How to power max7219 with 8 * 40 LED matrix

[MrMiniBeast]

I would like to be able to use an Arduino Nano to control a matrix of 320 LEDs (8 * 40). I understand that both the arduino and the max7219 need 5v of power, but I'm not sure how to supply it. I was thinking I'd power the arduino separately from the max7219 and use 4 AA rechargable batteries to get 4.8v. However, I'm not sure this will give the correct current to either the max7219 or the arduino.
I would really like the power supply to be as small as possible and it has to be portable.
Thanks for the help.

 

[(*steve*)]

The devices will attempt to draw the current they require. If your batteries are incapable of supplying it the voltage will drop.

Try the 4 batteries. Beware that "just charged" batteries or non-rechargeable batteries may have a terminal voltage higher than 1.25V, leading to your battery pack supplying more than 5V, possibly to the detriment of one or both of the chips. A capacitor may be required to prevent the battery voltage dropping during brief demands for high current. If the current demands for the LEDs cause noise on the power supply, you may need to decouple the power supply to the logic from the LEDs.

320 LEDs at 20mA is over 6A, not what you're going to get for any length of time from AA cells. I hope your average LED current is less than that!

 

[shumifan50]

Have a look at a 2 cell LiPo and use a voltage regulator. Just be aware that you will need a balance charger to charge the LiPo otherwise there is a danger of starting a fire. The benefit of LiPos is that they can supply huge currents, but it is also what makes them dangerous.

 

[MrMiniBeast]

Have a look at a 2 cell LiPo and use a voltage regulator. Just be aware that you will need a balance charger to charge the LiPo otherwise there is a danger of starting a fire. The benefit of LiPos is that they can supply huge currents, but it is also what makes them dangerous.

I've got a li-po that is 2S 7.4V 800mAh that I could use I guess. But how do I hook up the voltage regulator and power each individual board? can you give me an idea of what the schematic would like like?