Hack-O-Lantern

October 28, 2012

Halloween fast approaches, and I still haven’t managed to make that electroluminsencent Riddler costume I’ve been dreaming about for the last two years. But this year I did manage to come up with a nifty Hack-O-Lantern that uses an Arduino and a pair of diffusers that I printed on my MakerBot Replicator. Here’s what the animation looks like, including my new favorite function, derp().

My apologies for the soul-deadening ambient light in the video. The Hack-O-Lantern looks a lot cooler in person, although if I had more time I’d try to boost the voltage to the LED’s and brighten them up a bit. Right now they’re running off straight off the Arduino, and I didn’t want to burn out any pins by driving too much juice. Maybe next year.

You don’t need to use an Arduino to use these diffusers: if you’d rather just stick a couple of LED’s in there with a watch battery taped to the leads, that will work just fine. The LED’s in the top photo are running in series off 4X 1.2V NIMH 2500 mAh rechargable C cells, and they look great.

The diffuser has a slight lip on the back that you can use to score your pumpkin’s flesh before cutting.

Nightmare fuel, anyone? Here’s all 14 LEDs soldered to hookup wire, fed through the pumpkin’s eye holes.

Once I connected the LEDs to pins 0-13 on an old Arduino Duemilanove I had kicking around (SCORE for finding a set of headers I’d forgotten I ordered six months ago), I put the whole contraption in a plastic bag so the pumpkin guts couldn’t short the hardware.

Working inside that cavity gives you a lot more respect for brain surgeons.

If you’ve carved a pumpkin recently, you’ve probably got some seeds kicking around. Here’s what I’ve been doing with them lately:

Zheng3 Szechuan Pumpkin Seeds

approximately 1.5 cups of pumpkin seeds, washed.
1 tablespoon doubianjiang
1 teaspoon light soy sauce
1 teaspoon hot chili oil
2 tablespoons peanut oil
1 tablespoon Szechuan peppercorns

Mix everything except the peppercorns in a bowl and toss to coat. Set aside for an hour to marinate.

Toast the peppercorns in a wok over medium heat until fragrant. Crush with a mortar and pestle.

Spread the pumpkin seeds and marinade evenly on a flat baking tray. Bake at 350° for about 20 minutes. Sprinkle with the crushed peppercorns and serve.

If you can’t find doubianjiang and you’re not willing to wait for a shipment from Amazon you can probably substitute some garlic powder mixed with Sriacha rooster sauce.

Approximating the flavor and mouthfeel of Szechuan peppercorns is more difficult. Try this:

Dip a jalapeño pepper in powdered laundry detergent and suck on it for 30 seconds. Then put your lips across the terminals of a 9V battery.

It tastes better than it sounds, believe me.

You can download the STL’s and Arduino code here at Thingiverse.

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Socket to me.

June 6, 2012

I can’t think of many designs that aren’t improved by making them glow. LED’s are the tinker’s equivalent of Photoshop Layer Effects.

The LED socket is my attempt to play industrial designer; I wanted to make an object that was intuitive, elegant, and easy to use. So I started small.

It’s designed to hold a 5mm LED and battery without trimming the leads.

The recessed cradle for the LED is straight on one side so the user is guaranteed to get the orientation of the cathode correct. The grooves on the sides should just fit 5mm LED leads if they’re bent with two 90° angles around the bottom of the socket.

The bottom of the socket is also grooved so that the socket can stand on its base like a candle.

Instructions: Feed the leads through the holes at the top of the socket. Insert the battery through the hole at the bottom of the socket. If the bulb doesn’t light, flip the battery around.

Once the bulb is lit, bend the LED leads around the bottom of the socket and press them into the side grooves to keep them out of the way.

This uses a DL1025 or equivalent battery.