PDS / April Update


I initially waited to construct the new LED matrix until I had a grip on the power requirements. My old board was 2240 LEDs running from a 5V 70A 350W power supply, although it just good enough (I know this because when I run the whole thing at full white, it flickers). However, even as I type this I become unsure of my knowledge — Eric Rosenthal told me that when white LEDs turn yellow that means too much current. Overall, my deficiencies in understanding electricity is something that I wished to address, and measuring power requirements for the new board was a means of doing so.

I started out by scheduled a meeting with Eric Rosenthal, power guru of ITP. He recommended that I first find the “peak instantaneous¬† voltage” of my old LED board by connecting a 1 OHM resistor and using Ohm’s Law to calculate exactly what is the amperage that I require. The different patterns that I displayed drew different amounts of current, depending on how many LEDs were on and what colour the LEDS were.

However I didn’t really do a good job at measuring the current this way. The first 1OHM resistor I used was a tiny one, and when I made the circuit in series, nothing happened. I used other resistors and mostly, nothing happened on the board since there was not enough current. One resistor smoked and I suspect I blew other resistors also.

Later, after consulting with Jeff Feddersen, I learned that different resistors had different Wattage. I would need a much heartier resistor to do what I needed. However, even using 5W and 10W 1OHM resistors in the ITP shop, I still could not calculate what I needed. Time kept ticking and I just wanted to start making the damn thing.

So I decided that if my current power supply worked for a 2240-pixel LED matrix, it would definitely be enough to work on a 1850 and 1900-pixel LED matrix, since I decided to do it in two modules.


I put up the metal L brackets according to plan and the paper was not as tight as I wanted. The thin part of the L bracket could be the culprit. Next steps on this will be to use nails with big heads to increase surface area that sandwiches the paper.


From previous experience I know that each LED strip needs its own connection to the power supply, rather than running the power through the entire strip (which does not do the job). However when I was using a stiff piece of plywood to mount the LED strips to, I could just staple the 12 AWG wire to the board and everything wouldn’t move, including the solder points.

But since I am using a flexible piece of vinyl, I face the challenge of needing a stiff 12 AWG wire soldered to each LED strip, however it needs to be attached to the flexible vinyl. Something stiff attached to something flexible. I consulted Ben Light on this. After the consultation and two hours of deep visualization while sitting on a display rack in Home Depot, I decided upon a low tech solution: I would staple a piece of plywood to the back of the vinyl with heavy-duty staples. And I would staple the 12 AWG to it too. Just like on the old board.

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