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Last Updated on: Thursday, November 30, 2017 07:43 AM

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Garage Door Closer
Designed by Dave Johnson, May 14, 2011

  

Problem:  Need circuit to automatically close the garage door after it is left open for a given period of time.

 

Solution:  The circuit below is designed to automatically close a garage door, if it was left open for a long period of time.  A reed relay and magnet combination sense when the door is fully open.  An ultra low power voltage comparator oscillator and two 74HC4040 ICs are used to generate the timer.  The jumper or a switch can be used to select a time of 30 minutes, one hour or two hours.  The circuit draws only about 2ua so a pair of AA alkaline cells would keep the unit running for many years.

 

This commercial devices, shown above, contains a battery powered circuit which uses a tilt switch to detect the horizontal orientation of the garage door.  It has a timer and a RF transmitter to send a command to the opener to close the door after a period of time.


Click on Drawing Below to view PDF version of Schematic


garage door closer designed by David Johnson

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DC Magazine, May 2011, Page 6:  Garage Door Closer


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