12mm Diffused Thin Digital RGB LED Pixels (Strand of 25) not working?

[arrasmith]

Hello! I just bought several 12mm Diffused Thin Digital RGB LED Pixels (Strand of 25) and was trying to get the sample program to work and then start a project from there. I can't get the Adalight project to work. I have searched the forums and google to no avail. I am working off the tutorial and have checked all the wiring as suggested over a dozen times. I have tried all the troubleshooting suggestions: verified I am using the input side (female connector side). I bought a couple of the power adapters too (10 amp one) and switched those out. I switched out the led string. I changed from using the connector I bought to breadboard connectors. I taped the loose ends. I used a volt meter to check the power (5.5 on each end). Essentially everything has been swapped out and checked (a lot). The result is the same. Only one LED lights (the only closest to the arduino and furthest from power). So my first question is: what is supposed to happen to the LED string when power is first applied? Should only one light up? None? all? last state of each?
Second question: The only slight variation from the tutorial is I am using the Mega 2560 (since I already had one) vice the uno but I think I read that is ok but overkill). Has anyone else used the Mega 2560 with these LEDs or have any idea if it would be the problem?
Anyone have an insight to what I appear to be doing wrong? Since it seems others are using these, it must be something really simple (and stupid on my part)

[adafruit_support_bill]

So my first question is: what is supposed to happen to the LED string when power is first applied? Should only one light up? None? all? last state of each?

The state on power-up is 'undefined'. You need to run a sketch to set the state of the leds.

Second question: The only slight variation from the tutorial is I am using the Mega 2560 (since I already had one)

Not a problem. The Mega works fine and the extra RAM is good if you have a lot of pixels.

Have you tried running the StrandTest" example sketch? Post a photo showing all your connections.

[arrasmith]

Thank you for the response. I appreciate the help.

I haven't tried other sketches; I have been using the LEDsteam (adalight) sketch. There is a sequence at the beginning of that to flash the lights to red, green, blue, then off. The behavior I get the first one to go red, green, blue, then stay on a light blue. None of the others have done anything. Since the notes in the sketch say this is to verify the wiring is correct (up to 25,000 less), I haven't been adventurous enough to try other sketches and introduce another variable in the troubleshooting (unless, of course, the sketch is the problem).

One wierd observation with the sketch though is I can only get the red, green, blue (then stay on blue) when I press upload from the sketch. Once upload I would expect the reset button on the aruduino to restart that sequence but it does not. If I do another upload from the sketch, the red, green, blue sequence works again (but still with the problem of only the first one and staying on blue).

Another observation, that probably is expected, is on both the led strings I have tested with, if I move the wiring around with it plugged in I get the first bulb to change color. I assume this is just noise but thought I would mention it. I did this because somewhere I saw to press on the connectors to ensure they are solid if the downstream leds don't light. Doing this had no effect; only the first led does anything.

I am including photos as requested
I really appreciate the help and I am very excited to do my project with the leds so hopefully a simple solution is found soon

ariel

IMG_0288.jpg (27.8 KiB) Viewed 784 times

IMG_0289.jpg (39.42 KiB) Viewed 784 times

IMG_0292.jpg (31.23 KiB) Viewed 784 times

[pburgess]

If using an Arduino Mega, try moving the wire from pin 11 to pin 51, and from pin 13 to pin 52 (these are on the double-row pin connector).

LEDstream does some lower-level hardware stuff that's tied to specific pins that will be different for each board. If in doubt, go through the tutorial with the 'strandtest' example -- this can be configured to use any two pins.

[arrasmith]

Thank you for your response.
Yes, I thought about that and tried that. Just to be thorough (or simply crazy), I tried 11 to 52 and 13 to 51. I still only get the first LED to do anything. The difference in switching the pins is: instead of a blue glow at the end of the init sequence, it is green; actually the init sequence won't work in this config and I can't get it to do the red, green, blue flash at all in the config.

