Picked up one of these IC test clips on eBay for a few quid. It makes a spectacularly convenient programming clip.
The idea is that you clip it to a chip on a circuit board so you have easy access to the connections for use with test probes.
I’ve got a different use for it though. If you develop a circuit using an Atmega chip (like, say, a circuit you developed with an Arduino but have now moved to a custom board), reprogramming the chip is fiddly. The best way to make your circuit easily re-programmable is to build an ISP header onto your board – it’s just a 6-pin connector that lets you blast new programming onto the chip without removing it from the circuit.
Most of my little circuits don’t have room for the 6 pin connector though, and it’s a hassle to hook up the 6-pin programming connections when you’ll hopefully never have to reprogram the things anyway.
To program the chips on these boards you have to lever the chip out, stick it in a programmer and then stuff it back into the circuit board again. Not the most difficult thing to do, but it can get a bit fiddly, and it’s always a bit dangerous trying to lever the chip out without damaging the chip or the board. The test clip fits over all the pins you need access to for programming though – this clip doesn’t reach the bottom four pins on the chip:
…but it turns out you don’t need to use those pins for programming. So: I dug out a bit of ribbon cable with a 6-way pin header on the end:
Stripped the wires (carefully – they’re bloody thin conductors in ribbon cable):
… and soldered the wires to the right places on the test clip:
A bit of heatshrink tubing makes it all look slightly more perfeshional:
And lo – it’s now a programming clip, letting you reprogram the chip without having to pull the chip.