Making Things Interactive

February 19, 2008

Rotational Forms

Filed under: 6: More Motion,Assignments,Nadeem Haidary — nhaidary @ 2:09 pm

I’m using the potentiometer to control a DC motor. I made this as a tool to experiment with rotational forms. You can put a profile on the disc and the motor will spin it to give the illusion of a 3-dimensional form. I was looking at how fast the disc needs to be spinning to create the illusion. I was trying to see how fast the disc needs to be moving for an LED to look stable even though it is actually only seen once per revolution (through the hole).

I am having problems with the power to the motor dying periodically if I crank it up high. I reverted to thick paper after experimenting with foamcore-but the motor is not powerful enough to spin it quickly.

by Nadeem Haidary

with help from ITP Physical Computing tutorials

int transistorPin = 9;              // connected to the base of the transistor
int transistorValue = 180;          // initial value for motor speed (through transistor)

int potentiometerValue = 0;         // the value returned from the potentiometer
int potentiometerPin = 0;           // the analog pin reading the potentiometer
int motorSpeed = 0;


void setup() {
pinMode(transistorPin, OUTPUT);   // Set transistor pin as an output pin


void loop() {

//-----DC MOTOR-----
potentiometerValue = analogRead(potentiometerPin);     // read the analog input
motorSpeed = potentiometerValue/4;                     // converts the potentiometer value (0-1023)
// to a range between 0 - 255 for the motor
transistorValue = motorSpeed;                           // Transfer windspeed to motor
analogWrite(9, transistorValue);                       // Turn the DC motor on



1 Comment »

  1. If you’re powering the motor off of the Arduino, you’re probably reaching the limits of the current that the Arduino can supply. An external battery pack will probably give the motor plenty of power.

    Comment by jet — February 20, 2008 @ 3:37 pm | Reply

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