The timer is designed to set and up to 99 countdown minutes 59 seconds. After the completion of a given interval are connecting load to the mains using a solenoid relay leg.
Schema based on microcontroller PIC16R628A. The indication is realized on a standard dvuhstrochnom 16-digit display (1602). Management with four buttons. S4 button is used to reset. S3 button you can choose that setting, minutes, or seconds. S1 button serves for proper installation time, it set as minutes and seconds (that is selected the button S3). S2 button serves to start the timer and stop it if you need it.
At the conclusion of the time interval occurs a logical unit on port RB6 (12). Transistor VT1 HA whats and through relay K1 includes the load (the load is connected between terminals 2 and 3, and 220V mains voltage is applied to terminals 1 and 2.
Источник питания – бестрансформаторный. Состоит из гасящего конденсатора С7, выпрямительного моста VD1-VD4 и стабилитрона VD5, а так же, сглаживающего конденсатора С6. На С6 напряжение 12V, оно служит питанием обмотки реле К1, а напряжение 5V для микроконтроллера создает стабилизатор А1.
Before programming set to work with a built-in generator 4 Mhz.
Author: Savos'kin V. S.
