How much can I run off of one Uno

Hi all,

I just have a quick question

can I run
4 74hc595
2 8x5 LED matrix's
4 buttons

off an Arduino Uno

depends how you wire them up but yes, its conceivable you can.

Im just wondering the draw off of one pin can handle all but the buttons

You can't run all that of a single pin. It's nothing to do with current draw, it's logically not practical.


so make it like 5 pins then

  1. GND

To interface with 595 shirt regs you need


Plus of course the power.

As for the LED matrixes, they will be hung off the 595 will they?


yes thats the Idea so should i run transistors?

595s aren't realy designed to drive LEDs so you can use transistors or driver chips (both with resistors).

Alternatively on of the SRs with drivers and curent limiting built in like the TLC5916.


so something like this?

Doesn't that tool make real schematics? That's like looking at a bunch of coloring on a restaraunt place mat.

If you're needing to drive higher currents for LEDs, look at tpic6b595's. shift register with high current capability.

Yeah sorry marshen, it's impossible to follow those fritzing diagrams especially with no pin names.


so something like this?

Can you name the software you used to do that ?

Most people use Eagle, personally I think it so hard to use it will put you off for life. I used to use TinyCad and that was quite nice.


I agree. I'm still much put off by the Eagle "way" since I'm more about "quick" and "easy".

I settled on Abacom SPLAN/Sprint Layout solution.

Example: (I figured I can show you that you can attach a lot to the Arduino)

I use the software from expresspcb. easy to use, quick to figure out. Easy to make up symbols, for example here are some I made for a generic arduino, a ProMini, a couple of shift registers, and an RF Rx/Tx pair.
I was using Eagle last night to try and create a quad flat pack arduino clone (like a promini but smaller) and it was a struggle, there are like a gazillion library compontents to go thru, I have still to find a small resistor to put in, may have to fake it somehow with just a couple of holes.

can those software do schematics for pelleted plates ? (... I used google translate to get this word, not sure about it as a consequence ! sorry)
I'm done with my tests on solderless matrix and I want to move to the next step: do it on a pelleted plate.
It's a tiny circuit but I'd rather plan it ahead and make my idea on a software.

Yes, the different software packages can create the printed circuit board design. You would then make your own circuit board (there are lots of examples of this on the web), or have a company make it for you.
Here is an example from express PCB of a standalone board I am thinking about, with extra holes for mounting some extra parts. I made all the connections on the top layer, and the bottom is nothing but ground connections. I made two copies and just added the extra holes for now. will make you 3 boards this size for $51 USD and ship to France for example for $50. There are many other companies also.


well, actually I was not thinking about the PCB. I was thinking about those boards that have a complete grid of holes and each hole has a copper pellet (some boards have the other side with conductive material for the ground on the complete surface).
then you solder your componants to the copper pellets and the copper pellets together by yourself. and if the pellets to connect together are too far you can just use a piece of wire.
... sorry I don't know the exact name of those in english.

let me find a picture. here you go !

Those are proto boards, prototyping boards, breadboards, a handful of names they go by. There is also perf board, but this generally refers to board that do not have any copper pads on them, just the holes to mount components on.

ah ok ! I thought the proto board was the white ones (usually) where you just plug in your componants and you don't need to solder.
anyway, thanks for the word :slight_smile:

... so my question was about finding a software to convert a normal circuit to one that can be implemented on a proto board so I can optimise space and how are componants organised, plan the circuit, make sure I don't need to solder too many [ugly] wires, etc.

I don't want too much wire to put ... and then I can post a nice jpg of the circuit on the forum afterwards ... etc.

any hint ? :slight_smile: