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

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.

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

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)

Operational Concept

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

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

Control Protocol ASCII CharacterDecimal ValueHexadecimal Value Vertical UpU8555 Vertical DownD6844 Horizontal RightR8252 Horizontal LeftL764C New SpeedS8353 Robotic Arm Protocol: ASCII Packet RotateR Sensor OnON Sensor OffOFF AcknowledgementACK Turntable Protocol:

Functional Flowchart

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 Microcontroller Overview

Robotic Arm Assembly Overview

Robotic Arm Operational Flowchart

Robotic Arm Firmware Initializes microcontroller’s IP address via DHCP Sets up a listening socket on port 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

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 1/500 th of a second If motion is desired, every interrupt sends a pulse to the stepper controller until 500 steps have been made

Infrared Background Information

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

Thermal Proof of Concept

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

Turntable Assembly Overview

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 Wait until connections are established Pass control to the main OS task

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

Turntable Hardware Motor 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

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