Light Dependent Robotic Bugs

This time I share with you an easy STEM project to teach the kids how a LDR works together with a transistor to build a robotic bug with light dependent motion.

I hope you like it.

List of Materials

Battery holder with switch (2 x 3V Lithium Coin Batteries, 2032)
Two red leds
One vibration motor
One 2N2222 transistor
One LDR
Wire

Print the Plastic Base

The piece is formed by two parts: the main base and one little plastic cylinder where to glue the pieces to convert it in the bug you want

Downloads

Bug Base.stl

Place the Leds and the LDR in the Base

Insert the leds and the LDR in the position you see in the image. After that fix both components with silicone.

Place the Transistor

Place the transistor as you can see in the image. Please pay attention to the position of the transistor to solder all the components.

Place the Battery Holder on the Base

Make two little holes near the holder to pass trough the positive and negative wires

Solder All the Components

The steps are the following:

Solder the cathodes (-) of the leds
Solder the anodes (+) of the leds
Solder the Vcc of the battery to the emitter terminal of the transistor
Solder the Vcc cable of the vibrator motor to the colector of the transistor
Solder the anodes of the leds to the colector terminal of the transistor
Solder one of the LDR terminal to the base terminal of the transistor
Solder the other LDR terminal to Vcc of the battery
Solder the Ground cable of the vibrator motor to the Ground of the battery
Solder the cathodes of the leds to the Ground terminal of the battery

Place the Legs

Make two little holes to pass trough the wire for the hind legs.
The third leg is the base terminal of the transistor.

Let Fly Your Creativity