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Automatic Windshield Wiper
Designed at the University
of Michigan by Adam Duddles, Jennifer Atkins, and Michael Lee |
Description
The Automatic Windshield Wiper system removes dirt and rain without the need for driver intervention. If rain is detected, it is immediately wiped away. The system also continually scans the windshield for dirt, washing the windshield if necessary. A baseline scan insures accuracy in dirt detection and terminal output allows easy verification.
Interfaced
Components
·
Sharp GP2Y0A02YK
Infrared Object Detector
o
The IR sensor was
mounted on a platform and used to perform scans of the windshield. This would return analog voltage levels to
the analog-to-digital converter.
·
Wiper Limit Switch
o
The switch was placed on
top of the windshield and used to control the starting and stopping of the
windshield wiper. It returned (an
extremely noisy) analog voltage level from which we extracted a “good” value to
determine its position as on or off.
·
2 Futaba S3003 Servos
o
Interfacing to the
Servos required a pulse-width modulated signal operating at a frequency of 50
Hz. We accomplished this by dividing
down the MPC823 internal clock and using Xilinx macros to start the pulse every
20 ms, as well as stop them after the appropriate length.
·
Wiper Motor and Washer
Pump
o
The motors controlling
the windshield wiper and washer pump required a 12V input, which we
accomplished from interfacing the circuit board’s voltage along with a separate
12V voltage source by using a series of relays and transistors. They essentially operated as an on-or-off
signal: they would move the wiper or pump the water while on, and rest while
off.
Most Difficult Issue
·
The windshield wiper
system was intended to have a capacitor input which measured the relative
moisture levels between two strips of conductive tape. Using these moisture level values, the
system was supposed to be able to determine how wet the windshield was, and
perform the appropriate number of wipes to clean the windshield. However, we were unable to complete this
task due to the erratic behavior of the capacitor.
Visuals
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Front
view of windshield wiper system
