I would like to build a 8x8 (or bigger) LED Matrix by my own. The LED Matrix should be controlled by an Arduino Diecimila.
I have seen similar Examples using the shift registers 74HC595.
As I can See there is a maximum Output Current about 70mA:
For my purposes I need bright LED's with forward current at least 20mA, 35mA or higher. That means more than the 74HC595 does support.
Does anybody has an idea how to control and build my LED Matrix, or maybe know a Tutorial that would help?
This device TPIC6B595 suport max 150 mA.
ID Continuous drain current, each output, all outputs ON, TC = 25°C(4) 0 150 mA
Have you considered making the matrix using WS2812b addressable strips? The big advantage to using them is that unlike a scanning matrix there is no need to constantly be refreshing the matrix if nothing changes.
No this is an absolute limit not an actual limit. You missed the disclaimer underneath that table.
Most 5mm LEDs have a maximum of around 20 to 30mA and would be destroyed by 35mA or higher. Please post a link to the datasheet(s) for the LEDs you are considering to use.
Question: when you say you need the LEDs to be bright with at least 20mA current, is that because you have tested them with 20mA continuous current and less than that will not be bright enough?
The reason I ask is that normally in a matrix, the current is not continuous. A matrix is usually multiplexed: only one row or column is lit at any instant.
In an 8x8 matrix, any individual led will only be lit for 12.5% of the time. So even if the current flowing through it is 20mA when it is lit, the average current will only be 2.5mA. The brightness will appear the same as an individual led with 2.5mA continuous current, so much less bright than you need.
In an 8x8 matrix, to achieve brightness equal to 20mA continuous current, the actual current will need to be 160mA. Most LEDs would be destroyed.
One solution could be to have your LEDs arranged physically as a matrix but not electrically a matrix. The ws2812 idea suggested by @Grumpy_Mike is one way. Or 8x tpic6c595 shift registers suggested by @ruilviana is another.
This is the proverbial one I made earlier. It is in an IKIA glass fronted picture frame, hence the plastic rapping on the outside.
May or may not be useful to you
Definitely need to see the data sheet for the LED. A lot of LEDs have a "peak forward current" rating for multiplexing applications that is substantially higher than the maximum continuous current, but has specific limitations on duration and duty cycle. You do need to be careful when driving LEDs at high current, if the multiplexing stops for any reason the LEDs can quickly overhead and be destroyed.
The MAX7219 or MAX7221 is what you need.
Current up to 40mA.
Control 64 individual LED.
Another excellent suggestion, but may be unsuitable depending on the answer to the questions I put to @cvconnector.
40mA is the peak current but the average current will be only 5mA, so not as bright as 20mA which is the minimum that @cvconnector says is needed.
As far as I understand using these addressable strips does not work for my needs. I have to put everey Single LED into a seperate little Box for an Art Installation.
In which case you can get these addressable LEDs in a single package.
Do you know the spacing of the boxes? WS2812 come in "LED/METER" spacing of 30/m, 60/m, 144/m... and the "IP" value of some of the lower LED/m are flexible so you can move the LEDs closer by flexing the cable.
I have tested it with an white LED angle: 25degree, lv: 10600mcd If: 20mA, Uf: 3,2V
And it could be even brigther.
No, that is not the way single LEDs work. Look up is not the way it works.
Search for WS2812 5mm package.
It is true however you will not get more current than 60mA per LED, or 20mA for a single colour.
O rly?
Read my previous post before you start to criticize. It seems like you have little idea about what is available on the market.
The APA-106 uses the same protocol as WS2812BLEDs, making it compatible with libraries designed for NeoPixels and similar addressable LEDs.
Something like these ones? https://www.berrybase.at/adressierbare-ws2812-rgb-led-pth-8mm-diffus-5er-pack
If you need true white then the addressable RGB LEDs might not be a good solution.
