How to figure out schematic of 8x8 LED matrix?

I don't have a datasheet for the bicolor LED matrix that I got on eBay.
It has 24 (12x12) pins, but no way for me to tell which one is pin 1.
Any clues? :)

Picture of How to figure out schematic of 8x8 LED matrix?
20121002_094348.jpg
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frollard4 years ago
Normally bicolour led matricies have
http://oomlout.com/DATASHEETS/LED-8X8M-03.pdf

both leds in series, 8 rows and 16 columns = 24 pins.


As for pin 1, look around for a square dip trace on the back of the board, there MUST be something to indicate pin 1.

bratan (author)  frollard4 years ago
Thank you! Still unsure tho, how to trace it :( There's absolutely no indication of Pin1. I took some pictures, maybe it will help? :) I attached marked piece of foam to right most pin under the lettering.
I've tried to trace pins by applying power via resistor, and mapped some of the dots, but for all I know I might have this thing upside down and not know it :(
Any tips for finding out Pin1?
One thing I figured out for sure is that LED rows are parallel to the pin rows, and that helps! :)
So far I have this idea:
If Pin1 is one of the pins on ends I have about 1 in 8 chances to figure it out (1 in 4 but it might be either cathode or anode so...). So my plan is:
1. I will choose a dot I want to light up (i.e. Red, Row 5, Column 4)
2. Choose one of the 5 corner pins and connect it to the ground.
3. Try connecting all other pins to +5V via a resistor until LED from step 1 is lit.
4. If none get lit, connect that corner pin to +5V via resistor and probe all other pins to Ground.
5. Continue 1-5 for 3 remaining corner pins.
Does my logic make sense?
20121002_094329.jpg20121002_094348.jpg
frollard bratan4 years ago
So, top picture showing the JX serial number

With that facing you, the row along that side SHOULD be pins 1-12 going left to right closest to the black text. The other row runs right to left counting 13-24.

Try jabbing around based on the datasheet like thatand see if that helps.
bratan (author)  frollard4 years ago
Well I finally figured it out. That is I had to create my own "data sheet", because one from Sure LED didn't fit at all...
I marked pin under "HG" letters as Pin1 and went from there.
4 leftmost pins (12,11,19,9 and 13, 14, 15,16) are common anodes.
1 thru 8 are Green LED cathode, and 17 thru 24 are Red LED cathodes. Going from there I made a table and eventually changed pins on the image from Datasheet. And finally came up with this. Row closes to the black letters is row 8, and left most column is column 1.
LED_matrix_pinout(JX-1588BHG).png
bratan (author)  frollard4 years ago
Thanks man! Unfortunately it didn't work :( That pin on the left of the lettering is actually anode, so it can't be pin1.
Either Pin1 is not in the corner or Datasheet that I'm using is incorrect for this model. According to datasheet PIN1 controls all Green lights in 5th Column. I tried all 4 corner pins and none of them lights anything close to 5th column... Crap, I guess I'll have to write diagram for it from scratch, oh well :)
bratan (author)  bratan4 years ago
I wish there was EDIT option... I wanted to say that in Step1 I will choose LED that connected to PIN1 on the oomlout DataSheet (provided that Datasheet is correct)...
quote from a sparkfun comment:

"If you look at the bottom, there are pin numberes in the epoxy. rule of them, if you hold the display so the black model number on the side is facing down, then pin 1 will be bottom left, but hold it upside down and look for yourself (I’m going off the Sure Electronics LE-MM103 displays)"
dancopy2 years ago

Would that be?

Matrix Bicolor.jpg
dude i am new to programming with microcontrollers can you help me how to program with picaxe 18 m
bratan (author)  avinash reddy4 years ago
Forget PIC if are new! Get Arduino, it's very user friendly.