Introduction: Useless Machine: El Rompe Huevos

About: Architect, Wearables explorer, Techie.

Say Hi to El Rompe Huevos, the useless machine created by Jorge Christie and Rebeca Duque Estrada

What should it do?

It’s brunch time and you are dreaming to have your soft eggs. As breaking the eggs needs a lot of attention and experience, we developed a robot to help you! But… something went bad during it’s birthday and it came to the world a bit rebel. It will really try to help you, but if you put some nice song to play during your brunch, it can get really excited and things can go wrong..

So, enjoy your brunch and hope it can mess some things around =)

Step 1: List of Parts

This is the list of parts you will need. The 3D printed support you can make the way you prefer, but always remember to let enough space for the electronics.

1x Servo Motor SG90 [1]

1x Limit Switch [2]

1x Microphone-sensor Module Iduino SE019 [3]

3x Red LEDs [5]

1x Arduino Uno [4]

1x Protoboard [6]

1x nice 3D printed support

1x spoon of your preference

1x Battery module (optional)

A bunch of cables [7]

Some eggs

Step 2: The Support

The 3D printed support was designed considering a place for the egg with a small aperture to fit the button, the support for the servo to turn the spoon, a place for the Arduino and electronics inside to be protected from the mess that can happen. And some lights that will blink with the music.

Step 3: Code

The code works with two inputs: The button and the microphone module. The button, placed beneath the egg, senses when the egg is in place and through a “if” condition it starts running the code. The microphone starts to read the sound in the environment and when it fits in the specified range, it triggers the two outputs: the servo that rotates the spoon and the LEDs that starts shining with the rhythm of the music.

Some mapping and “if” conditions were used in other to avoid noise.

To start wiring your components, just take a look at the fritzing diagram.

// Useless Robots Presents:
// ElRompeHuevos // Code by: Rebeca Duque Estrada and Jorge Christie

// Code for Motor and sound integration based on: // // Make a Servo Move to Sound. // // 2012 by Cenk Özdemir

//Servo #include // creating a servo object Servo myservo;


int sensorPin = A0;

int sensorValue = 0; //Button

int buttonPin = 2;

int buttonState = 0; //LED

int ledPin = 12;

void setup() {




pinMode(sensorPin, INPUT);

pinMode(buttonPin, INPUT);

pinMode(ledPin, OUTPUT);


void loop() {

buttonState = digitalRead(buttonPin);

if (buttonState == LOW) // It's working in the opposite way. LOW when the button is pressed. If the condition is true, start the whole magic and let's break some eggs ;)


int sensorValue = analogRead(sensorPin);

int LEDValue = map(sensorValue, 0, 150, 0, 255); // Map a value for LED that can be an integer between 0..255

sensorValue = map(sensorValue, 60, 150, 80, 45); // Map the possible range of servo with the sensor values. int MoveDelayValue = map(sensorValue, 0, 300, 0, sensorValue); // set the servo into standard position Serial.println(sensorValue);

if (sensorValue < 80) { // cut some noise with a if condition


myservo.write(sensorValue); // move the servo to the mapped reading

analogWrite(ledPin, sensorValue); // turn led on with the calculated value

delay(MoveDelayValue / 2); // and move in this delay time


analogWrite(ledPin, 0); // turn off the led again.


else {

digitalRead(sensorValue == 0);



Step 4: Assembly - 1

First: assemble all your circuit and test that it’s working as expected. Tag them and disconnect to proceed with the assembly.

Step 5: Assembly - 2

The light bulbs were extended with a pair of wires. Install all the lights in the holes. Add hot glue for fixing them

Step 6: Assembly - 3

Install the servo and fix it with hot glue.

Ideally, tag your cables prior to the installation so it’s easier to re-plug all.

Step 7: Assembly -4

Extend the connectors of the microphone so you have more flexibility for placing it.

Place it in the support and glue it

Step 8: Assembly - 5

Place the button board in the slot and fix it with glue.

Put the cap and verify that the button can be activated by the egg.

Step 9: Enjoy Your Brunch and Have Some Fun =)

Now it's time to try your own Rompe Huevos.

Put an egg on the support and play or sing some music to activate your useless machine.

Be ready to clean some mess afterwards.

Step 10: