how to make a powerprobe?

I was wondering if anyone had a schematic for a test light like the PowerProbe. Something that will beep and change colors and the ability to send either a negative or positive pulse. I can make a computer safe test light with a dual color LED but can't make it beep in a difference tone with + and _ signals. I just want to make something for myself as project. Any ideas? ieSpell rocks.

Much cheaper to buy one.

I have to say thanks to h8nbnvs2 and the wonders of Google Search! I'm about to buy a set of door trim tools from them for a TENTH of what Snap-On charge in the UK.

I just want to make it for the heck of it? To see if is possible to make something like the PowerProbe II at home. h8nbnvs2 is my co-worker, he saw when I posted the question and decided to mess with me by suggesting I buy it at Harbor Freight because he knows I buy there. I must have like 5 sets of the plastic yellow pry tools from there.ieSpell rocks.

Are their tools any good? I've just ordering some "Philadelphia" brand trim pop tools, they are about 1/10 the price of Snap-On in the UK.

Howie, harbor freight does sell some junk.  Some things they sell are pretty decent and well worth what you pay for it.  I got my panel tools from them.  If it is the set of 5 tools for around 10 USD, they are very well worth what I paid for them.  If it is a mechanical tool from there, I buy 2, 1 to use now and one to use when, not if, the first one breaks.

Thanks for the comments Craig, part # 66188, $19.99, those 6 from Snap-On would cost me $180 here, so what have I got to loose? Most of my work here seems to be interior take-downs and I lost 3 in the last 2 months, now I'm after a good wire stripper with a small head for confined spaces. Out of interest, Ford Transit Connect vans, trackers hand dissembley, R/H drive Mazda 6, the same pop the glovebox and there's a fusebox, L/H kick panel with constant and ignition.