In an earlier Instructable you'll see I put together a TDA2030 stereo amplifier. Well I decided I wanted to be able to control the volume by infrared remote. I mounted the amp into an empty desk top computer power supply case. I used an Arduino Pro-Mini I purchased a cheap remote receiver kit and servo off of Ebay. Here's link to the parts
Step 1: Set Up
I was doubtful about many things. Was the Arduino Pro-Mino's output enough to power the servo? Was the cheap 9G servo strong enough to turn the volume pot? I decided to just go ahead and build and see if it would work. The results were fine. It all worked very well. Also I found that my first thoughts concerning the mounting of the serve\o was way over engineered. The video shows how easy the mounting actually was. I found a metal bracket from my bag of salvaged things that with a little creative bending with my needle nosed pliers worked perfectly. The bracket that holds the servo is holding in place just by pressure. there is no actual screws or bolts involved. I the picture of my first idea you see I was building an arch. I ended up using one of the end pieces that held up the arch.
The servo has three wires (brown, red, and orange) The brown is ground, the red is for the voltage and the orange wire is the signal and is attached to the Digital 9 pin on the Pro-Mini.
The infrared receiver has three pins. The voltage and ground are well marked and self explanatory. The pin marked IN attaches to the D-11 pin on the Pro-Mini.
I use a 12 volt AC to DC wall wart power converter. I ran that to a mini breadboard so that could run the amps power from it.
Then I used a LM7805 power supply to provide the servo with 5 volts and a higher current than the Pro-Mini would provide. That project is here
I was sure to tie all the grounds to one ground.
Step 2: The Final Step
You can see in the video how I finally mounted the servo by forming a bracket and the fit was tight enough to the back of the servo no further attachments were needed. To connect the output of the servo to the potentiometer I used a rubber tube that was recovered from a dead printer. It was on a shaft and it was used to move the paper. I screwed on one of the arms (horns) that came with the servo then snipped off the arm and sanded to down. The purpose was to increase the diameter of the servo axle hub so it would fit tightly into the short rubber tube. The rubber piece was thick walled and both the servo hub and the knurled end of the volume pot fit tightly. Also i think it serves the purpose of absorbing any torque induced shock as the servo moves from point to point. There is no slippage.
In case the adding of the sketch through the Instructable doesn't work you can download the sketch for the Arduino Pro-Mini here