About Lenore

Co-founder of Evil Mad Scientist Laboratories

LED Pez Menorah, this time with instructions!

Joyce wrote in this year with her latest Pez Menorah (using our Deluxe LED Menorah kit), featuring a Star Wars theme.

She also wrote up a thorough set of instructions on tumblr, which looks like a remarkably easy way to publish a step-by-step tutorial without using a platform like instructables. It may take some getting used to reading chronologically, but it is effective.

Previous Pez Menorah posts:

LED Metronome


After seeing our Larson Scanner kit, Martin shared this LED metronome project with us. Martin says:

It was designed as a “Visual Metronome”  So a learning music student could help see the timing by watching the green light.  There was to be an optional clicking sound  by using a small solenoid for the ticking – I chose that in place of a speaker for a more authentic sound.

The timing is a standard 555 timer which is fed to 7442 BCD to DECIMAL counter.  Next chip is a 74193 UP/DOWN counter.  When the count hits the last number, it sends a pulse to reverse the count or start over – depending on the toggle switch on the side.

There is also a pot on the 555 to control the speed.  All this was made in one night while I was working the graveyard shift.

The entire LED display was hand wired using a manual wire-wrap tool.

The chip pin labels on the back of the perf board are a particularly awesome relic of a different era of electronics assembly. Thanks for sharing your project photos and video with us!

DIY Snowflake Chocolate Molds with the Othermill

Our friends at Other Machine Co. have put out a mold making kit for the Othermill and posted an instructable for making snowflake chocolates using the online Snowflake Generator that Paul Kaplan of Inventables ported from our Vector Snowflake Application.

The process involves milling a wax positive for making a silicone mold. The beautiful two-tone chocolates are made by putting white couverture chocolate into the details of the mold, and then filling the rest of the mold with dark.

One more technique we could have used for Operation: CNC Snowflake!

CNC Dragonfly Barrette

Dragonfly Barrette

When I saw Simone from Othermill running her machine this weekend, I told her about an idea I had for a metal dragonfly hair clip. She quickly grabbed the file from Sam DeRose’s Light-up PCB Pins tutorial. After carving the texture and doing the cutout, the only other tools needed to complete the project were a pair of pliers to bend the wings and some glue to affix it to a clip. It turned out great!

Robot heart

For Halloween this year, I went as a robot, wearing a silver dress with a slowly pulsing LED heart glowing visibly under the fabric.

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The LED is a one watt white LED, which we’re running at about 50 mA. It has a wide viewing angle, and the star-shaped mount lies conveniently flat. The LED is wired up to the PCB with a pair of twisted magnet wires. Magnet wire is flexible and thin, which makes it hardly noticeable under clothing. It is controlled by ATtiny2313 (running the code from our Mac sleep light pumpkin project) and powered by three AAA batteries. The PCB corners were rounded off so it wouldn’t be stabby.

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The dress was fully lined, which made it very convenient for mounting electronics. I pinned a makeshift pocket onto the liner, and tucked the battery holder and PCB in the pocket. I could feel the battery holder switch and turn it on and off through the fabric.

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The LED was taped to the dress liner with medical tape to hold it in place. An extra piece or two of tape held the wires to make sure there was appropriate slack for movement. (A note on tape: use the good stuff. The cheap paper tape in the off-brand first aid kit only stuck to itself and the magnet wire. 3M plastic medical tape worked great and came off easily.) This makes it easy to disassemble after Halloween.

LED heart


You can find more costume projects in our Halloween Project Archive.

Pumpkin Faces for EggBot

Pumpkin Face

renegade_geek posted a set of Pumpkin Faces on thingiverse for the EggBot. They’re cleverly arranged in layers so that you can hide and show the different eye, nose and mouth options.

A collection of separate eyes, noses and mouths, each set on its own layer, for a customized jack-o-lantern/ghost face to be printed with the Eggbot. These were made to print on ping pong balls. You may need to adjust for eggs and other less regularly shaped items. I have included a “faces menu” PDF so that you can clearly review your choices. This was really helpful in a classroom situation.