Make an audio looper for under $20
Step 1: Gather Your Parts
Get all these parts, available from your local Radioshack:
1. 20-second recording module, part #276-1323
2. Two output jacks of your choice (I used 1/8" mono phone jacks)
3. 1 SPST toggle switch
4. 1 (or more) N.O. momentary pushbutton switches
5. 1 9V battery
6. A cool box/container to put it in
7. Suppplies that I assume you already have: wire, wire clippers, solder, a soldering iron
Step 2: Explore and Prepare the PCB
This is a drawing I made of the small circuit board that is the entirety of the recording module. It has a little speaker, 9V battery clip, pushbutton switch on an attached mini PCB, another pushbutton switch attached to the main board, a black-blob IC, and various resistors, capacitors, and a transistor.
Step 3: Surgery!
Pry the little tabs up which keep the pushbutton on the main board. They are on the back of the board. The button itself should come off really easily.
Cut the wire leading to the speaker at point A, or you can simply desolder where they join to the PCB.
Locate R3, which is labeled on the board itself. If you can't read the numbers on the board, it's the resistor at the top, if your board is oriented like the picture above. The lead on the inside, point C, is where you will solder one wire. Attatch the other end of that wire to one lug of an SPST toggle switch. Attach another wire between the other lug and either one of the points where the speaker attatches to the board; mine is at point B. This is the loop connection.
Step 4: I/O
Here's where you give your looper ears and a voice. Solderin two wire at each point where the speaker wires were. At the end of each, attatch the audio jack of your choice: 1/4", 1/8", RCA, etc. I used 1/8" minijacks.
Some optional steps:
1. Detatch the existing pushbutton switch on the smaller PCB at SW2. I did this and replaced it with an easier-to-mount N.O. momentary pushbutton switch.
2. Make a new one-shot switch by soldering directly to the exposed traces where the button on the main board used to be.
Step 5: Finished (almost)!
And there you have it, a finished looper. All that's left is to house it in something. I put mine in a Fossil company watch tin. These are great for smaller projects like this; they're compact, easy to drill, and are funky-colored. Of course, spray paint is always an option.
To record, hook up some sort of input device to either jack, hold down the momentary puchbutton switch you either did or didn't wire into SW2, and speak/puch play/press a key/whatever you're doing to make sound. I wired the headphone jack on my laptop to it and play clips of recorded audio. When you're done recording (up to 20 seconds), let go of the button, and flip the toggle switch (after plugging a speaker up to the other jack). It will loop continuously. Some cool percussion loops can be made using this simple method.
The looper has some quirks associated with it, but i'll let yoou figure them out, it's more fun that way.