Lynbrook HS RoboticsSan Jose, CA

aMazing RobotiARoC Presentation

Hardware

Sharp IR Sensors• Uses IR waves to figure

out distance from an object, such as a wall. (We use 4)

• One side emit's light, and the other one detects it, and converts to voltage. Our software converts to distance.

Sharp IR Sensors (cont.)

• 2 Models: GP2D12 range = 10-80 cm and GP2D120 range = 4-30 cm

• Mounted on L-Brackets on robot

Maze Construction

• Used Styrofoam walls which were cut by a hot wire cutter.

Software

Custom PCB Board

• Facilitates connection of analog input devices to SunSPOT.

• pulls 18V from iRobot Create for power, reduces to 5V through regulator.

Simulator• Completely transparent:– Robot runs the same on

simulator as it would in physical world

– Implemented actual and simulated versions of all SPOT/Create functions (sensor data, driving, turning, storage etc)

• Used to test algorithms for exploring/saving map/finding the fastest path

Doing the Math

• Finding the relationship between sensor voltage and distance (cm)

• Lots of Trigonometry for the robot’s movement and heading!

Algorithm

• Explore by hugging the right wall (until robot ends up where it started), then by hugging the left wall

• Guaranteed to explore the entire map• Store data in 12x4 array (12x7 because you

don’t know where you start)• After exploration, robot will figure out the

fastest path based on collected data

Reliable Driving

• We want to keep our movement from cell to cell.

• Detected for a transition from “wall” to “no wall” on right side and recalculated the distance to move into the next cell.

• Used front sensor to maintain space from walls in front.

Squaring Up

• Since the robot would accumulate an error in its heading, we had to fix the angle.

• Using 2 sensors in the front we can calculate the difference and pivot until the robot is square to a reference wall in front.

• In order to square up, the robot has to move into a “sweet spot” for the sensors.

• Afterwards, the robot backs up to center itself in the cell.

Lynbrook Robotics iARoC Team

• David Giandomenico – Coach• Daiwei Li• Johnathan Chai• Aashish Sreedharan• Michael Wachenschwanz• Matt Hong• David Liu• Toshitaka Tachibana• Abhinav Sinha• Jaya Sreedharan - Parent