Let's Make Robots!

Rocket Brand Studios Tadpole Spurt Light Follower

Rolls into the light


Well, Chris the Carpenter has been hard at work since MakerFaire perfecting a design for a robot kit that can do... anything. Well, almost anything. OK, a lot of things. Cool things that we usually ask basic robots to do. He calls it the Tadpole, and it is very neat.

I'm working with Chris to create some designs that operate without a microcontroller, Inspired by the SpurtBot designs from Rostock University and my own work in this area.

Here's the second SpurtBot based on the Tadpole Educational model, with the Spurt add-on to the chassis to allow the solderless breadboard to be extended in front of the robot and inverted so sensors can point to the floor. You can easily flip the robot over to work on the circuit.

I've posted some assembly instructions on Instructables.


Above: Acutal Breadboard


Above: Fritzing Breadboard Layout


Here's the schematic for the circuit.

(click for larger image)

Note that the Light Dependent Resistor (LDR) on the right side of the robot is connected to the motor on the left, and vice-versa. This is so that when one of the LDRs detects light, it turns on the opposite wheel, turning the robot towards the light.

Component List:

  • (2) BC337 NPN transistor
  • (2) Light Dependent Resistors (LDRs) (Jameco Part #202403, 200k Ohm in dark)
  • (2) 2-pin male-male headers for connecting motor leads to breadboard
  • (2) 1-pin male-male headers for connecting power and ground
  • Some solid core hook up wire for making connections on the breadboard


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