I just received a set of cheap (but surprisingly well built) LED meteor lights which I bought on ebay recently. I had them running for a while and then noticed that one of them was doing a very weird multiple echo pattern. At first I though the processor had crashed or glitched and lost track of the effect, but then I realised that it could possibly be a shorted LED bridging two matrix lines together. Resetting the effect didn't help, so it almost certainly is a duff LED causing the weird ghosting.
These effects tend to use tri-state multiplexed LEDs, otherwise known as Charlieplexing. This involves using the matrix lines in three states. Positive, negative or floating. It means that only one LED can be lit at a time, so for multiples they have to be scanned quickly to make them appear lit continuously. The upside is that you can drive a HUGE number of LEDs with just a few lines. You can work out how many by multiplying the number of control lines by the same number minus one. So for five lines you multiply five by four to give control of 20 LEDs. With eight lines you could theoretically control 56 separate LEDs (8 x 7).
I've never come across a Charlieplexing fault before, so it's quite intriguing. It means I have one dead LED that has effectively shunted out its partner LED (in reverse parallel), but the visual effect actually looks quite interesting.
These effects tend to use tri-state multiplexed LEDs, otherwise known as Charlieplexing. This involves using the matrix lines in three states. Positive, negative or floating. It means that only one LED can be lit at a time, so for multiples they have to be scanned quickly to make them appear lit continuously. The upside is that you can drive a HUGE number of LEDs with just a few lines. You can work out how many by multiplying the number of control lines by the same number minus one. So for five lines you multiply five by four to give control of 20 LEDs. With eight lines you could theoretically control 56 separate LEDs (8 x 7).
I've never come across a Charlieplexing fault before, so it's quite intriguing. It means I have one dead LED that has effectively shunted out its partner LED (in reverse parallel), but the visual effect actually looks quite interesting.
I have a few of these sets and all worked, all leds lit, but after a number of hours, they started showing the above issue. I just left it and assumed they were cheaply made, but the next day when the timer switched them on again, all leds were fine, pattern running as it should and no issues. The problem returned on random days but the leds that appeared out seemed to just be taking a break and would work again after a lengthy "off" period. Strange.
Clive, I love all your videos, and you beautiful voice and accent just add to the enjoyment. Also, my friend lives in Glasgow and is another fan of yours, he also loves to take things to bits and make new things out of them, you should meet up 🙂
15fps video 🙁
I've had to repair all of mine , usually only one fails per strip , got both types , white and coloured , the led fails short circuit , either remove or replace to get the correct chase pattern again , thanks for the videos Clive , always a great watch and source of info
all ur videos r awesome, can u hack on all in one solar power led street lights. every thing fit into 1 panel, it so interesting.
Clive can you please explain again how they are multiplexed- preferably with one of your famous drawings!! Thanks 🙂
All I have in my head from looking at those is warp plasma transfer conduit…
Your videos and channel are good,but you talking so fast with accent and sometimes is hard to understand i am study English only in movies.
I bought a few sets of very similar tubes and in each case the power supply was a capacitive type. Very dodgy indeed. Ultimately it didn't worry me as I run them off the output of a ELV lighting controller board.
Who else noticed the plug had no earth pin?
The quality was so high, it didn't even last one day without two failures!
your lights over your work table are leds how did you get rid of the flicker ? or does your camera just not pick up on that I find that mains leds or ones with a controller tend to flicker at a very perceptible rate for me like florescent which tend togive me headaches