Lab 1: Microcontroller

Overview

The purpose of Lab 1 was to make us accustomed to some basic functionalities of Arduino Uno and the Arduino IDE, such as assigning analog and digital outputs, and driving peripheral devices (LED, Servos, etc). The ultimate goal of the lab was to create an assembled robot that drives autonomously.

The overall procedure of this lab can be summarized into following steps:

Blink the onboard hardwired LED using the Blink sketch
Modify the sketch so it can light up an external LED in series with a 330 Ohm resistor
Read the Analog input from the potentiometer, and print the voltage values on the serial monitor
Use the Potentiometer to control the brightness of the external LED
Test Drive a servo motor and calibrate the servo motor
Control the rotation speed of the servo motor using a potentiometer
Assemble a robot and modify the code accordingly

Required Parts:

Team Box (arduino + USB Cable)
2 Continuous rotation servos
1 LED
1 Potentiometer
Several resistors (330 Ohms)
1 solderless breadboard

Other than the required parts listed above, we also had to retrieve the frame and motor mount. These secured the arduino board and mounted the motors, respectively. We also needed a ball-bearing to keep the robot balanced.

Modifying the Blink Sketch

This part of the lab required us to modify the Blink sketch to light up a LED for 1 second, then off for one second (and repeat). We first did this for the onboard LED, and then applied this to an external LED.

Reading a Potentiometer

This part of lab asked us to read the voltage across a potentiometer, and then display these values in the serial monitor.

LED Brightness with Potentiometer Control

We then modified our LED code to read the voltage across a potentiometer, and change the LED brightness based on that voltage. The higher the voltage, the brighter the LED.

Driving a Servo Motor

We connected the Servo motor as follows: the red wire went to 5V output, the black wire went to ground, and the white wire went to the digital pin with PWM capability (in our case, it was digital pin 11). The servo motor started to rotate after the arduino was powered up.

Driving a Servo Motor with Potentiometer Control

We modified the Servo Motor code to change speeds based on the voltage across a potentiometer.

#include "Servo.h"

int Potential = A1;
int num = 0;
float volt = 0;
int motor = 11;
Servo servo;

void setup() {
  Serial.begin(9600);
  pinMode(Potential, INPUT);
  servo.attach(motor);
}

void loop() {
  num = analogRead(Potential);
  volt = num*180.0/1023.0;
  servo.write(volt);
  delay(1000);
}

Assembling the Robot

This part of the lab required us to attach the arduino and battery to the platform, assemble the wheels and ball bearing, and mount the motors.

Assembled Robot

Integrate Arduino Sketch and robot

We tested different servo motor inputs to understand basic controls. These inputs caused the robot to go straight, turn left, turn right, and perform these activities at different speeds.

Robot Autonomous Drive

Our robot’s first autonomous drive included a quick dash forward, a 360 degree turn in place, followed by another dash forward. We were so proud!

The Nines