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Topic: Cheap LED Matrix (Read 2 times) previous topic - next topic

coco3431

I am new to the forum and I want to make a clock with and arduino and an led matrix. I wanted to make the following and change the code:
http://makeprojects.com/Project/PS-2-You+LED+Sign/1069/1#.UOhbMG8bSSo
but it seems that Sure Electronics dosent sell the led matrix anymore. I looked at adafruit.com and came across the following:
https://www.adafruit.com/products/872
but it is more expensive and it is small for a wall clock. Can anyone assist me in what I need or where I can get one of these cheaply.

Grumpy_Mike


coco3431


Is this one big enough for you?
http://www.evilmadscientist.com/2007/led-matrix-displays/


This would be great, perfect size and reasonable price. My only question is how many pins would I need to control this matrix and could I use some kind of a chip to decrease the pins needed without much work.

CrossRoads

Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

coco3431


The MAX6953 can control 4 of those 5x7 displays using just 2 IO pins, SCL & SDA

http://www.maximintegrated.com/datasheet/index.mvp/id/3291?ver=F&utm_expid=50713806-2&utm_referrer=http%3A%2F%2Fwww.maximintegrated.com%2Fpst%2Frun.mvp%3Fq%3Dmax6953%26image.x%3D19%26image.y%3D12



Is there anything cheaper? Maybe it could only control one display would be ok. I cant really imagine spending $25 on a chip that ill probably solder wrong and it does not really look like it would go in a breadboard.

Grumpy_Mike

Quote
Is there anything cheaper?

Same thing on ebay?

How about the MAX7219?

coco3431


How about the MAX7219?


This is a perfect price. I like the led matrixs mentioned earlier but could anyone point me to cheaper ones?

LarryD

The way you have it in your schematic isn't the same as how you have it wired up!

coco3431

Will the MAX7219 work with this matrix I found on ebay?
http://www.ebay.com/itm/150961254444?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

The only reason I would ask is that the chip says common cathode and the matrix says common anode. My strong point is programming not circuits.

LarryD

The MAX7219/MAX7221 are compact, serial input/output
common-cathode display drivers...

http://datasheets.maximintegrated.com/en/ds/MAX7219-MAX7221.pdf
The way you have it in your schematic isn't the same as how you have it wired up!

coco3431


The MAX7219/MAX7221 are compact, serial input/output
common-cathode display drivers...

http://datasheets.maximintegrated.com/en/ds/MAX7219-MAX7221.pdf


Thanks, wow my searching skills are sure lacking today. Ill keep looking thanks for everyone's help. Just one last question does anyone have a good beginner (or advanced) circuit book that they could recommend?

LarryD

The way you have it in your schematic isn't the same as how you have it wired up!

CrossRoads

MAX7219 is $1.25 here
http://www.dipmicro.com/store/PCB-UNI30H
hard to get much less

$25 is nuts - go to maxim-ic.com and request a sample in DIP footprint. The part works very nice.

There is no difference between common cathode & common anode:
Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

coco3431


What is a BOOK?

http://www.electronics-tutorials.ws/index.html


I think this is going to be my book. Thanks!


$25 is nuts - go to maxim-ic.com and request a sample in DIP footprint. The part works very nice.


This looks great, a free sample is way better than $25.


There is no difference between common cathode & common anode:


Could someone else please clarify this, there is two different answers now.

CrossRoads

Look at the 8x8 matrix - one is billed as common anode, one as common cathode - which is which?  In both cases, the rows are connected to anodes, and the columns connected to cathodes.

For non-square configurations, like 5x7, you'd want to make sure the 5 anodes made up your rows (driven by the Segment pins), or the 7 anodes if wanted taller rows, with each column having a common cathode (each column driven by a digit pin).
Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

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