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Switched-Controlled Turntable. Name: Dean McDonnell Supervisor: Dr. Maeve Duffy. Objective of Project. To Design and Build a Switch-Controlled Turntable Controlled through an infra-red remote control Full 360 degree turn, bi-directionally Stepped in 90 degree angles
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Switched-Controlled Turntable Name: Dean McDonnell Supervisor: Dr. Maeve Duffy Electronic Engineering Final Year Project
Objective of Project • To Design and Build a Switch-Controlled Turntable • Controlled through an infra-red remote control • Full 360 degree turn, bi-directionally • Stepped in 90 degree angles • Addition to project includes a second motor • Design Issues: Fit under assortment of beds and Portability Electronic Engineering Final Year Project
Previous Design • Another version designed and built in the USA • Two students from University at Chapel Hill • Use by children with severe and profound disabilities at Lake Wood Elementary School • Children were unable to retrieve toys independently • They could not choose between items when presented multiple options • Table required auditory, visual and tactile feedback • Needed to fit the needs of a variety of children • Named “The Lazy Susan” Electronic Engineering Final Year Project
Building of Previous Design Electronic Engineering Final Year Project
Previous Design • Advantages were immediately noticed • Allows access to multiple toys from a single location • Consists of partitions used to segregate the toys from one another • LED’s and spoken messages are also integrated • Provide visual stimulation and auditory feedback • Very important for teachers, therapists and children Electronic Engineering Final Year Project
Operation of Previous Design Electronic Engineering Final Year Project
Initial Step Infra-Red Execution Infra-Red Receiver Microprocessor Motor Drive Motor Table Electronic Engineering Final Year Project
Finding the Motor • Stepper Motors were a must • Datasheets of different motors researched • Tests carried out on different motors • Results had to show that motor is capable of rotating a mass of 5 kilograms • Also needed to be cost effective • Rotate the mass within approx. 7 seconds without exceeding 12 volts • Minimal stopping and starting times Electronic Engineering Final Year Project
Testing the Motor • Initial test involved having no load • Select few motors were advanced to second test • Second test involved load of 5kg • Load tied onto coupling that was placed on motor • Results achieved determined the appropriate motor • Chosen Motor was the MFA COMO DRILLS 919D SERIES Single Ratio Gearbox Electronic Engineering Final Year Project
Motor Test Results Electronic Engineering Final Year Project
Finding the Motor Controller • H-bridge was chosen for the task • Used to control the polarity of the motor • Used to turn the motor bi-directionally • Also used to “brake” the motor Electronic Engineering Final Year Project
Testing the Motor Controller • The controller placed into the breadboard. • Voltage supply added • Motor attached to breadboard • Motor turned bi-directionally as well as “braking” when needed • Oscilloscope was used to observe wave patterns Electronic Engineering Final Year Project
H-bridge Characteristics • L293 used for this project • Two separate sides - Only one side needed • Pin1 – Switch Enable • Pin2 – High Pulse (Oscilloscope Channel 1 Connected) • Pin3 – High Output to Motor (Oscilloscope Channel 2 Connected) • Pin4 – Ground Also Connected to Pulse Ground • Pin5 – Ground • Pin6 – Low Output to Motor • Pin7 – Low Pulse • Pin8 – Voltage In (Connected to Pin16) Electronic Engineering Final Year Project
Motor Controller Results Shows the stepping changes on the H-bridge Electronic Engineering Final Year Project
Testing the Microcontroller • 8051 ADuC831 used for this project • A program is needed in order to test the 8051 • Programmed in C • After weeks of testing, the program finally resulted in direct communication between the computer and the 8051 Electronic Engineering Final Year Project
Microcontroller Results • Direct communication between the computer and the 8051 • LED flashing indicates this • Hyper-terminal reads in the character ‘1’ from the 8051 (seen in next slide) Electronic Engineering Final Year Project
Microcontroller Results Electronic Engineering Final Year Project
Addition to Microcontroller Results • Addition to the program has been achieved • This addition involves the motion of the motor through the H-bridge • The motor can be controlled to turn clockwise as well as anti-clockwise • The motor can also be stopped or “braked” by the H-bridge Electronic Engineering Final Year Project
Next Steps • Next steps are based around the infra red user device • This involves the building of the infra-red receiver • After that, the project will lead on to getting the second motor • This second motor will control the upwards/downwards motion of the table • Once this motor is coded, the physical designing of the table will follow Electronic Engineering Final Year Project
Questions? Electronic Engineering Final Year Project