Agenda Introduction Purpose Objectives Specifications Final Product Parts Fabricated Control System Parts Features Functionality Battery Facts Flow Diagram of Code Future Considerations Conclusion
PurposeDesign a mechanism to electrically operate an umbrella which allows a wheelchair-bound individual w/ limited mobility to shield themselves from precipitation and direct sunlight, w/out the need of physical strength and/or assistance from others.
Solution – UmbreMech!
Objectives Provide full coverage for the wheelchair occupant Allow clearance between the occupant and the umbrella while deployed Design an easy-to-use user interface to control the umbrella Intended for electric wheelchair use.
Specifications Attachable/Detachable Shade < 40 in. diameter, Case < 12 in. diameter 12 VDC/2.5 Amps Product ~ 30 lbs Height of arm < 2 ft Corrosion resistant material Deployment/Retraction time < 20 seconds
Final Product – Exploded View
Parts – FabricatedRapid Prototyped Turntables FlangesGears Motor Mount/Gear Mounting/ Umbrella Support Motor Mounts & Pulley Turntable Supports
Parts - Control System Arduino Mega 2560 3 x SideStep Chopper Motor Drivers Battery 12 VDC 9Ahhttp://arduino.cc/en/uploads/Main/ArduinoMega2560_r2_front.j http://www.probotix.com/image/SideStep.jpg http://ecx.images- pg amazon.com/images/I/4143kOFXJpL._SL500_AA300_.j pg 2 x Nema 17 Planetary Nema 17 Stepper Motor Misc Parts Gearbox Stepper Motors http://www.phidgets.com/images/3312_Big.jpg http://www.phidgets.com/images/3303_0_Web.jpg
Parts – Control System (Cont.d)
Features - Control System Rotation – 360 Tilt - 45 in either direction Flip Up/Down Power Saving Modes – Using a counter Save motor power when idle or in the starting position Location Maintained in Memory - EEPROM Fail-Safe with Power Loss
Functionality – Block Diagram Orange Arrows = Power Connections Blue Arrows = Input/Output
Battery Facts Current setup uses 12V 9Ah Sealed Lead Acid Rechargeable Battery (Inexpensive for demonstration purposes) Typical electric wheelchair battery is 24V 600Ah Design is adaptable. Motor drivers can handle 24V input Voltage Regulator (LM317) needed for Arduino - 24V to 12V decrease.
Flow Diagram of Source Code Legend Conditional Statement (Is Button Pushed?) Rotate Corresponding Motor in Certain Direction
Future Considerations Further Constraints Reduction of Cost and Weight Further Safety Design Flexibility Profitability of Design Incorporate Sun Sensor Smartphone Application
ConclusionAs the handicap populationgrows, technological innovations such asthe UmbreMech will service the growingneed for automated systems onwheelchairs.
Analysis for Pulley SystemPulley 1 Body A Body B Body C .C B . .C . . . k Assume zero friction: . APulley 2 . z The circumference of Pulley 2 = z