Back from a long posting hiatus … The triangles are almost finished. Some of them are missing connectors, and others miss a second Micromatch connector for chaining. Unsurprisingly, when ordering the LEDs from China, we didn’t get APA102 LEDs but some clones: SK9822. It’s a bit different though, but this article sums it up nicely. I had to tweak my LED strip driver but it wasn’t a big deal.
Another surprise: everyone thought that we had 20 triangular PCBs, but no: we found another one. This is good news, especially given Murphy’s law.
Speaking of Murphy’s law, on Friday, we tested a triangle, whose power supply started to smoke … I don’t have any pictures but on Saturday we found out with Alexis that there was solder paste under the inductor of the buck converter, which short-circuited it and fried the IC. Fortunately, after changing the regulator and the inductor, everything works as expected, as far as power supplies are concerned.
However, as for the LEDs, it’s another story. I tested all triangles, and 9 of them don’t work properly: there are dead SK9822s on them, but it’s easy to find where the problem comes from with the testing code I wrote and an oscilloscope as an overkill logic probe. Replacing them should do the trick.
Here’s what the test setup looks like:
There’s a program I wrote on the STM32F7 Discovery board that sends a simple test animation to the triangle. Here’s what it looks like on a good panel:
On defective panels, the white flash at the beginning stops at the failure point.
As to the main board, it’s finished and we’re writing the firmware for it.