Defective DotStar Matrix
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Defective DotStar Matrix

by friponneau on Mon Feb 05, 2018 5:26 pm

This email is about the following products:
    1 x Flexible Adafruit DotStar Matrix 8x32 - 256 RGB LED Pixels[ID:2736] = $99.95
    1 x Flexible Adafruit DotStar Matrix 16x16 - 256 RGB LED Pixels[ID:2735] = $99.95
Order#: 1666596-4918023839
Ordered on Jan 31st, received last week.

With this order, I also bought those:
    1 x Adafruit DotStar Digital LED Strip - White 60 LED - Per Meter (WHITE) [ID:2240] = $119.80
    1 x DotStar RGB LED Disk - 240mm diameter[ID:2477] = $134.95
I tested the new units I received with an older Arduino project that already works with an (previously bought) 8x8 DotStar Matrix and runs the "Adafruit DotStar strandtest". Basically, the test is simple: replace the number of LEDs in the source code, unplug the previous DotStar that's already there (I use the standard connectors that come with the unit), plug the connectors to the new DotStar unit, check the + & - & DIN & CIN are actually in the right position (Strip and Matrix Data & Control wires are actually inverted, no biggie), plug in the power supply for the Arduino & LED unit, upload the program and watch the show. I had no problem with my new LED Disk (255 LEDs) and the 4-meter strip (240 LEDs) which both work fine. Unfortunately, I could not make either of my new DotStar Matrix (256 LEDs) light up.

I wired-in an amp meter to get an idea of what was happening and I got some strange readings: instead of the usual ~0.46 amp I get when I run the test with the other DotStar products, the 16x16 Matrix reading was off the chart as if there was some kind of shortcut somewhere (disconnected the power in a hurry), and the 8x32 Matrix reading was around 11 amp, way too high. In both cases no LEDs did actually light-up during the test-- not even a little "flash".

What should I do to exchange the units?


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Joined: Thu Jan 21, 2016 4:28 pm

Re: Defective DotStar Matrix

by franklin97355 on Mon Feb 05, 2018 8:18 pm

Could you post large, clear, detailed pictures of both sides of your board and the connections to it? Pictures should be less than 1meg in size.

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Re: Defective DotStar Matrix

by friponneau on Mon Feb 12, 2018 12:02 am

Aaargh, no need, I found the problem.

It appears that the wiring on the LED products (disks, matrices, strips) is literally random, even across similar products (two LED matrices for example might have completely different wirings, different from a strip, and from a disk).

Here's how deep I've seen this rabbit hole go:
    - Male/female connectors can be either in or out (this is barely annoying though)
    - Signal order within the connector follows the day's special. For example: the "second wire from the right" isn't always the same thing; a bit more annoying, but spotted easily enough.
    - Wire color coding is according to the chef's choice. For example, a "red" (or "green") wire can be soldered to anything. Now I admit this one went below my radar, and was my downfall. Result: a 100$ lesson. :(
Live and learn, they say...

Suggestion: It might be a good idea to carefully pry the soldering iron from the hand of the artist who's currently doing the work, replace it with a rainbow-coloured lollypop, and ship those expensive LED boards with the unsoldered connectors in the package, so they can be installed properly... Or at least give the option, so people desiring randomly-generated connectors could still get them.

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Joined: Thu Jan 21, 2016 4:28 pm

Re: Defective DotStar Matrix

by embedgeek on Fri Jun 22, 2018 3:06 pm

So, are these worth ordering:


I was going to place an order for three of them, but it's not worth the headache if they are defective.

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Joined: Wed Sep 10, 2014 2:42 pm

Re: Defective DotStar Matrix

by coyote20000 on Sun Jun 24, 2018 2:57 am

I think what Frip is saying is that you have to pay attention to the labels on the board rather than rely on wire color or pin order cause every device could be wired different...

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Joined: Sun Jan 12, 2014 2:59 pm

Please be positive and constructive with your questions and comments.