Lab 6 :: Mobile

Submitted by ajeeta on Tue, 03/12/2013 - 22:55
ajeeta's picture


I tried making a simple mobile for this project. The spin of the motor seemed weak, so I wanted to make something with as little weight as possible.

To begin with, I experimented with different sizes and weights (CD, thin paper, thicker paper card; big and small) for the top disk that would sit on the motor. The CD was too big and heavy, slowing down the spin. The paper sheet was too flimsy. The smaller and thicker paper card (seen in the attached images) was the fastest and most stable on the motor, and worked the best.

To keep the weight low, I used post-it cut-outs for the mobile shapes.

Next, I used toothpicks to suspend the mobile shapes. However, the toothpicks added weight slowing down the spin.

So I substituted the toothpicks with thread. However, while spinning, the thread got tangled around the wires  (in part due to the manner in which the motor needed to be held in one hand, with the wires sticking out at the bottom). Also, the long thread attachments slowed the motor down. The next step was to cut short the threads. Shortening helped the speed, but the threads were still getting tangled around the wires

Eventually, I just had a spinning disc, captured in this video.

Before I could experiment more and have a better working prototype, one of the motor wires broke off.



Arduino Uno


DC Motor

1k Resistor



External Battery

Wires and Cable


For Mobile:

Paper Card

Post-Its for Mobile Shapes





(Unchanged Stock Code from Class)


 * one pot fades one motor
 * modified version of AnalogInput
 * by DojoDave <>
 * Modified again by dave
int potPin = 0;   // select the input pin for the potentiometer
int motorPin = 9; // select the pin for the Motor
int val = 0;      // variable to store the value coming from the sensor
void setup() {
void loop() {
  val = analogRead(potPin);    // read the value from the sensor, between 0 - 1024
  analogWrite(motorPin, val/4); // analogWrite can be between 0-255
Using a Thread instead of Toothpicks
Mobile Shapes
Toothpicks for Attaching Mobile Shapes
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