[arrasmith]

Ok, I tried the strandtest sketch and got it working! These leds are cool! I am very excited about working with them!

I am still curious why the ledstream sketch for the adalight project doesn't work for me. I suspect now that it has something to do with the data and clock pins (and the fact I am using a mega), but I tried the 11/13 combination as well as the 51/52 combination (for mega).

I did have to download the ws2801 library to get strandtest to work but I don't need that library for ledstream since it uses SPI, correct?

I can move on with my project now using the ws2801 library but don't want to miss a learning opportunity on SPI, the mega, and the leds.

Thank you all the help.

[Rads]

I've been stuck with the same issue for the last week, I use WS2801 flat type LED's, couldn't get LEDStream to work but could get StrandTest. Moved the pins to 11 and 13 downloaded LEDStream and no luck.

Driving me mad, I've checked the wiring, swapped the pins but nothing, the best I can get is some of the LED to stay on, no initialisation sequence when downloading LEDStream.

Is there a way of making LEDStream use pins 2 and 3 like StrandTest?

I'm using a UNO and 10A PSU, tried two sets of LED's both doing the same.

Any help appreciated

[pburgess]

Rads: if using the flat pixels, try turning the strand around (so you're connecting the Arduino to what the tutorial labeled the "out" end). I think the factory may have made a surprise change recently, and the tutorial doesn't reflect this yet.

[Rads]

Thanks for the assistance, I'll give that a go on Monday when I get home. So that means I need to use the other type of connector?

If that is the case, why would StrandTest work but LEDStream not? If I had the LEDs backwards, then it shoudln't work for either sketch should it?

[pburgess]

Oh! You're right...if the strandtest case is working, then you're on the right end of the strip, disregard my suggestion.

Could you post a photo that clearly shows your wiring between the Uno, LED strand and power supply?

[Rads]

This is my connection for strandtest, all working and I can see voltage on pin 2 varying 0~2.5 V

With LEDStream downloaded to uno I see pin 11 at 4.4V but no modulation, TX light is flashing.

Can I change LEDStream to use pins 2 & 3 instead of 11 and 13?

Thanks

[Rads]

Any chance of assistance? This is getting frustrating

Only ledstream isn't working. Can I change pins to 2 and 3?

[pburgess]

Hi Rads, sorry for the delay, I've been out sick.

LEDstream relies on hardware SPI to help with the simultaneous tasks of reading from the serial port while writing to the LEDs. SPI is available only on those two pins (11 and 13), so no, it can't be changed to 2 & 3. Not without a total rewrite and a big drop in throughput. Keep in mind that every other Adalight installation is running fine on 11 and 13, so in all likelihood the problem lies somewhere else.

I noticed you're using stranded wires in the Arduino sockets, and there's at least one frayed strand on the data wire. Clean these up and give them a twist, then 'tin' the ends of the strands with some solder if you have an iron.

Move the wires from pins 2 & 3 to 11 & 13, and then comment out this line in strandtest:

Code: Select all

Adafruit_WS2801 strip = Adafruit_WS2801(25, dataPin, clockPin);

Instead, enable this line (just a few lines down), which uses hardware SPI:

Code: Select all

Adafruit_WS2801 strip = Adafruit_WS2801(25);

Make sure 'Uno' is selected as the board type in the Arduino IDE, and upload the sketch. If it works, great, SPI is OK and we'll move ahead with finding the problem in LEDstream. If it doesn't work, we'll need to muck around in the library source, possibly slow down the SPI speed a bit.

[Rads]

Hi burgess, hope your feeling better.

Tried the new settings in strandtest, with soldered cables but still nothing, I can 4.4v on yellow (pin11) but not modulating.

What do you recommend now?

[Rads]

I'm not sure I understadn this one week, one question process.....I've been struggling with this for 4 weeks, following everything as per the instructions and I can only get strandtest to work. I purchased 4 sets of lights so I'm not making a small build here, but it seems like I've wasted my money