Cardboard Knife Switch

For many electronics enthusiasts there is a special place in their heart for knife switches. At least that’s the case for educators I’ve worked with the past decade or so. My guess is it has to do with the simplicity of the knife switch in explaining how a circuit works. Is the circuit opened or is it closed? A knife switch provides a visual demonstration of this like few other switches do nowadays.

Knife switches are not used for most modern day circuits as they have been replaced by switches that are safer at high voltages, but since we work with low voltage circuits in educational settings this DIY Cardboard Knife Switch is perfect.

I’ve talked to a few educators and heard complaints about how expensive the old style knife switches are. (You can buy new “cheap” plastic versions for about $2 per switch, but the ceramic ones are often $10 or more.) I thought I’d lower the curve by creating a cheap DIY version that can be made with Maker Tape.

There’s a template that can be used to make one from cardboard or other material that’s got some rigidity and thickness to it. Cardboard is great, foamcore could work, cereal boxes are too thin. The template expects some cardboard and a way to cut it, which could be an X-ACTO knife, some scissors, a razor blade, or even a laser cutter.

Once you have your four pieces you attach some conductive Maker Tape, poke some holes for the brass fasteners to go through, and you’re nearly done!

Assemble the four pieces using the brass fasteners to hold them together and to act as a pivot point for the lever and you’ve got a knife switch. It may help to pinch the top of the two outside pieces a bit narrower so the knife is guided into place a bit better. (You’ll see this tip and more in the PDF guide.)

Besides the Brown Dog Gadgets Project Database, you can also find this project on Instructables.


Instructables + Laser = ????


So here’s the deal friends… Ben Nelson, fellow maker, DIY enthusiast, and Milwaukee Makerspace member, has won his fair share of contests over at Instructables, and it’s prompted me to give it a try as well, so I present to you my first Instructable: Creating Random Art for Puzzles.

And I’ll be totally honest, the main reason for me publishing it was to enter this contest to win a laser cutter from Hurricane Lasers. (I have no shame in telling you that!)

Ever since the Makerspace got a laser cutter, I’ve fallen in love, and it’s become my favorite tool, possibly even surpassing the RepRap. (Shhh, don’t tell the RepRaster 5000 that!) You’ve probably seen a few of my posts about things I’ve laser cut. Of course lately the laser cutter seem to break down every other week, so getting time to go to the space when it’s working is tough. Luckily, my friends at Lovesick Robot Studios helped me out with this project.

Laser-cut puzzle coasters

When I started on this project, I wasn’t even sure where it would go, but I wanted to explore the concept of introducing random elements into my art and see where it would take me. Well… this is the first stop: puzzles created with random art.

Puzzle: Solved!

Of course if you know me, you know I also love making coasters… so I made puzzle coasters with random art in addition to a normal puzzle. (The “normal” puzzle was made with a printer, some board, and an X-ACTO knife. All the details are in the Instructable.)

Puzzle? Coasters? Both!

So here’s the deal friends… I’d really appreciate if you vote for me in the contest, because if I win, I’ll get my own laser cutter… but rest assured, I won’t just keep it to myself. If you need something etched or cut, well, I may be able to help you out. I mean, if I win this contest. So yeah, I’d appreciate your vote.

So go to the page to vote. See the image at the top of this post which shows where the “VOTE” button is.) Also, since I took my sweet time, we’ve only got two days…. Voting ends the 20th, so don’t put it off… vote now! Don’t see the vote button? Make sure you log in. Don’t have an account? Create one!


Update: As of 2012-09-28 I have not been chosen as a finalist. Oh well.