Driving 32 Led without multiplexing

Hi,

Im doing a DIY proyect and i would like to keep it as simple as possible. I need to drive 32 (20mA) leds in a line. Not a matrix. I have read that the max power of the Arduino Mega is 200mA global, so im way over it as they will be all turned on at some point.

Is there an IC that could get 32 inputs from the arduino and output them without the limited power of the motherboard?

I'm a noob, and even with all i read about multiplexing it seems to be too much for me.

Thanks in advance

h1p3rcub3: even with all I read about multiplexing it seems to be too much for me.

Ah, but that is where you are dead wrong!

The solution is - don't do the multiplexing yourself. Get a MAX7219 and let it do it for you. You just shift the data into its registers and it magically appears on the LEDs to match. Get one of these dirt cheap boards (actually, no get two or three kits): |500x500 Start by assembling it fully and learning to write to the registers and make LED patterns. Then get another, assemble it except for the matrix sockets and wire your LEDs to the points that mount the matrix, arranging them as you need in a line or otherwise. Basically, you have a common cathode line for each group of eight, and the anodes then wire to the matching LEDs in the next group of eight and so on. It is actually easier to wire this way as you have only fifteen (for 32 LEDs or sixteen for 64 LEDs) wires from the board to all the LEDs, rather than 33 or 65. And you only have one resistor instead of one for each and every LED.

My strong advice - buy the board(s), experiment with them, then build them into your project.

I offer a MAX7219 breakout board that lets you connect LEDs individually. Easy to connect LEDs via 30 AWG wirewrap wire to male headers plugged in where the LEDs are connected (I posted a pic of that somewhere in the forum) http://www.crossroadsfencing.com/BobuinoRev17/ |500x374

h1p3rcub3: Im doing a DIY proyect and i would like to keep it as simple as possible. I need to drive 32 (20mA) leds in a line. Not a matrix. I have read that the max power of the Arduino Mega is 200mA global, so im way over it as they will be all turned on at some point.

You can drive up to 1000 pieces of WS2812 RGB LEDs with just one single Arduino output pin.

No extra hardware required, except a 5V power Adapter, and perhaps a 470 Ohm safety resistor. At maximum intensity, 32 WS2812 will draw 32*60mA = ca. 2 Ampere maximum current.

I have read that the max power of the Arduino Mega is 200mA global

I have corrected this over & over - 4 Vcc pins, each capable of 200mA, so 800mA total. Direct information from Atmel: http://forum.arduino.cc/index.php/topic,161354.new.html Current must be spread over the ports per notes 3. and 4. of Table 31.1 DC Characteristics

if you want something easy and quick, get some ULN2003 or ULN2008, these things help you drive motors with microcontrollers

http://www.botskool.com/sites/default/files/image/smcuu1.jpg

Dan_Kato: if you want something easy and quick, get some ULN2003 or ULN2008, these things help you drive motors with microcontrollers

Unfortunately, they do a very poor job, especially at 5 V.

They are Darlington devices, which means that they automatically lose at least a Volt when switched on. At 5 V this is a major problem, at 12 V it is not so bad but means they are going to get warm if you draw any significant total current.

If used for multiplexing, it is even worse, as you have both cathode and anode drivers, and if your cathode drivers are losing voltage and the anode drivers as well, you lose a lot of your voltage. The ULN200x drivers should be considered as obsolete.

If you intend to use them driven by a shift register, then it is vastly superior to use a TPIC6B595 (or the "A" version) which implements the shift register and also contains properly rated FET drivers which drop a very low voltage when switched on.