1. By Vivek Manoharan TAs: William Dubel and Steven Pickles
Ball Man – Sensor Oral
By Vivek Manoharan
TAs: William Dubel
and Steven Pickles

2. Bump Switch Basic use for an ENTER KEY
Helps with initializing Ball Man under different conditions
LCD feedback initiates use of ENTER KEY

3. Photocell Resistor Indicates lighting conditions
Helpful for differentiating between need for white balance and not

4. Ultrasound Sensors – SRF-04
Once one sensor is able to ping the tennis ball, respective DC motor will “slow down” to allow robot to turn
Then, when ping rates are equal, DC motors will run at same speed straight ahead
Experiments

5. Distance Accuracy Sample table, one SRF-04
Used maximum pre-scaling (1024)
148us = 1in 2
3.0900”
3.0” 3
5.1150”
5.0” 4 ”
10.0” 5 ”
15.0” 6 ”
20.0”

6. Difference Tests Dual SRF-04 setup
Measured offset needed for BallMan to understand “equal” distances 5
0.375” 6
0.563” 7
0.438” 8 9 10
0.625”

7. CMU Camera Detect contrast level of tennis ball on tennis court
Green – Pickup tennis ball
Bright Red – Home Base
Test range of contrast detection

8. White Balance Indoors
White Balance off

9. White Balance Indoors
White balance on

10. Conclusion Further tests for CMU need to be run outdoors
White balance is crucial for contrasts
Ultrasound ranges are not as far as claimed (distances become iffy after 90”)