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Cutting Fan Blades

Here’s a fun project. My uncle asked if I could cut down some ceiling fan blades to be about 38mm shorter. Without knowing the material or how I would do it I said “Sure, I’ll give it a try!” and he was fine with that. I guess he purchased a new set for his fan thinking they were shorter but they were the same length as the existing blades, so it was low-risk if I failed.

My first idea was to build a jig and laser cut the ends off. This would (in theory) make sure all the cuts matched exactly. Since the cuts are curved, I thought this would be a good idea. The blades are plastic though, and I didn’t know what plastic. I gave up on this idea. (I think they might be ABS, but I don’t know for sure.)

So what I did was used my desktop scanner to get an image of the blade, then printed a paper template I could tape to each blade to do a cut on the bandsaw. (Note: I have a pretty low-quality bandsaw at home, which is fine for rough cuts of thin materials, but not exactly precise.)

I taped the template to each blade and cut them one by one. I did better on the first two than the third, and probably better on the first one than the second, so I had three cuts that were not exactly matching. No matter, on to the disc sander!

Did I mention the blades are plastic? I ended up taping all three blades in a stack so I could sand them evenly. It mostly worked. I had to take breaks to allow the plastic to cool and use a razor to keep cutting off the gunked up plastic on the bottom of the stack, but I think I got them really close to being even with each other. (Apologies for the lack of process photos, I was concentrating pretty hard on getting them right.)

I cleaned up the edges a bit with a razor, but didn’t actually shape them like the original ends were. Hopefully these will work. If not, it was a (somewhat) fun challenge to do something I’d probably never otherwise do…

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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.

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Reflect-O-Scope

The Reflect-O-Scope was an interactive museum exhibit I worked on a few years ago. It was a fantastical machine that allows users (typically children) to slide materials under a microscope and examine them. The materials were from the sponsor of the exhibit and consisted of specialty tape materials adhered to plastic boards.

One of the original ideas was to allow for focusing, but that got scrapped. We figured kids would put almost anything under a microscope, their hand, their little sister, etc. Focusing meant a moving mechanism, and it was deemed to complex at the time.

The sculptural build was done by John McGeen and Austin Boechler. My focus was on the hardware and software. There’s a USB microscope connected to a computer and then a small HDMI display in the “goggle” shaped piece that the user looks into. It’s all a bit “periscope” like in design.

The original design also had a secondary monitor (a large TV) that would be mounted further away, so people could see weird things on the TV and it would draw them over. Lots of features got killed due to lack of time or other reasons. Most of what you see on a museum floor probably started out a lot more complex when originally designed, and then simplified as time goes on.

I wrote the software, which is just an application written in Processing that automagically launches at boot up, runs full screen, and shows the output from the USB microscope. There’s also a companion application called “List Cameras” that can display all the connected USB cameras and all of the possible resolutions they support. This is there in case the USB microscope ever needs to get replace. The exhibit tech just needs to run the application and then edit a config file. No recompiling of the application is necessary.

One more fun addition was a white plastic tube running along the outside with some NeoPixels in it featuring some funky color runs to add to the fantastical nature of the piece.

One of the nice things about this component was that the software was created in-house, so the component could be replicated easily without additional license fees. (We had an amazing software partner we used for the complex things, but simple stuff was done, when possible, in-house by the tech team, which was basically me.)

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VIDEO FACE [AVM-312]

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One of the projects I built for Maker Faire Milwaukee in 2019 was VIDEO FACE [AVM-312] which is a companion piece to AUDIO FACE [APC-320].

This piece came about because my sister gave me a box of old security cameras. Specifically, analog video cameras. I brought them to Brinn Labs and hooked them up to one of my displays, and they worked fine. They just need a 12 volt power supply and they have composite video out. If you mix the two signals from two cameras together into one output you get a garbled and mixed signal, but if you add in a resistor and potentiometer, you have a way to control the amount of signal that the second camera leaks into the stream to mix with the first camera! (It’s an analog video mixer.)

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I considered adding resistors and potentiometers to both cameras but for a standalone exhibit that would have allowed people to dial it down too much and the projector that was connected would probably have gotten confused and lost a recognizable signal and just shown “NO SIGNAL”, so I went with one camera full strength and the other variable.

Construction of this was very slapdash, using scrap wood I found at Milwaukee Makerspace one night. As yes, it’s supposed to look like a face, I mean, it’s in the name, it’s got two eyes looking at you, a nose with controls and a mouth, sort of…

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During Maker Faire I had it hooked up to a projector that had analog video input. (Yeah, those are probably getting harder to find, but I have some interesting old equipment.) For other events I just used one of the small television sets I have on hand.


I loved doing these quick and dirty interactive projects, back in the old days, you know, before the pandemic.

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Campfire Badge

If you loved the Rocket Badge they you’ll probably like the Campfire Badge. And of course if you do like the Campfire Badge you can grab it from the Brown Dog Gadgets Project Database.

I started with this campfire from SVGRepo and with a few modifications, I think it works well for the badge. Above is the top part of the badge, and below is the bottom part with the circuit. You print both parts and do a bit of folding and taping to create the two layers.

The circuit consists of a red LED, a CR2032 battery, and Maker Tape to connect it all together. There’s also a paperclip that can hold the paper switch closed to keep it turned on.

This one has an extra illustration to show the layer assembly. I’ll admit, I’m not the greatest illustrator, but I’m getting better. Most of my work doing vector illustration in the past 10 years has been for technical drawings used for digital fabrication, not for… art. Creating these illustrations is a lot of fun though, and I’m glad I get to do it.

Like many other projects for Brown Dog Gadgets, we provide a full-color template and a black & white version if you want to do all the coloring and decoration yourself.

These are fun projects that can be done at home or in a workshop setting using cheap materials. More badges are coming…

Stay Tuned!