Meet Rodney, the (shy) red monster

Rodney the Red Monster

December 14th, 2010 in Electronics by 1 Comment

Rodney the Red Monster is a little shy of humans, the weirdest creatures in the known universe.


In the depths of Southern New Jersey there lives the mythical Jersey Devil, a monster so fierce and revered that no one dares travel to its swamps. I was ready to find the worst, and instead found Rodney.

This is his story.

How It Works

A proximity sensor, built onto the base of the robot, checks for objects within a predetermined range every 1 second. If an object enters the sensor’s range, the neck of the robot collapses into its body. This action is achieved by choreographing the movement of the base & middle servos, which act as the robot’s neck joints. Once the object leaves the sensor’s range, the robot “pops” its head back out by powering the two neck servos.

The top servo motor, which is the smallest of the three, moves the eyes of the robot back and forth when the neck is fully¬†elongated. The servo motor moves the eyes back to their original position when an object enters the sensor’s range.

The sound module plays audio clips while an object is outside the sensor’s range. When an object gets within range, the audio track stops.



  • The skeleton of Red Red is made of (3) three scrap pieces of wood found at the ITP shop.
  • The neck is made of thin aluminum sheet strips.
  • The body cavity is made of (2) two oatmeal barrels.
  • The fur is made of “fancy” red yarn (that’s what the store calls it, I like it because it feels, well, furry).
  • The extremities is made of styrofoam and tube cleaners.


  • The LEDs are used as status lights.
  • Green LED lights up when the audio-module is playing files.
  • Red LED gets brighter as an object gets closer to the proximity sensor.
  • The potentiometer is used to set the signal strength from the audio module to the ¬†LM386N chip.

List of parts (Bill of Materials):

  • (1) Arduino
  • (1) LM386
  • (1) Audio-Sound Moule – SOMO-14D
  • (1) Infrared Proximity Sensor Long Range – Sharp GP2Y0A02YK0F
  • (2) Servo – Large Full Roation
  • (1) Servo – Small
  • (3) TIP120
  • (1) LD33CV
  • (1) Speaker – 0.5W 8ohm
  • (2) 220 uF capacitor
  • (1) 100 uF capacitor
  • (1) 10 uF capacitor
  • (1) 1K resistor
  • (2) 470 ohm resistor
  • (2) 10 ohm resistor
  • (1) 10K potentiometer
  • (1) Red LED
  • (1) Green LED




Easter Egg:

Author: ezraezra

I see you looking...

One Comment

Hey man, awesome, I love this. Is there a video of it in action?



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