In a minor diversion from the norm, I thought I'd post something showing a quick 5 minute hack I made a short while ago.
As you may be aware if you look in on my blog I've been working on building a modular-tile system for a wargames table.
I have a small attention span, so as always I get distracted. Despite not having finished all the tiles yet, I've already started building some scenic pieces to add dimension to the table surface.
Inevitably, this has lead to building some hills.
The hills themselves I'll cover in another post - this one is all about the hot-wire cutter I used in the process.
When I got my cutter out of storage (it hadn't been used in a while) I was irritated to find that the battery had gone flat.
My hot-wire cutter may differ from yours - it#s basically a handle with a twisted pair of cables which end in spade connectors:
...in order to attach to the terminals of a 4.5v battery:
Now I honestly have no recollection of the thought-process that led to this, but I ended up devising (probably via wondering if I could buy a PSU of some sort) a means of safely mains-powering the cutter using an old USB cable and a discarded phone charger.
It goes like this. The hot-wire cutter requires a 4.5 battery. USB runs at 5v. "Near enough for Jazz" as the saying goes. Cut the Micro-USB end off the USB cable and strip off the outer insulation. You'll find four very thin wires inside. You're interested in the red and the black only. You can ignore/chop off the others.
All I did was solder the red and black wires to the spade connectors, wrap a bit of tape around them in order that the spades can't touch each other and - JOB DONE! You can see in the photo below where the red wires from the h-w cutter join the green USB cable, wrapped up in a bit of masking tape.
It works like a dream. Not only do I never have to worry about flat batteries again, the spade connectors weren't that reliable anyway and my cable is now 1m longer to boot.
RESULT!
More "quick tips":