Audio breakout cable for ipod/iphone

(update) I inadvertently said I got the 4 conductor plug at Jameco – it was Mouser, and is listed correctly, with the part number in the blog. Have you ever wanted to plug in a professional studio mic to your iPod touch/iPhone? There may be a commercial solution, but I…

Cheap Photo Studio in a Box

With all the pics I’ve been taking, I’ve been looking into getting a Portable Photo Studio. Depending on the make/model they can cost from $50-$100 (way too much for me). And where to store it all? I made my own for less than $20, and it’d be cheaper/free if you…

How to invert a photocell’s resistance

It takes lots of experimenting to find the right values of the parts.

Resistor Color Code Chart

Keeping track of kit parts

This may be an obvious one, but I started doing this a while ago and it helps. When building kits, I feel I waste time after soldering in one component, and then hunting down the next one. Then I started laying them out ahead of time, which helped a lot,…

How to wire up a RCA patchbay

I get a lot of e-mails asking about hooking up patchbays to bend points. Here are a couple different methods. Remember – you can expand these ideas across multiple patch panels, hook up switches and pots in between, etc. A) In this method, each RCA jack is wired/soldered to an…

Adding a 1/4in. output & volume knob

Keypad matrix diagram

This is for a large 20 key keypad, but the theory works the same for smaller keypads. You can use an ohm meter to see which rows & columns get connected with each button press.