Wingardium Leviosa - The Floating Feather

by timothy.high

Published on November 4, 2016

Using a tethered DC motor and the Bluetooth LE component, make a feather quill pen, or anything else, magically float into the air and come back down!

The circuit is based on the new Gadgets & Gizmos Kit 2nd Edition, using the Bluetooth LE coponent to let you control via a smartphone whether the feather floats up or down. We attached it to a tethered DC motor, switched to "variable", and then put a big Lego wheel on the end (larger than a "normal" Lego wheel, but smaller than the wheel that comes with the kit). The size of the wheel makes all the difference for how fast the object will rise and fall.

Place the circuit somewhere up high and tie or it down so it doesn't move. Affix some fishing wire or another kind of "invisible" string to the wheel and your object, then connect to the bluetooth piece. Using the Slider control, you can then make your feather rise up and float back down!


How To Make It


Construct the circuit Make a simple circuit: battery to power, power to BLE component, BLE to tethered DC motor. Optionally, mount it all on a mounting board, just to keep it all in one place.


Attach a wheel to the motor Using the DC "foot" attachment and some Legos, attach the wheel to the motor. It doesn't have to be Lego, but that's the easiest. Not that the size of the wheel makes all the difference in the speed that the object will rise and fall. I found the wheel that comes with the kit to be a little too big, but it would actually work perfectly well - just be careful not to turn the slider too high up or down. If you use the kit's wheel, you should create artificial grooves on the edges to keep the string from rolling off the edge of the wheel. You can use cardboard wheels, or tape string to the edges, etc.


Affix the circuit to a nice, high place Tie or tape down your circuit somewhere up high and out of sight, preferably so that only the "invisible" wire shows. Most importantly, you need some way of making sure the string hangs straight down over the place your object is meant to levitate, with enough space on the side so it is't just "crawling up" your furniture. Place it so that the wheel is free to turn both ways without rubbing against anythig. Make sure it's nice an sturdy, or your object might pull your circuit off the dresser, ceiling, etc.


Attach the wire to the wheel Tie or tape the string/wire to your wheel. If you can tie it, great! Otherwise, make sure the tape has a good enough grip on your wire to keep it from yanking out under the weight of your object. The string needs to be able to roll up around your wheel both ways, and should not be able to roll off the edge of the wheel. Finally, tie the string to your feather or object. Choose a string long enough to reach your object, but it should be under just a slight amount of tension at rest to ensure that the object lifts up as soon as the wheel starts turning.


Connect to the BLE to make magic! Switch your DC motor to "variable" mode. Turn on the circuit, but careful! For some reason, in variable mode, the motor starts turning even without a signal. Quickly open the slider control in the littleBits app, connect to the BLE component, and move the slider to center (stopped). Now you're ready! Move the object back down to rest, and call in your friends and family to amaze and delight!

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