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ECE 445: Printing Press. Jerome Han John Doherty Adriana Siu TA: Kieran Levin Profesor: Scott Carney. Introduction and Objectives. Overview. Benefits and Features. Mechanical Setup The film system The print system External control panel Ultrasonic sensors.
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ECE 445: Printing Press Jerome Han John Doherty Adriana Siu TA: Kieran Levin Profesor: Scott Carney
Introduction and Objectives Overview Benefits and Features • Mechanical Setup • The film system • The print system • External control panel • Ultrasonic sensors • Automation of all mechanical procedure (saves labor cost and time) • More cost effective controller • Easy user interface • Programmable
Content: Mechanical Build • Unwind Roller • *1st set for tension/distance(2 rollers) • Printing (3 rollers) • Rewind Roller • 4 sensor mounts • 2 bottom • *2 sides
Content: “Velocity Controlled Motor” • Analog Voltage Reference α Speed • Pn300=12V/rated speed (12V=3000RPM, 6V=1500RPM) • Microcontroller outputs PWM at f=490Hz • PWM=>RC LP Filter=>Analog Voltage • *Relation: Duty Cycle of PWM vs. RPM:
Content: “Position Controlled Motor” • Pulse Train Reference α • Speed of motor (frequency of pulses) & • distance traveled by motor shaft (number of pulses) • Time b/w pulse trains α • Delay b/w distance traveled • Reference units:
Content: Front Panel • On-Off switch -Turn on and off the motors and disables the control panel • Potentiometer -Controls the speed of the velocity motor with in a jog mode • Matrix Keypad -Changes the presets of the motors • LEDs -Indicates the status of the motors • Further Tests • Switch
Content: Ultrasonic Sensors Theory • Sends ultrasonic waves to object and receives reflected waves for detection • Use 1 digital pin for trigger output/echo input • Operating Frequency of 40 kHz • Theoretical Minimum and Maximum range from 3cm to 4m
Content: Ultrasonic Sensors: Discussion and Tolerance • Sources of Error • Data acquisition from oscilloscope • Measurement of width from oscilloscope • Inconsistency in object detection • Placement in mechanical setup • Improvement • Tolerance Analysis
Recommendations and Conclusion: Design Improvement • Motors • Balance velocity voltage output (*D/A converter, tension control) • Mechanical: More distance for no crinkle in paper • Front Panel • LCD screen • Sensors • Mechanical: Side placements too low • Printing Press worked! • Different speeds and distance b/w prints
Ethical Concerns • Hardware malfunctions • Could hurt somebody (ink in their eyes) • Getting their hand caught in the rollers if the ultrasonic sensors malfunction and don’t detect hand • SRf05 low cost so they can get damaged easily • Control panel buttons are very small and this might confuse the operator (no red for stop or green for go buttons)