.... ;-)
So found a way to isolate the fader and now it works perfectly!
it was snicky!!

Nice job! That's interesting, but a good catch. I figured that the fader's touch line would have been isolated from the chassis ground... but maybe not. :)

Hi Cody,
you didnt make my comment public, but im sure you read it. Just wanted to tell you that i fixed my problem with the buzzing fader with connecting the pin1 of the l293d (enable input) to another digital out of my arduino and wrote another if-else statement:

if (potiValOld != potiSmooth){
digitalWrite(motorEnablePin, HIGH);
.
.
.
//your motor driving code
.
.
.
}else{
digitalWrite(motorEnablePin, LOW);
}

Sorry, sometimes I don't have time to look at the comments for a few days. I'm glad you found the issue. Feel free to submit a Pull Request on GitHub if you want.

Hi Cody,

thanks for your work, everything is clearly and my fader works fine on the first run. I have one problem: I used an ALPS RSA0N11M9 Motorfader which is 10K. Sometimes i get a buzz-sound from the fader when its not moving. Buzzing stops if i touch the fader but after releasing my finger it starts again.
I smoothed the pot and fader values (and monitored them) so im sure this is not the problem.

I have no experience with any of this and it's making my head spin. You keep saying easy easy easy but still this project is very daunting. This article was found to help find a solution for controlling everything my guitar sound is wired to in my DAW. I think I'm closer to hot gluing a pre made controller before I delve into this, sadly.

Hi Jon, sorry that the project seems so daunting. When writing the article, I was assuming a basic working knowledge of Arduino, MIDI, and basic electronics. If it seems too difficult, try getting an Arduino starter kit and completing several of the demo projects. Once you understand how the Arduino works and how to assemble a few basic circuits, come back to this project, and I don't think you'll find it to be as difficult.

Hey thanks for the support.

Nice! If i want 8 faders , can i use the same arduino? And When i load mix session in protools for example, have the fader automaticaly recall?, Sorry for my english

Yes, you could use the same arduino, but you'd need some additional hardware to make it work. You'd also need a bigger power supply to drive 8 motors. Try one, then two, then scale up to 8 to help you work out the kinks.

Auto recall should work fine on any DAW, as the DAW will send out the faders position when the project loads. This project won't work with Pro Tools though, because Pro Tools doesn't support Mackie HUI. You would need to emulate Mackie Control with SysEx messages for that.

thank you master!

Nice work on this project! Would you happen to have basic code for just controlling the motorized pot with a standard pot? Touch response not needed. Just looking for a 1:1 linear relationship; pot turns up, fader moves up. Thank you.

The motor is not running through the calibration. I get a very small movement just after uploading code, then nothing. any thoughts?

You might have the positive and negative for the read circuit on the fader reversed (or on the motor), or you might not have enough current to drive the motor.

Try breaking everything down into pieces:
- Turn off the motor control and log the value of the fader. When the fader is up the value should be higher, and when the fader is down the value should be lower. - Then, try controlling just the motor. Make sure that when you tell it to go up that it goes up and not down. (Be careful, because if the motor is stuck and you continue applying power to it, it can fry it)
- Finally, once the other two pieces are working and you understand what is happening with each of them, try connecting it all together to have the fader control the motor.

I got it! thank you! My motor is slower than your was. I needed to increase the delay during the calibration. Min and max values were initially very small. The relationship is pretty good. is there any way to tighten up the control?

https://github.com/codyhaze...

Then remove line 36, 52, 65, and 95-98.

Hello! I need to contact you because I need just that your midi project for my daw Logic Pro 9. When loading the Midicontrol code Arduino gives me error loading because it tells me that is missing in the library captsense what should I do? Thanks Roberto

Hi, you'll need to download the capsense library (http://playground.arduino.c..., add it to the Arduino IDE, and update the code to use the version you downloaded. I wrote this software a long time ago, so it doesn't work with the latest CapSense.

Ok fatto! Ma ora ottengo questo errore! Perdonatemi quindi i fili di canale MIDI da dove li collegano? Vi allego le foto e schermate !!! https://uploads.disquscdn.c...https://uploads.disquscdn.c...https://uploads.disquscdn.c...

I would need to see all of your code to be sure, but it looks like you need to download and add the MIDI library (#include <midi.h>)(http://playground.arduino.c....

...sorry! This is code!

Could you create a pastebin (pastebin.com) and reply with the link? That will make it easier for me to run the code.

If you give me an email address I still think it's easier!

Hello, did the pastebin. My name is Spraylife

A detailed article must contain links to parts used, preferably links for readers to be able to shop

Hi,
Im struggling to find the cap sense library, have you got a link to it?

http://playground.arduino.c...

Ok thanks, i did see that one but it looks very different to when you used it

Yeah, they've changed the API by a good amount since I did this project several years ago. I may try to update it someday, but I can't really update the code without reconstructing the whole project to test.

Hi!

Total beginner here, sorry for the stupid question...
What resistance should the potentiometer have?

It doesn't matter too much. I think I used 1k. 10k should be good, too. Just make sure it's a linear potentiometer. The lower the resistance the more power will be used (Power = Current * Resistance), and the higher the resistance the more noisy the signal may be (which could cause jitter in the fader).

I keep getting this error:

sketch_jul29a:49: error: 'CapSense' does not name a type

sketch_jul29a.ino: In function 'void loop()':

sketch_jul29a:52: error: 'touchLine' was not declared in this scope

sketch_jul29a.ino: In function 'void loop()':

sketch_jul29a:68: error: redefinition of 'void loop()'

sketch_jul29a:51: error: 'void loop()' previously defined here

sketch_jul29a.ino: In function 'void checkTouch()':

sketch_jul29a:101: error: 'touchLine' was not declared in this scope

'CapSense' does not name a type

Any idea what I'm doing wrong here?