dot matrix

I bought five of those eBay max7219 8x8 dot matrix kits, it didn't have a datasheet with it but google tells me that it may require up to 2 amps each? Is anyone familiar with these? I should be able to set them up in cascade by connecting one with dout pin to the next with din pin?

ac21 said:

I bought five of those eBay max7219 8x8 dot matrix kits, it didn't have a datasheet with it but google tells me that it may require up to 2 amps each? Is anyone familiar with these? I should be able to set them up in cascade by connecting one with four pin to the next with din pin?

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Reference please?


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2 amp / 64 LED = 31.25 ma per lamp - seems possible but as eclectic says - what have you got?

This is where I read that, its a similar setup.

this is the actual eBay listing

I'm not sure what the question is really. The spec says "up to 2A", so you will need a beefy power supply if you want to light all LEDs at once. Chances are that you don't.

You will need to daisy chain the data wire. However, I suggest you wire each module's power leads directly back to the power source.

It's time to experiment!

The 7219 is multiplexed and the digit (column in this case) drivers have an absolute maximum rating of 500 mA, so it's hard to see how they could get to 2 amps without any additional driver stage.

For the bare LED matrix, that 2 amps is looking a bit suspect when you consider that only one column or row can be powered at one instant in time.

As I mentioned before: It's time to experiment!

I don't have any X2 parts so i was researching the best way to run this on a 20m2 and see pin C.2 and C.1 are labeled kb clk and kb data, i wasn't able to find any info on what this does, or if it would be something i could use?

The kb pins allow you to connect a computer keyboard to your PICAXE. KBIn and KBLED commands. Not suitable for LED matrices!

You can use a software-based SPI routine on the M2-series chips to test your LED matrices but it will flicker a bit due to the slower output bit rate. X2s will give the best performance with the hSPIOut command.

Wells i got a max of 245ma with all leds lit, I ordered some 20x2s also .... and made a dc-dc buck converter that will handle 4amps




when i get the 20x2 i'm going to start with xtech007's code unless someone has a reference to another

Done..

http://youtu.be/NneEjulgzB0

Great job!

Good to see a final product with dual matrixes!
Have you tried more then 2?
Maybe you can post the code so we all can learn !

Hope to hear from you soon!

ac21 Are you there?

It's been bit a while, since this post!
Do you have a final product?
Can you post your code?
Video?

Did you not watch the video?

I ended up using a arduino chip to run them.

If you would like that code I can provide

This tread convinced me to give it a try so I ordered 1 dot matrix module in kit form that I received yesterday
http://www.ebay.ca/itm/221443810162?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
Using Westaust55 tutorial ‘’Getting Started with the MAX7219 Eight Digit 7-Segment LED Driver’’, I was able to address it relatively easily using an 08M2.
The worst part was that I had to create my own character dot generator.
I was able to display characters in a non scrolling and scrolling format.
Even with only one module the scrolling effect is quite neat.
You can see a demo at:
http://youtu.be/ClvZfjDK_5w
I have ordered 2 more modules and i will make another demo when i will receive them.View attachment Working.bas