I got an 8x8 LED Matrix from this link on ebay. I'm having a strange problem. When I uploaded a code (link) to my AVR board using Arduino Uno R3 as ISP, everything seems fine but the matrix was holding some unnecessary pixels. I uploaded a video to Filefactory. This file will be available for 90 days only. Please have a look at it. This kit came assembled. I soldered it. Got a short between IC pin 3-4, 8-9, 18-19, 20-21 and DOUT and CLK (output port). Manually fixed it by removing extra solders but pin 3-4 is a little bit difficult to fix. Sometimes a short is detected but fixing it seems okay but the problem remains, then checikg it again detcts a short. However last time I checked there was no short. But after a few minutes the problem again appeared. Any solution?
Video not accessible.
Ergo no suggestions.
Sorry for that inconvenience. I uploaded the same video to youtube. Here it is.
Sorry again, in the previous post I said the kit came assembled but this was just a typo. Actually it came non-assembled DIY kit. Any suggestion will be very helpful.
Very curious.
Certainly not a software problem; either there is still a short in the wiring somewhere, or the MAX7219 is damaged.
Get another kit!
You have a short somewhere. Work out whether the line of LEDs is a row or column and trace from the appropriate max7219 pin.
I checked all the traces from the max7219 pins to the matrix. Here is the diagram for that dumb a** Chinese matrix. Mine has exactly the same connections. They merely copied sparkfun and produced an inferior quality module. Alas, we can't buy genuine sparkfun products in India. Indian market is inflated with all types of inferior quality spurious Chinese products. Even our government is not getting a regular way tax from these copy-cat unbranded products. Politicians are not doing anything because they are busy with internal conflicts.
Last time I checked my board pulling out the max7219 and the matrix, but did not find a short. Actually I have a very poor know how of soldering. I soldered the kit with a ton of solders left on the pads then removed the extra solders with a de-soldering pump, when I detected repeated short circuits. Now, there is no short circuits, at least it appears to be so. But my daddy is guessing some solders are getting overlapped between pin 3-4 when the module is connected for a while and the temperature rises that I cannot sense with a bare hand. May be true. I already gave up hope.
Very curious.
Certainly not a software problem; either there is still a short in the wiring somewhere, or the MAX7219 is damaged.
Get another kit!
Considering 1 USD = 64.36/- Indian Rupees (INR) as on today, and this rises regularly based on inflations, guess what it would take to invest 3.418 Dollar for another kit. Since the kit is not completely damaged and I will not install this module to anywhere, I planned not to invest any further on that Chinese bast**d.
Thank you all for the time you invested and helped me. From your help I got a homely feeling that money can't buy.
Thanks again.
I have a lot of the copy modules and they all work ok. All of them are derived from the basic circuit given in the datasheet. If there is a problem with the one you have then it is just bad luck.
Make sure if you are checking for shorts that you are using a magnifying lens of some sort. Shorts are not always obvious until they are made much bigger...
Pinaki_Gupta_1982:
Indian market is inflated with all types of inferior quality spurious Chinese products. Even our government is not getting a regular way tax from these copy-cat unbranded products. Politicians are not doing anything because they are busy with internal conflicts.
I do hope you do not imagine any of those factors are in any way unique to India! 