So you’re really looking for that [Norman Rockwell] Christmas and want to set up your train to encircle the Christmas tree this year. The problem is that all you’ve got is an old LEGO train set and not enough track for it. You can’t just buy some more, because the technology has changed; or can you?
[Chris] was dismayed to find that newer LEGO train sets have gone to battery operation rather than drawing power through metal tracks. The new tracks are plastic, and buying extra segments of the older version is cost prohibitive. He figured out a way to add power conductors to the new track pieces.
It turns out the design of the new tracks matches the old, except they’re all in plastic instead of having metal rails. He bought a plastic add-on set, then picked up some copper foil from the hobby store which is meant for stained-glass work. It’s adhesive backed, and after working out the best way to apply it, he coated the rails with the stuff. As you can see above, the new mates perfectly with the old, and keeps that locomotive chugging along.
If you’ve got copper foil left over after this hack, there’s tons of other uses for it. Perhaps building your own flex sensors is worth a try.
[Patman2700] has a nice scope for his paintball gun that uses a red dot instead of cross-hairs. The problem is that he kept forgetting to turn it off which ended up running the batteries down frequently. His solution to the problem was to get rid of the toggle switch used to turn it on and replace it will a home-made momentary push button switch. Now he presses the switch to aim and doesn’t waste juice when he’s running around, trying not to get pelted with paint.
Since this is used outside he wanted it to be water-tight. The switch is built using materials we’ve seen in previous diy switches; adhesive-backed copper sheets for conductors, foam to keep them separated until pressed, and plastic as a support. Copper is applied to the plastic base, with a ring of foam separating the base from the second layer of copper. When squeezed, the two layers of copper come in contact to complete the circuit. To make it work a bit better [Patman2700] added a dab of solder in the center of the bottom copper layer so there is less distance between conductors, and used extra foam to build up a bump in the center of the assembly for a better ‘button’ feel. The whole thing is encased in shrink-wrap with the seams sealed with super glue to keep moisture at bay.