Christmas Light Display
Due to the duty cycle of the lights (flashing on and off), my power bill was $1.50 extra per day, or $45 for the entire month the lights are on. An old PC ran a timer program and Power Point presentation and when the time counted down to zero, an output pulse from the computer turned on 10 relays that applied power to the entire display, whether I was there or not. All the computers were set to "boot" automatically. At 10:30 PM the same computer turned off the relays, and got ready for the next cycle starting at 6:30 PM the next day. On the monitor for the power point presentation I mounted a wireless camera with microphone so I could catch people's reactions and watch for vandals.
I started my hobby of building a Christmas displays in 1982 with, a 14 foot high "Christmas tree" decorated with 200 C9 (big) incandescent lights that flashed in trivial pattern.
I followed up the next year with a display called "Snowflakes" that used the very small 1 watt incandescent bulbs that normally were series connected. I had to use 36 volt transformers to be able to use them individually (actually in a matrix)
Thus a hobby was born, and every year from then until 2002 I kept adding and upgrading until I had this (link below), a 6600 light, 10 motor, 12 relay, 3 computer light display:
I quit in 2002, anticipating a move across the country, and so dismantled, scrapped, and sold everything except the Snowflakes which I upgraded with 5 watt bulbs. Not satisfied with the brightness of these as seen from across our cove (700+ feet), I made new Snowflakes, 7 feet in diameter using the big C9 (7W) Christmas bulbs.
Along the way through all variations I upgraded the electronics from simple Motorola D5 evaluation kit to my own PCB with PIC MCU on board and custom triac controller boards. I took the snowflakes out of service in 2018 and made a Star, using Arduino UNO MCU board, and custom driver boards for high power LEDs that had to be brighter than the C9 incandescent boards.
Click on a link:
I'm working on another Snowflake display for 2019, using everything I learned from making the Star.