Basic Motorised Timelapse Camera Colly, Based on Lego Train

I wanted a dolly to record a timelapse movie with an automatically controlled motor for my iphone gorillapod, so I took the legotrain from my kids, measured the input voltage, added an arduino and mosfet and programmed the train to move one millimiter every five seconds.

Step 1: Hacking the Legotrainconnector

I measured the voltage for the trainmotor, it works from 3-6v. Perfect for the 5v output of the arduino.

Use the topside, so if you want to give it back to your kids, you can easily remove the wires and rebuild it.

Step 2: Wireing the Arduino

It is possible to use an h-bridge to make the train go in two directions, but I was merely intrested in a quick sollutions, so ...

I used a tip120 mosfet (I guess this is ampère overkill, but anyway), connected as base via a 1K resistor to arduino port 2.
A led (+220Ohm) as control-light. (you can skip it)
5v from the arduino to the train and the gnd of the train via the collector pin of the mosfet.
Finally the emitter side connected to the gnd of the arduino.

Step 3: Arduino Code

Super easy.

#define motorPort 2

void setup() {
  pinMode(motorPort, OUTPUT);
}

void loop() {
  digitalWrite(motorPort, HIGH);
  delay(20); // giving just enough power to move 1mm)
  digitalWrite(motorPort, LOW);
  delay(5000); // wait 5 seconds
}