PhotoBot

In this part of the lab, you'll adapt your BasicBot and code from Assignment 1 to build a PhotoBot that will turn to wherever there is more light. If you would rather work from solutions, download them from moodle.

Components

Electronics and microcontroller

- 2 x continuous rotation servo motors
- 2 x photoresistors
- 2 x 10k ohm resistors
- 3 x LEDs (pick the same color)
- 1 x 200 ohm resistor
- 1 x Arduino Uno
- 1 x breadboard
- jumper wires

Power supply and shell

- 1 x battery holder for 6 AA
- 6 x AA batteries (rechargeable is fine)
- 1 x snap attachment to DC power plug
- 1 x robot base (e.g., plate or vinyl record)
- 2 x wheels compatible with servo motor (e.g., thingiverse part)
- 2 x wheel treads (e.g., o-ring gaskets)
- 1 x stabilizer caster wheel

Tools

- small philips head screwdriver
- glue gun

Setup

Set up your project, but do not attach the USB cable.

Adapt your sketch

Adapt the sketch from Assignment 1 by adding in code from your BasicBot to:

declare 2 variables of type Servo
1. 1. leftServo

1. rightServo
2. declare 2 variables of type int for your stop values of each servo
3. leftServoStopValue
4. rightServoStopValue
5. declare 2 variables of type int for the pins to control your servos
  1. leftServoPin (assign this the value 9)
  2. rightServoPin (assign this the value 6)

declare and define four methods:

1. initServos should initialize both Servo objects
2. rotateLeft should rotate the bot left (counter clockwise)
  1. rotateRight should rotate the bot right (clockwise)
  2. stopMoving should stop moving the bot
3. modify your setup to invoke initServos

Additionally:

1. declare and define a new method rotateBot to
  1. rotate the bot left if there is more light sensed on the left; or
  2. rotate the bot right if there is more light sensed on the right; or
  3. stop the bot if there is the same light on both sides
2. modify your loop to invoke rotateBot after invoking updateOutput

Test it out!

Being careful to manage your power supply, test out your code. Your bot should rotate according to the light. If it's brighter on the left, the bot should rotate left; on the right, and the bot should rotate right.

Submission

Upload your photoBot sketch to moodle's Lab 2 - servo motors.

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