Spent a good deal of time in the wee hrs trying to hack a couple of IR sensors.

This is — again — part of the Talrik project I’m putting together. The kit is designed to be ulta-cheap, but that means it is a bit more challenging than the usual. But it’s not as tricky as putting something together with straws and bits of aluminium (I takes me hat off to people that do that sort of thing .

The idea is to take a cheap digital IR sensor — that returns a yes/no via a Schmidt trigger stage — and return it to a pure (and more expensive) analog version. You’ll then be able to determine the strength of returned IR signals and maybe tell how far away that wall is.

The sensors in question are fairly big — if you call an ant "big" — but I’m finding it a bit difficult to operate on the 10mm x 10mm pcbs inside. The idea is to cut 1 track and solder 2 pieces of wire from internal tracks to output pins that, themselves, are only 5 mm long.

Oh, and the other thing — since the whole thing sits inside a metal can, you must be careful not to run any bare wires into the container, or across any of the tracks on the tiny pcb, either.

Since the output pins are less than 1 mm from metal on all sides, this has proved to be a bit of a challenge to those of us who consume more than 10 cups of coffee between midnight and 5 am. :}

Anyway, the following are some pix of the operation so far. I made up a simple 10x "microscope" to attach a webcam to, just for the occasion. It’s amazing what you can make with a couple of lenses and a toilet roll or 2…

The 2 IR sensors. Each can is about 10mm cubed:

Opening up a can of worms:

Close-up (via "microscope" of the pcb inside):

The 3 output pins appear in the top rh of the picture. You have to cut the trace from the bottom-most of these, and then solder that pin to the lhs of the nearby cap, then solder a wire from the topmost pin to the enclosing can.

Simple!

After a bit of a struggle, I removed the pcbs from the cans altogether. The first problem was — no soldering iron could reach anywhere inside the can.

The next step was to find tinned wire fine enough to solder to the cap. OK — look inside a 240v wire. The next photo shows the 2 pcbs with a small piece of wire double-looped around the 2 output pins, all ready to solder.

I went for orienting the 2 wires in different ways in each IR sensor. At least one of them should work out right (i.e. no shorts with the can or tracks).

Finally, a "microscope" view of the 2 wires soldered in place. Some excess wire now needs to be clipped off with a very small set of nail-clippers.