If you have a cheap generic flash MP3 player with a voice recording feature like this

you can mod it to accept a standard microphone. Great for lo-fi podcasting. First open it up. Inside you’ll probably find something like this:

Here’s a close up of the tiny built in microphone. We’re not going to be needing that.

Carefully unsolder the built in microphone and solder a short length of shielded audio cable in its place. If one pad looks more like a ground pad than the other (see all that extra copper around the upper pad?) solder the shielding of the cable to that.

Modify the case so that the cable can pass through the microphone hole:

And put it all back together. I soldered an inline 3.5mm jack socket to the other end of the cable to suit the microphone I was going to use. Here’s how it looks:

You may want to secure the cable to the case in some way otherwise strain on the cable is likely to tear it from the PCB.

How does it sound? Er, not that great actually - but much better than the built in mic which was really muffled and distorted. Listen to it and decide whether it’s worth mutilating an MP3 player for: flashmp3michack.mp3. The level isn’t adjustable so you need to play around to find out where the microphone should be placed in relation to the sound source.