How to Make a Solar Robot!

About: I'm a student of mechanical engineering at Aalborg university in Denmark. I absolutely love to tinker with electronics and mechanics, and thus much of my spare time is spent on hobby robotics and 3D printers...

This is how to make a trimet.

The parts you need are: 3 Capacitors, a 2N3904, a 2N3906, a resistor(1k to 10k ohm), a solar cell (minimum 3 volts), a dc motor(the flatter the better).
you'll also need a blinking/flashing LED (FLED).
to help you, i have made a, very easy to follow, schematic of the circuit
, which can be found on



  • Pocket Sized Contest

    Pocket Sized Contest
  • Remix Contest

    Remix Contest
  • Tape Contest

    Tape Contest

7 Discussions

peterjacobGhost Wolf

Reply 7 years ago on Introduction

You can find them in all solar-powered devices(garden lights, many calculators etc.) and you can easily buy them on the internet, which is what i did.

peterjacobGhost Wolf

Reply 7 years ago on Introduction

I had same problem. This means your capacitors discharges too frequent. you should try changing the resistor with one with more ohms or with less. the resistor determines how much power are stored on the capacitors before they are used for the motor.
it could also be because your robot is too heavy for your motor to move, or your motor is a weak one. if you can find any flat motors you should use them. Flat motors generally have more torque.

resistors and flat motors can be found in game-controllers, like the joystick from a play-station (what i used because i have a few old ones laying around)


7 years ago on Introduction

thanks a lot for your video, it really very helpful video.

would you share principle of circuit?