Assignment 3: Fetch Bot

The aim of this project was to build a light following robot that would eventually have the ability to "fetch" an object and bring it back to the owner based on the light sources.

Part 1a: design and setup (hardware)

Components:

• 2 x continuous rotation servo motors

• 3 x photoresistors

• 3 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

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Design:

The design basically has everything LED on one side of the breadboard and everything Photoresistor on the other. I seperated the two halves with a credit card and my one card to ensure that the light from the LEDs would not throw off my photoresistor readings too badly.

I used the basic setup for photoBot (shown below) with the additional adjustment of placing a photoresistor in the center (not shown in the diagram below).

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Part 1b: design (software)

The thought process behind the logic for the movements:

• Stop if all photoresistors are receiving the same amount of light.

• Forward if light is brighter in the center than in the left and right.

• Backwards if the left and right photoresistors are receiving the same amount of light, and this amount is greater than the amount reaching the center photoresistor.

• Right turn if there is more light reaching the right photoresistor than the center photoresistor, which in turn receives more light than the left photoresistor.

• Left turn if there is more light reaching the left photoresistor than the center photoresistor, which in turn receives more light than the right photoresistor.

• Move NorthEast if the center photoresistor and the right photoresistor are receiving the same amount of light, which is greater than the amount of light reaching the left photoresistor.

• Move NorthWest if the center photoresistor and the left photoresistor are receiving the same amount of light, which is greater than the amount of light reaching the right photoresistor.

• Move SouthEast if the right photoresistor gets more light than the center photoresistor, which is receiving the same amount of light as the left photoresistor.

• Move SouthWest if the left photoresistor gets more light than the center photoresistor, which is receiving the same amount of light as the left photoresistor.

Part 2: implementation to determine light status

Video Demonstrating the LEDs:

Part 3: implementation of new movement functions

Video Demonstrating the Movements:

Part 4: putting it all together

What I think is the best take:

Alternative take:

I have additional takes of individual portions of movements working correctly. Please ask if you want to see these. I chose not to include them because I thought it would make the post too long!

Additional Thoughts

• Problems:

• In a given room, the light is different, so calibrating the sensors was difficult. This made testing hard as well.

• Hardware did not always run how it was supposed to.

• Backwards motion was difficult because the photosensors were so close together, therefore my logic sometimes did not hold.

• Bonding Experience!

• Picture of Claire and I coding late at night!

• Video of Yada dancing during our robotics break!

#assignment