Electromechanical Timer Replacement - 320Volt

Electromechanical TimerReplacementLawn Sprinkler System Using a PIC12C508Author:Aroldo CarvalhoBoca Raton, FLUSAemail: aroldo@gate.netAPPLICATION OPERATIONThis Lawn Sprinkler System is an electronic timer thatcan be programmed to activate and deactivate thesprinkler electric valve.You can program it to activate anytime up to fifteendays, with 1 to 15 minutes for each sprinkler circuit. Thesprinkler circuits will vary depending on the lawninstallation. The number of sprinkler circuits areprogrammable.There will also be a bypass switch that will allow theuser to activate the electric valve bypassing theelectronic circuit at any time.To improve the system a backup battery would hold thedata in case of a power failure.OPERATIONThe user has an LCD Display and three push buttons toprogram the unit as shown in Figure 1.FIGURE 1:SIMPLE DIAGRAMLCD DisplayDay Hour Minute1. Set the number of sprinkler circuits.pushbuttonsTo set the number of sprinkler circuits, press andhold the day and hour buttons together, thenpress the minute button to select from 1 to 8 circuits.2. Select the day, the start and end time for eachsprinkler circuit.Press the day button to scroll from 1 to 15, thenpress the hour and minute buttons to select thedesired sprinkler circuit. Then enter start hourand minute and stop minute. The duration can befrom 1 to 20 minutes per sprinkler circuit.Repeat the above steps for each circuit.Microchip Technology Incorporated, has been granted a non-exclusive, worldwide license to reproduce, publish and distribute all submitted materials, ineither original or edited form. The author has affirmed that this work is an original, unpublished work and that he/she owns all rights to such work. Allproperty rights, such as patents, copyrights and trademarks remain with author.© 1997 Microchip Technology Inc. DS40160A/1_004-page 1