This project began much like many of my projects at Milwaukee Makerspace have: an off-the-cuff discussion; in this case, with Lance Lamont about a possible project for Maker Faire Milwaukee. After a few rounds of discussion, we came up with the idea of an electromagnetic crane. I decided I’d attempt to build one similar to this style, and that I’d start off with the magnet. I purchased several small electromagnets from Tom‘s favorite website, Banggood. Thus, the MicroMagnetArray was born:
And failed miserably. Running at 18v (50% more than its rated voltage!), it was only drawing ~200mA, and could only lift 2-4 of the 7/16ths nuts I’d borrowed for use as ballast.
So my inner maker came boiling to the surface and yelled at me, “why not wind my own!?”… Continue reading →
I’m working on a project that requires two power strips to be turned on in a sequence. The first power strip powers 6 HDMI displays, and the second one powers 6 computers. The displays have to be on before the computers so they sync properly and get the correct resolution. Since I can’t rely on a person to do this properly, automation is the answer.
My first thought was to use something like a PowerSwitch Tail with a microcontroller to trigger it. (There’s also a cheaper kit version available.) The issue with this solution is that I’d need a microcontroller, and a power supply for the microcontroller, which are more parts, and more points of failure, and take up more space. I also considered using a cheap relay module, but ultimately I was overly complicating the whole thing. Also, I want this to be reliable, and sticking a 5v power supply, a microcontroller, and a relay in a box for three years seemed a little risky.
What I really needed was a “Time Delay Relay” which is a device that can get power, wait X number of seconds, and then power on another thing. There’s a whole bunch of them you can just buy! Time Delay Relays are not cheap though… This one is under $40, but you’ll probably also want the socket, which puts you closer to $50.
Luckily, Milwaukee Makerspace is filled with all sorts of old industrial “junk” and we have a bunch of these sitting on a shelf! Brant (you know, the guy who made an Auto-Off Timed Outlets from an old microwave control panel) helped me find one and get it wired up last week. It works great!
I used a $3 extension cord to provide an easy way to plug it into the first power strip and plug the second power strip into it. There’s a dial that lets you set the delay up to 10 seconds, which is more than enough for my needs.
If I’ve learned anything from this project it’s that even though you think you might have a good solution to a problem, it’s still worth asking others (at the space or on the mailing list) because you may get a better solution, and may even get the parts you need.
If you’re like me, you’ve left a soldering iron plugged in once or twice. Hopefully you’re also lucky like me and it’s never started a fire. Occasionally I’ll grab something off our Hack Rack and take it apart. A) It’s fun and B) it helps cut down on the ever-growing pile of appliances in the East Room. Recently I focused my efforts on a microwave oven. During my salvage operation I managed to extract one plastic fan, two thermal cutout switches, a transformer, the magnetron, a huge capacitor, and the controls. I soon realized that what I had in front of me was a digital timer wired to a normally open relay. I couldn’t immediately think of something to do with it, but it seemed too good to toss or disassemble further. About a week later I decided to wire it to a pair of 120-volt receptacles. Voila. Any appliance with a standard plug can be set to run from 00:01 to 99:99 before powering off. Just press “TIME COOK” then enter the time in minutes and seconds, then start. The relay closes the circuit and the outlets are energized. When the timer runs out, a piezo buzzes and the outlets shut off. The relay on the microwave’s circuit board is 120-250 volt at 16 amps, so I’m fairly comfortable it will handle one or two 40-watt soldering irons.
This weekend, I helped decorate for a Halloween Party at my sister’s house. There’s an odd hallway that connects their main large public room to the rest of the house. It’s used for storage, and has shelves on both sides.
This year, I decided to decorate that area by creating a video wall effect. Something like a Television Control Room of Terror!
To start with, I simply filmed my brother-in-law with a video camera – only from WAY TOO CLOSE! I shot macro video of his eye and mouth. Then I edited the footage to create a custom looping DVD.
In the hallway, I set up multiple monitors. These are old monochrome standard definition monitors that were on their way to the recycling center. They were professional monitors, which means that they can pass a video signal through from one monitor to another, making it easy to daisy chain several monitors.
Next to the monitors, I set up three DVD players (including one car DVD player – hey I use what I got!) to play the three different custom DVDs – Right Eye, Left Eye, and Mouth. Each of the three videos is a different length, so they will continue to drift out of sync. That way, as they loop, the visuals are a continuingly changing experience through the whole evening.
Above the monitors, I set up a video camera on a tripod and fed it to some of the monitors. That way, when party-goers look at the monitor, they also see themselves. Having feedback on some of the monitors adds a sense of interactivity to the project.
After the monitors and DVD players were all set up, I covered the rest of the shelving with black paper. In a dark hallway, lit only be black lights, it’s a great effect of creepy images floating in the hall.
If you want more details on this project, I made a full step-by-step write-up on Instructables.
Last summer I came across a collection of car parts at a garage sale; instrument clusters, lights, gauges, and some digital clock displays. For $5, I became the proud owner of a JECO Japan, vacuum fluorescent clock display. The plastic housing held all the clock electronics, membrane buttons for setting the time, and a four-pin connector. After powering it up, I realized one of the pins could be used to dim the display, which is a pretty nice feature to have.
I’ve worked on it off and on for a few months, but finally decided to finish it this weekend. On Saturday, I tweaked some dimensions and laser-cut the final enclosure. I wasn’t happy with the button holes and text I had on the front of the first iteration, so I got rid of them for the final. You can adjust the time by slipping a jeweler’s screwdriver or a paper clip through a gap in between the plexiglass sides and pressing the buttons to add hours or minutes.
I added a small single-pole, double-throw toggle to switch between bright and dim, then soldered the connections before closing it up. The whole thing is clamped together by a single #10-32 machine screw and a wingnut. The final result doesn’t look half bad.
Join us for The Greatest Show (& Tell) on Earth at the Wisconsin Center September 14th & 15th, 2019. Admission is free. Co-hosted by Milwaukee Makerspace and the Betty Brinn Children's Museum.
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