Hello:
I need to control 70 leds. One at a time.
Can you help me? what materials do I need for this?
thank you very much.
5 x "4 TO 16 LINE DECODER/DEMULTIPLEXERr" like the 74154 (80 pins)
1 x "3 TO 8 LINE DECODER" like the 74138 (to enable one of the 5 16-bit decoders)
7 data pins to address the two levels of selector.
If you hook a PWM line to one of the gate inputs on the 74154's you can fade each LED in and out.
Or an 8x8 matrix driver chip and an 8-bit shift register for the last few LEDs.
Or a 5x7 matrix driver chip like the MAX6953, can do 4 x 35 LEDs.
Thank you very much.
Have you or know any good tutorial to do this?.
or 2x M5451 chips - can drive 35 LEDs each.
The CC-Shield uses two of them so you could use the code from that as a starting point:
If you go to www.arduino.cc, select Learning, search for 8x8 matrix, you will find some links.
This is one of them
http://www.arduino.cc/playground/Main/DirectDriveLEDMatrix
To me there should be current limiting resistors in there somewhere.
Instead of arduino pins, you could drive with shift registers, etc. as discussed above.