Tinkering with MIDI control with Arduino

D'ya remember that Pod guitar effects unit I got a while back?

Today I'm tinkering with a homebrew way of remote controlling some of it's parameters using an Arduino Nano and MIDI.

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#ElectronicsCreators
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This isn't the only way to do it.
It's probably not the best way to do it.

But it's how I do it.

[ericblenner-hassett]

You used to find in the back of Guitar Mag advertisements for pedal ' blanks', empty pedals with a pot already mounted. The problem back then was add $10-15 plus shipping and you could just buy a comercial one. Got to love the thinking in the mid-late 80s. Check the China sites to see if you can find the volume pedals.

[Bob_Burton]

Don't worry about the pot not turning through a large range of angles. You can use the map() function to output whatever range of values you need based on any input range

[SidneyCritic]

You could 3D print a roller and mount to push the rack closer to the gear, but if that's not good enough you could cut out all the bad stuff and 3D print new modified stuff to replace the bad parts and just glue/screw them in place.

[TriggerThat]

About the pedal and the pot problem... You could use and infrared led emitter and receiver and attach a piece of plastic to the pedal that slips between them that goes for fully transparent to black. Berhinger is using such a desing in the X V-Amp guitar pedal.

[AnotherMaker]

That pedal is ridiculously cool. The meshing part could probably be fixed easily but the gearing is probably a deal breaker. I'm guessing you could build something out of wood that would meet your needs a little better.

Then my next thought is that you could use something like a MCP4131 digital potentiometer chip and a rotary encoder. That would get rid of your need for the pot to have any sort of specific turn because you could set the ratios in software. There are good arduino libraries and examples for that chip.

But most of all, thanks for the midi primer. I've been around it all my life but other than a little software tinkering, I've never used it.

[lucylastik]

An idea I've been toying with is to do away with moving parts all together. Get one of those ultrasonic range detectors, mount it facing upward through an aperture in the pedal then just move your foot up and down above it as if there was a pedal. Simples. The arduino will have a library for it, just replace the a/d code in your program with the digital read from the sensor.

[hirsutusi]

Two suggestions:
Fix the poorly meshing gears with a stiffener glued on the back of the rack (rack and pinion). The stiffener would be at right angles to the back of the rack, the hole in the pedal base would be changed from a slot to a tee.
Change the map statement (it would be helpful if you turned on line numbering in the IDE) visible at 5:30 to cover as much of the pot range as necessary. Hopefully that's a linear pot.
Tony.

[DogRox]

Good video! :-) here's an idea you can do what I did a long time ago, I picked up an old volume pedal from a junk place, and made it into a wah-wah pedal using a flanger schematic that I modified. But for your case you would just really need the volume pedal itself and then you can put your electronics into it. That would be more convenient than the long hours of printing out something that may not work. :-)

[macdaddyns]

Ditch the mechanical and rig up a hall effect on the pinion. no more dirty pots either. or constrain the limited rotation you are getting with current setup. ie 25% rotation to the 127 values.
cool project1

[RichardSloan]

Use elastic to tension the rack, then find the lower and upper value that get output from the pot, and scale accordingly

[frankowalker]

You might also try low voltage sewing machine pedals, Kid's toys and such.

[stevesfascinations]

Very nice project. I have been tinkering with 3D printing as well. I think the top gear is not as strong as it should be and is flexing away from the gear attached to the potentiometer. Would you be able to adjust the angle towards the potentiometer gear by using a heat gun? Could you add a metal support (i.e. piano wire heated and imbedded into the plastic) to prevent this from flexing in use? I am looking forward to how you solve the problem! I used the timing belts on a CNC machine and it worked great. It would be pretty easy to use that as a solution as well. Too bad 3D printing takes so long and has a few problems while printing. I have found a RC Aircraft iron to help with the rough areas. This iron was used to iron on mono-coat on the plane wings and other panels. It works quite well as a 3D print cleanup device.

[matambale]

Perhaps the top of the rack, where it joins the step, should be on a pivot, and the bottom of the rack should be lightly tensioned against the pinion with a small spring.

[JohnSmith-bbnp]

Have you thought about a slide potentiometer and a mechanism to work it? Maybe alter the foot pedal with the slide pot going up and down? It could eliminate the rotary pot problems you are having now. And don't electric guitars have a bar you can jiggle that does the same thing?

[MrFlint]

Interesting to hear how long it took to 3D print the box. I have made an almost identical pedal out of 3mm plywood in about half an hour.

[matambale]

It must be MIDI Foot Pedal week - Adafruit just shared a design a couple of days ago.

[jyvben]

Could have split the ground box halfway and added some interior overlap aiding in sticking it together.
Can still add an interior layer tall enough to strengthen the case and at the same time hold the rack pin against the gear.

[TBL_stevennelson]

I would use a string and move the pot to the end. Extend the pot nobe so you can add two pieces that the string can rap around. If that doesn't work then start again with something else that looks promising

[dflat]

I've never worked with 3D printed parts but would worry that a 3D printed pedal would break in gigging conditions. I have made a similar device to your Arduino using an ATTiny85 which converted the pedal resistance to various MIDI CC messages but used a commercial Yamaha FC7 as the input device. The Yamaha FC7 is very sturdy but has a very long throw so am not sure how suitable it is for a wah effect. The good news is that you can modify the response curve in the Arduino software!

[crayzeape]

Maybe use a bit of op amp action to translate the limited range of the potentiometer into the full voltage range that you require.