RGB123 matrix not working anymore

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  • Hello,
    My RGB123 16x8 matrix was working perfectly and for no reason it's just stopped?
    The wiring is: GND => GND, DIN => B15, 5V =>BAT
    I've copied the code from here: http://www.espruino.com/RGB123
    But nothing happens, every pixel stays off?..

    I've tried debugging the following:
    Matrix is broken? NO. I've tried it on an Adruino and it works fine. I can even power the matrix from Espruino while sending data from adruino and that works. So it must be something to do with the data being sent from B15?..

    Pin B15 is broken? NO. I can use a WS2812 strip on pin B15 and they work fine

    Some wrong with Espruino? don't think so as I've tried on my second espruino and same results?.

    Any ideas what I should try next? this is driving me mad.

  • Just tried it here and it still works fine on 1v62.

    Honestly not sure what to suggest. I used 1v62, copied the code from that page exactly and plugged my RGB123 in exactly as you did and it worked perfectly.

  • It's still worth checking the power supply - maybe putting a bigger capacitor across GND and VBat.

    While Arduino may work, it'll be outputting 5v which may mean the display isn't quite as picky as it is for Espruino.

  • What size of capacitor would you suggest?

  • I'd say 47uF or over. I've got a 470uF on mine, which is probably overkill.

    How did it stop working though? Was it all wired up and going, and one day is stopped - or did you plug everything in and this time it didn't work?

  • Something that could have caused it. It was all wired up correctly and working in the PIN stated above and while turned on I unplugged the matrix GND/5V from Espruino and plugged them directly into a 5v 0.5A wall adaptor .
    Now I've gone right back to basics and just trying to get it to work again on Espriuno.

    I don't power is the problem as I can power the matrix from either Arduino/Espruino/5v adaptor including the controller it's self. So it has to be something to do with the B15 data out? But if so then why does the WS2812 strip work Ok on B15?

    It's is becoming a real mystery.

  • Is the Espruino ground tied to the ground of the LED matrix? It should be.

  • @DrAzzy it is yes.
    When I connect the 5V to the matrix I often see some of the pixels randomly flash on in one of(red/green/blue) one only for a fraction of a second and then everything goes back to off.

  • Hi guys,
    I've got it working but only if I connect the Matrix 5v line to the Espruino 3.3 pin, not BAT.
    And when I do connect it to 3.3 or power on Espruino it crashes and restarts Espruino before continue as normal.
    Any ideas why this is happening?

  • The reset is probably because as it gets plugged in there's a brief current surge that's resetting the Espruino? It didn't do that on my Espruino though (I have the 8x16 too RGB123 too), at least not powering it off VBAT (I didn't try on 3.3 - that's probably not high enough voltage for the LEDs).

    Is this what you're seeing?

    Matrix + Matrix GND Matrix Data In Result
    VBAT Esp. Gnd B15 Nothing
    +3.3v Esp. Gnd B15 Works?! What?!
    Ard. +5v Ard. Gnd arduino output Works
    VBAT Esp +Ard Gnd arduino output Works

    What code are you using? I'd use the simple example, where they don't use the graphics library (in order to take any other issue out of the equation, and to ensure that you don't try to turn on too many pixels for your power source to handle - which is easy to do, since each LED on full power will pull 50ma, and you have 128 of them) - something like this:

    SPI2.setup({baud:3200000, mosi:B15});
    SPI2.send4bit([0,0,255,0,255,0,255,0,0,2­55,255,255], 0b0001, 0b0011); 
    

    Also check with a different pin for good measure (SPI1/A7 is a better choice than SPI2, because SPI2 is used for the SD card, so you'll get garbage on your WS2812's if you access the SD card)

    SPI1.setup({baud:3200000, mosi:A7});
    SPI1.send4bit([0,0,255,0,255,0,255,0,0,2­55,255,255], 0b0001, 0b0011); 
    

    I can't come up with any explanation consistent with your observation that WS2812 strip on Esp. GND, VBat and B15 works, other than bad connections. I'd ohm out all the connections, and make sure everything was actually making contact. I've had dupont connectors that didn't make proper contact with certain headers, or ones that I had to push down the wire on to get it to make contact, and it'll drive you mad if you're not on guard for it. This could also jive with your report that the problems started when you hooked it up to an external power supply (maybe you forced the connector over pins a little too large, or something like that - and it works on the arduino because the pins it has are slightly different and make better contact. Or you cracked a solder joint hooking it up, so now power doesn't make contact if the wires are angled a certain way).

    But yeah, I think it's likely a connection issue, as boring as that is.

    Edit 1: Ugh - I thought I could use markdown to make tables here?

    Edit 2: The more I think about this, the more I wonder if your test code is just trying to turn on too many LEDs at too high a brightness, triggering the power source to shut down (or momentary voltage droop that resets the WS2812's so they forget that you just told them to turn on - that's what Gordon uses the cap across power and ground on the panel to prevent)... and if you're using test code that doesn't turn on so many LEDs on the arduino, that'd explain that, and if you're running off espruino on 3.3v so the leds barely turn on, that would dramatically lower current, maybe making it possible to run the test code? It's the most plausible explanation I can come up with, short of a connection issue. (as an aside, that 5v @0.5A supply you were using is woefully insufficient for a panel of that size. )

  • Uh, is there a missing post here? The topic listing says there was a post here today, but I can't see it...

  • Ahh, yes - there was a spam post that got removed.

    First one in ~12 months though, so not bad going!

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RGB123 matrix not working anymore

Posted by Avatar for Owen @Owen

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