1. Improved Robotic Arm and Turntable for Sensitivity Characterization of Occupancy Sensors
Turntable Team
Robotic Arm Team
Sam Garza
Anne Killough
Bob Ramenofsky
Havan Tucker
Will Hedgecock
Brian Auerbach
John Sullivan

2. Sponsor Information Square D produces wall switch occupancy sensors
Senses when room is occupied and switches light on/off correspondingly
Uses ultrasonic and PIR sensing technology
Saves energy by minimizing unused light
Detects major motion in rooms up to 1000 sq. ft.

3. Project Description Improve current testing procedure
Currently takes a minimum of 7 hours to test one sensor
Testing requires 1000 sq. ft. room
Arm does not radiate with IR spectrum similar to that of a human arm
Automate testing procedures to minimize user intervention
Emit IR spectrum similar to that of human arm
Provide more stable arm
Less “jitter” when starting/stopping
Can be held in any position for over an hour

4. Current Testing Procedure
Simulate the testing
room by rotating the sensor and setting the robotic arm at various locations in the coverage pattern. (Measurements in feet)

5. Operational Concept

6. System Design Requirements
Turntable
Sensor mounted exactly 48” above floor
Sensor capable of ± 90 ° rotation at a resolution of .5 of a degree
Portable and Durable
Robotic Arm
Arm must be 18” long with 15” heated
Must be mounted 36” above the ground
Must be heated between degrees Fahrenheit
Peak wavelength emitted 9.4um with a range of 7-15um
Must move 180 degrees horizontal and vertically, but not simultaneously
Must move through 90 degrees of an arc per second

7. Command and Control Interface
Turntable Controls
Robotic Arm
Controls
Automated Testing Grid

8. Control Protocol Robotic Arm Protocol: ASCII Character Decimal Value
Hexadecimal Value
Vertical Up U 85 55
Vertical Down D 68 44
Horizontal Right R 82 52
Horizontal Left L 76 4C
New Speed S 83 53
Turntable Protocol:
ASCII Packet
Rotate R
Sensor On ON
Sensor Off
OFF
Acknowledgement
ACK

9. Functional Flowchart

10. Microcontroller Overview
NetBurner MOD5272 Development Kit:
Motorola MFC5272 Microcontroller
NetBurner MOD5272 Development Board
NetBurner Embedded Ethernet Core Module
2 Serial Ports
4 Timers
General Purpose I/O Ports
(50 pins per header)
32-bit processor

11. Robotic Arm Assembly Overview

12. Robotic Arm Operational Flowchart

13. Robotic Arm Firmware Initializes microcontroller’s IP address via DHCP
Sets up a listening socket on port 24321
Accepts an incoming TCP connection from the Command and Control Assembly
Receives control packets from the Command and Control Assembly
If microcontroller receives an ‘S’ packet, it parses the integer value in rest of packet and sets the speed of motion of the arm to traverse this integer number of degrees per second
If microcontroller receives a ‘U’ or ‘R’ packet (Up or Right), the direction pin is set to high, else low

14. Robotic Arm Firmware (continued)
Controls robotic arm motion via pulses from two GIOP pins on the microcontroller
Stepper motors require 500 steps to rotate 90° of an arc and stepper controllers cause motors to step once on every falling edge of a pulse from the microcontroller
Using the internal timing system of the microcontroller, interrupts are generated every 1/500th of a second
If motion is desired, every interrupt sends a pulse to the stepper controller until 500 steps have been made

15. Infrared Background Information

16. Thermal Element Specifics
4 Silicone Rubber Heaters
4 Solid State Relays
1 OMEGA 1504 Multiloop PID
1 120VAC Variable Transformer
1 Roll of Electrical Tape

17. Thermal Proof of Concept

18. Mechanical Design Problems
Last Year’s Design Problems:
Arm diameter below NEMA requirements
Arm length below NEMA requirements
Low Torque
Constant Shaking
Solution:
Direct Drive Stepper
Motors
Open Loop System
Arm to correct specs

19. Turntable Assembly Overview

20. Turntable Firmware Responsibilities
Maintain communications with the computer
Control the servo motor
Keep track of the status of the relay
Maintaining Communications with the Computer
Using DHCP to automatically assign an IP address
Initializes the TCP/IP stack
Listen for TCP connections on and 24322
Wait until connections are established
Pass control to the main OS task

21. Turntable Firmware (continued)
Control the Servo Motor
Using the timer system to scale down the clock
Output compare to match our timeout values
First a timeout value is set for the high part of the square wave
After this timeout, a value is set for the low portion of the square wave
This creates a 33 ms period of variable duty cycle
Keep Track of the Status of the Relay
Utilizes the same timer system that controls the servo motor
When the relay state changes, sends a TCP message to the controlling computer

22. Turntable Hardware Motor Sensor Mount Cart Hitec HS645MG servo motor
107 oz-in. of torque at 4.8 V
Dual ball bearing design
Weighs 1.94 oz.
Sensor Mount
Indoor single gang box
PVC construction
Cart
Buhl BAV-4226C compact AV cabinet cart
42’’ tall

23. Results
All requirements met! See final assembly for physical results of project.