Category Archives: EMSL Projects

Micro Servo Earrings

These earrings — Perfect for radio control and robotics enthusiasts — are made from little servo motors, partially hollowed out for lighter yet weight.


We begin with a “9 gram” class micro servo motors. This is a standard type of servo motor; the same kind that we use to lift the pen or brush on the EggBot and WaterColorBot.

Inside of one of these you’ll find the actual DC motor itself, a set of plastic gears, a potentiometer (pot) connected to the output shaft, and a little circuit board that controls it all. The gear train is used to convert the high-speed low-torque output of the motor into its high-torque low-speed output, and the pot reads the orientation of the output shaft so that it can be controlled (servoed) to the correct position. However for today, we’re primarily interested in the case, and most of what’s inside doesn’t really matter.


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The lower part of the case comes off with four very skinny, very long screws.

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And then, you can pull out the tiny little circuit board.


The DC motor slips out easily, but the three wires to the pot are soldered in, and need to be clipped.

Incidentally, it’s straightforward to hack servo motors, repurposing the circuit board such that (1) the two outputs to the DC servo motor actually control something else and (2) that the input signal from the pot comes from something else. You can read our article about how to make a one-ton servo motor for a good example.



And then there is the matter of the cable. We don’t actually need that much cord hanging out the end — and it weighs something — so we can clip it shorter.


servo-10 servo-11

A dab of hot glue secures the cut-off end of the cable to the bottom of the case.



And the finishing touches: Reassemble the case, add the servo horns and finally the earwires. The final weight of each one is about 6.5 g, and the total weight of the components that we removed (motor, wires, circuit board, and cables) is about 5.6 g. As we have left it, the output shaft feels solidly held in place. Turning the output shaft still turns the gear train, and its motion is limited to the servo motor’s original range of travel; about 2/3 of a turn.

You can make it even lighter — all the way down to 5.4 g per piece — by opening it up further and removing the pot and all of the plastic gears except for the output shaft. It looks mostly the same from the outside (with the exception that the gears are no longer visible), but does not feel nearly as nice: The output shaft is only loosely held on its axis, and now able to turn freely through a full circle.

One might imagine taking it the opposite direction too: Building in a little battery and microcontroller, so that the servo motor would turn on its own while dangling from an ear. That version is left as an exercise for the reader, hopefully one with short hair that won’t get tangled.


If you liked this article, you might like some of our other related projects: Fimo fractal earrings, Chip earrings, Hard drive earrings, and Bobbin earrings.


From the archives: Sweet or Savory Specimen Jars

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From the archives comes one of our favorite food projects: Halloween Cuisine: Sweet or Savory Specimen Jars.

 What good is a specimen jar if you can’t serve it at dinner? The contents of the jars should be genuinely edible, made out of real food. Plastic snakes and spiders are right out.

More Halloween edibles can be found  in the food category of our Halloween Project Archive.

Halloween Project Archives

Array of Halloween Projects

Halloween is one of our favorite holidays, and our collection of Halloween projects continues to grow. Every fall we update it to include our latest projects for the season. In the list … we’ve organized dozens of our Halloween projects into categories: costumespumpkinsdecor and food.

Head over to the Halloween Project Archives for the full list of projects.

Psychedelic Flame Soldering Kit

Last year, we released our Flickery Flame Soldering Kits with six candle-flicker LEDs in red and yellow or white and warm white, to give a fun and semi-realistic flame effect. Now we’re releasing a new Psychedelic Flame Soldering Kit with six blinky-fading-flashy RGB LEDs.

Together the auto-changing LEDs make this a bright, colorful, and kinetic light show. Perfect for holiday decorations (psychedelic Jack O’Lanterns, anyone?), luminarias, scale models, stage props, and parties.

Kit contents

These kits are fun, low-cost, self-contained, and easy soldering kits, which will be right at home both as stocking stuffers and as bite-size first projects for soldering workshops.

Maker Faires and the BIYSL

The Annotated Build It Yourself Science Laboratory

This month I’ll be traveling to Maker Faires in Portland, Oregon, and New York City to sign and talk about my book, The Annotated Build It Yourself Science Laboratory. That, of course, is the new, updated version of Build-It-Yourself Science Laboratory, the classic 1960’s hands-on science book by Raymond E. Barrett.

The Portland Mini Maker Faire is being held September 12-13 at OMSI, the Oregon Museum of Science and Industry. I’ll be speaking on the Innovation stage at 11 AM on September 12. This is a bit of a homecoming for the book: Raymond Barrett was the Education Director at OMSI when he originally wrote the book.

The World Maker Faire is September 26 and 27 at the New York Hall of Science in Queens, New York. I’ll be speaking on the DIY stage on both days.

Bonus: During O’Reilly’s Back to School sale (through September 17), you can get the E-book version of The Annotated Build It Yourself Science Laboratory for 50% off using discount code B2S5.