Summary of Night Light Saver V3.2 using PIC12C508
The SAVER V3.2 is a night-light controller built around a PIC12C508 microcontroller and a small triac (MAC97A6). It uses a transformerless capacitive dropper power supply, a 5.1V zener regulator, a 32 kHz crystal, a momentary button to set time, and an LED indicator. The firmware (SAVER.hex) sets on/off schedule (19:00–22:00) and can set time to 8:00 via S1; source C files can be recompiled with the PCW PIC C Compiler.
Parts used in the SAVER V3.2:
- PIC12C508 8-pin microcontroller
- MAC97A6 triac
- 0.22 uF capacitor (Xc) for capacitive dropper
- Diodes for rectification
- 100 uF filtering capacitor
- 5.1V zener diode
- 32 kHz crystal (X-tal)
- Momentary push button (S1)
- Small dot LED
- PCB or wiring and supporting passive components (resistors as implied)
Introduction
It’s time for 8-pin microcontroller Microchip PIC12C508, the SAVER V3.2, my latest design of a device that turns a night light on and off everyday. The circuit uses only a PIC12C508 8-pin CMOS micontroller and a small triac, MAC97A6. The Saver V3.2 also demonstrates the use PCW PIC C Compiler.
Circuit Description
The schematic of the SAVER V3.2 is depicted in Figure 1.A transformerless power supply uses Xc of a 0.22uF capacitor to limit current providing about 10mA current source. The diodes rectifies ac current to dc current which in turns charged to filtering capacitor, 100uF. A 5.1V zener diode provides dc supply ~5V to the PIC12C508. The microcontroller circuit runs with low power 32kHz X-tal. GP2 connects a momentary button for setting time to 8:00. GP1 drives small dot LED that blink every 5 s for normal running. GP0 directly drives with source current to a small triac MAC97A6.
Software
Saver.hex is HEX file suitable for writing the code to the PIC12C508 chip. This file sets time to 8:00 when press S1 once. Time on and off is set to 19:00 to 22:00 everyday.
The original source program SAVER.C and SAVER.H was written in ‘C’ language. User may change set time when press S1 and change time on/off.
To recompile the source file you need a PCW PIC C Compiler from CCS.
For more detail: Night Light Saver V3.2 using PIC12C508
- What does the SAVER V3.2 do?
It turns a night light on and off every day according to programmed times. - Which microcontroller is used in the SAVER V3.2?
The circuit uses a PIC12C508 8-pin CMOS microcontroller. - How is the power supply implemented?
A transformerless capacitive dropper using a 0.22 uF capacitor limits current, followed by rectifier diodes, a 100 uF filter capacitor, and a 5.1V zener regulator. - What component controls the mains load?
A small triac MAC97A6 is used to drive the load. - How do you set the time to 8:00?
Press the momentary button S1 once to set the time to 8:00. - What are the default on and off times?
The device is set to turn on at 19:00 and off at 22:00 every day. - What indicates normal operation?
A small dot LED driven by GP1 blinks every 5 seconds in normal running. - Can the firmware be changed?
Yes; the original source SAVER.C and SAVER.H can be modified and recompiled with the PCW PIC C Compiler.
