BTTF Delorean SID Panel
My friend Tom has been working on converting a Delorean into a Back to the Future replica for a few years. In 2011 he asked me to make him a custom circuit for his SID panel. The SID panel is the name given to the bank of 200 LEDs that sits behind the driver seat.
In the movie the panel lights up in ten rows of 20 LEDs with the height corresponding to the speed of the car. Tom's main interest was in display so we decided on having three switchable presets, full on, half full as shown in the "parked" screenshot above and a low level on. Once Tom gave me the custom made panel with the accurate lenses installed I got to work on the circuit. 200 LEDs, even low power ones like we were going to use, draw a lot of power so I had to multiplex the output. I designed a circuit using an arduino microcontroller that would accept input from toggle switches to set the pattern and output to a series of shift registers and transistor arrays.
With the circuit designed I started by building the LED matrix. I ran the anodes vertically and the cathodes horizontally.
Once I had the display built I could test the circuit and work out the pattern program for the microcontroller. The more LEDs that are on the dimmer the overall display gets from multiplexing. I was able to mitigate this somewhat by changing the number of LEDs on at any one time and the frequency of the multiplexing plus the overall power running to the panel. It's a bit of a balancing act to keep it from flickering but not drawing too much power.
Once I had the microcontroller programmed and the circuit working I just had to make it all fit in the panel housing. I'm still not sure how I pulled it off but I managed to squeeze it all in. I had to put a heatsink on the voltage regulator due to the power required when the whole panel was on but overall the circuit works great.
Tom installed it with no problems and it worked like a charm.