Arduino-powered remote volume control for my vintage stereo receiver

When I ran this and looked at the serial output, I was able to see the hex values received
from my universal remote when I pressed the up/down volume buttons. You can see the values here:

All that was left to do code-wise was to combine the stepper motor code and the IR code to make the
motor turn in either direction when the remote button was pushed. I found this tutorial
that was doing almost exactly what I was, but using slightly different hardware. I borrowed some
of this code and combined it with some from the stepper motor test. Here's what I ended up with:

#include <Wire.h>
#include <Adafruit_MotorShield.h>
#include <IRremote.h>

// Create the motor shield object with the default I2C address
Adafruit_MotorShield AFMS = Adafruit_MotorShield();

// Connect stepper motor with 32 steps per revolution
// to motor port #1 (M1 and M2)
Adafruit_StepperMotor *myMotor = AFMS.getStepper(32, 1);

/*----- Variables, Pins -----*/
int receiver = 2; // Signal Pin of IR receiver to Arduino Digital Pin 2

/*-----( Declare objects )-----*/
// Setup of proper sequencing for Motor Driver Pins
// In1, In2, In3, In4 in the sequence 1-3-2-4

IRrecv irrecv(receiver);    // create instance of 'irrecv'
decode_results results;     // create instance of 'decode_results'

void setup()
{
  irrecv.enableIRIn(); // Start the receiver
  Serial.begin(9600);  // set up Serial library at 9600 bps
  AFMS.begin();  // create with the default frequency 1.6KHz
  myMotor->setSpeed(200);  // 200 rpm   
}


//main loop to listen for remote IR signal and move motor

void loop()
{
  if (irrecv.decode(&results)) // have we received an IR signal?

  {
    switch (results.value)

    {

      case 0xCBA816E1: // UP button pressed
        myMotor->step(35, BACKWARD, SINGLE); //I need backward motion to turn my volume knob up
        //delay(200);  this was in the original code but I decided no delay was better
        myMotor->release(); //saves stepper from using voltage and getting hot at rest
        break;

      case 0x43D69629: // DOWN button pressed
        myMotor->step(35, FORWARD, SINGLE);
        //delay(200);
        myMotor->release();
        break;

    }

    irrecv.resume(); // receive the next value
  }


}/* --end main loop -- */

You'll notice there are some notes in the code. One important thing I learned is that stepper motors
stay energized and therefore get hot when sitting idle. I didn't want that since my motor would almost
always be idle; I found that the release() bit of code would de-energize it when not moving.

My hardware and code was now working as intended!

Next up I needed to make a bracket that could hold all this business together and attach it
to the receiver, while leaving the receiver intact so it's 100% removable. I had some .05" aluminum
from a previous project which seemed perfect for the job. First I drew out the lines to cut/bend:

Out in the garage, I made use one of the useful tools in my arsenal: a Dremel with a cutoff wheel:

After filing the edges clean, I made the single right-angle bend in the vise:

Here's what I had pre-drilling. I actually made a measuring mistake, so I ended up re-making
the bracket, and like a cooking show, this is not the one I ended up using.

For the second one I decided to use my "nibbler," a tool which has a funny name
and is very useful for cutting straightish lines in sheet metal.

Ollie waited (somewhat) patiently for me to do all this work.

I decided I didn't want the Arduino to be powered on all the time using up energy,
so in order to install a power switch I cut one of the traces from the power jack and
soldered a toggle switch in between.

Here you can see the toggle and the IR receiver, which I used hot glue to affix
to the back side of the bracket, just protruding to catch the signals.

The completed unit, assembled and ready to install!

I hadn't really thought ahead about a drive belt, and had figured a standard rubber band would work ok.
I didn't consider all the stretching the band would do though, so when the volume changed directions
it would take several steps of movement to get the volume knob moving. I ended up deciding o-rings
would probably do the trick nicely.

I used string to measure around both pulleys and ordered a few different sizes of o-rings around
that circumference. One of them fit very well, without exerting too much force on the volume pot,
and I doubled it up to get more friction.

The bracket is in place and the unit works great! I fiddled with the number of steps the motor used in order
to get a good amount of granularity while also not taking forever to turn the knob a good distance.

A user asked me for a wiring diagram so I made a quick one here:

Here's a video of the volume control in action:

If you can't see the video please click here