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17. Machine design

Monkapolt/guillotine monkey

See our groups documenter Daniel for the complete documentation. The servo arm powered monkey was a good first round prototyping exorcize however my subsystems task in the machine changed. The new function is to launch a ball that reaches the next subsystem that triggers a reaction to the next. I was looking at different catapult mechanisms for this. I still wanted to run with the monkey idea, so why not a “Monkapult.” This mechanism essentially works as a spring loaded hinge. The monkeys arms are on a hinge loaded by rubber bands. My design features a motion sensor that detects the ball rolling past down the ramp and for that to trigger the guillotine monkey to begin chopping the rubber band.

I started by designing a solenoid board with a distance sensor.

See week 12 for more information.

Next I compiled a program that executes the solenoid to fire when the distance sensor is triggered.

 #include <SoftwareSerial.h>
  const int trigPin = 9;
  const int echoPin = 8;
  const int RX = 1;
  const int TX = 0;
  const int solenoidPin = 3;    
  const int trigger = 10;
SoftwareSerial Serial (TX, RX);
  float distance, duration;

void setup () {
  pinMode (trigPin, OUTPUT);
  pinMode (echoPin, INPUT);
  Serial.begin (9600);
  pinMode(solenoidPin, OUTPUT);           //Sets the pin as an output
  //Serial.println ("Initializing");

void loop() {
  digitalWrite(trigPin, LOW);   
  digitalWrite(trigPin, HIGH);
  duration = pulseIn(echoPin, HIGH);
  distance = duration * 0.034 / 2;
  delay(10); // for data to be read correctly by processing.

  if (distance < trigger) {

  digitalWrite(solenoidPin, HIGH);    //Switch Solenoid ON
  delay(10);                      //Wait 1 Second
  digitalWrite(solenoidPin, LOW);     //Switch Solenoid OFF


Part of this assignment is to have a “packaged” machine so I wanted to hide the solenoid. My classmate JT and I came up with a monkey seat design that hides the solenoid perfectly and provides the monkey with a comfortbale seat.

In addition to the “monapolt” I designed and produced t-shirts for our group. The picture below features one of our wonderful instructors Greg Buckland

Design Files







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