Is it just me, or does everyone have trouble with accumulating junk in drawers, boxes, under beds, and even coat pockets? For some reason I hold onto all sorts of stuff, hoping that someday I'll find a use for it. Usually I can't find it when I come up with an idea, but that's another story.
Anyhow, I recently had a need for a small serial data logger and thought one of the retired zipits from junk box 42, under the bed might be just the ticket. Over the years I've accumulated a few zipits with various disorders such a dead pixel row or whatever. That wouldn't be too much bother for something spending most of it's time out of the way, logging things.
Rather than build another special purpose cable I decided to go with the original dock from mozzwald, albeit with a tiny modification to run the ttyS1 serial Rx line out the through the dock power connector instead of 1.8V. I've had the disassembled dock and header pins for like forever, and finally found someone with the skilz set to solder the pins and the tiny jumper wire, move the dock detect resistor aside, and cut the exposed 1.8V trace on the other side of the board. There's even some leftover solder blobs to rejoin the cut trace if I change my mind. Heh, unlikely.
Now I have a row of 3 pins (GND, 3V, Rx) on the power connector that exactly match what I used in the custom serial GPS cable I made once upon a time. I only need Rx and GND for the current logging project, but who knows what might tempt me in the future? If it needs power, I've got it. If you zoom in you can see the cut trace above the 1V8 pin in the image below.
And here's the formerly retired zipit (with a dead pixel row) hooked up to a test contraption assembled from other junk box parts. For some reason the only serial cable I could find came with a 25 pin connector on one end. What in the world was I thinking when I kept that one?
I also dug up an ancient 300MHz laptop with a real serial port to say "Hello" to the zipit and prove the board mod works. My actual plan only requires the red and black wires for 3V TTL comms, so it'll be significantly less clunky.
There's more to tell in this story, but for now I just wanted to drop some pics before I lost track. Hopefully I'll find the time to finish.