Build a Robot That Hides When He Gets Shy

Robot Rodney the Red Monster

By Ezra Velazquez

Rodney the Red Monster Robot 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.

Red MonsterRodney the red monster

Parts list:
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 8Ω
2 220µF capacitor
1 100µF capacitor
1 10 µF capacitor
1 1K resistor
2 470Ω resistor
2 10Ω resistor
1 10K potentiometer
1 Red LED
1 Green LED

How the Robot Works

A proximity sensor, built onto the base of the robot, checks for objects within a predetermined range every one 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 and 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.

Testing the Electronic Components

The Construction of Red

The skeleton of Red is made of 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 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 are 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.


• ITP Physical Computing Tutorials
Audio-Sound Module Datasheet
LM386 Audio Amplifier


Breadboard DiagramBreadboard Diagram

Schematic DiagramSchematic Diagram

Ezra Velazquez lives in Massachusetts and is a software engineer at Next Jump. He has a master's degree in Interactive Telecommunications from New York University.

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