I've previously demonstrated how to use littleBits and erector set parts to build a magnetic stirrer and a sample rotator. Since I was able to drive Erector set machines with the littleBits motor I decided to try to use it to drive K’nex contraptions. Currently, littleBits has a Lego cross axle adapter for the littleBits motor, but there is no adapter for K'nex to drive K'nex machines. In this first attempt, I was able to design a hybrid of Erector set parts and K’nex parts to build a K’nex kinetic interactive sculpture I call “Mutually Assured Destruction.”
Step 1: Build the K'nex and Erector Set Hybrid Motor Mount for the LittleBits Motor
I was unable to come up with a simple way to attach the littleBits motor directly to K’nex parts without using, say, a hot glue gun, so I decided to use erector set parts for a non-permanent attachment to K’nex parts. The Erector set motor mount for the littleBits motor can not only be attached to K’nex parts with nuts, bolts, and washers but can also be attached to Lego Technic parts as well as other construction toys or materials.
I put the rectangular plate on the motor axle and used the small hex wrench to mount the Erector set pulley on the axle—I had to use two set screws to center the axle since the littleBits motor axle is smaller than an Erector set axle.
Parts for the motor mount:
Small Erector hex wrench
Large Erector hex wrench
1 plate 2X3
1 right angle plate 3X3
1 large pulley
2 set screws for pulley
2 right angle brackets 1X1
2 small screws
4 medium screws
Silicone sleeves to keep nuts tight (optional)
1 littleBits motor
Construction toys or other material where motor is attached (in this case 2 K'nex 5-way connectors)
Step 2: Build the Clockwork Flower Base and Stem
Next I built a base and a stem for my clockwork flower. Then I added the littleBits motor to the flower stem. I topped the flower stem with the housing for the gears for the clockwork flower. I added the lower axle and the small K’nex gear. I then added the upper axle and the large K’nex gear. I also mounted the belt from the large pulley to the small pulley. The flower petals will be added to the lower axle.
NOTE: You might be able to attach the drive belt directly to the K'nex axle, but because of the way the axle is manufactured, there is a seam in the middle of the axle that might contain sharp edges that could cut through the belt. I added the small Erector set rubber pulley to the end of the axle to save the belt from excessive wear or being cut by the seam.
Step 3: Build the LittleBits Circuit
The littleBits circuit is very simple. It consists of the battery and power module, the light sensor module, and a wire module that's connected to the motor.
To operate the clockwork flower, simply switch on the littleBits power module and move your hand over the littleBits light sensor to slow down or speed up the spinning of the flower petals.
Parts for littleBits circuit:
1 battery and power cable
1 power module
1 light sensor module
1 littleBits wire module
1 motor module (already attached to flower stem)
Step 4: Mutually Assured Destruction Interactive Kinetic Sculpture
Why the title “Mutually Assured Destruction?” It’s a mechanical flower, but the petals are made of K'nex foam missiles and for some reason I thought of the 1967 photograph “Flower Power” where hippies are stuffing flowers down the barrels of M14 rifles pointed at them by National Guardsmen at a Vietnam War protest.(1) The Vietnam War was part of the larger Cold War in which there was a nuclear arms race between the United States and the Soviet Union. Foam missiles > Flower Power > Vietnam > Cold War > Arms Race > MAD (Mutually Assured Destruction). Don’t worry if you’re not following the progression—modern art just happens that way sometimes.
Currently, there is no K'nex adapter for the littleBits motor to drive K'nex contraptions.The simple design of the motor mount out of Erector set pieces for the littleBits motor allows it to be easily attached to K’nex parts to motorize your K’nex machines. The same motor mount can be attached to Lego Technic and other construction toys or materials.
(1) "Flower Power"