how to get 100 digital pins ?

  • how to get 100 digital pins
  • how to merge boards

thanks :slight_smile:

samir_assaad:

  • how to get 100 digital pins

IO expanders or shift registers.

samir_assaad:

  • how to merge boards

With a big hammer, or by linking them together through a serial bus system, such as I2C, SPI, etc.

how to use (IO expanders or shift registers.)
if you have tutorial
thanks

Try this:
Outputs

Inputs

Don't know what you mean merge boards.

  • Is this way can I control led - led ?
    i mean i need to make switch on/off for 100 pins (led)

thanks

Yes, if you write the code to do so.
You need a power supply to handle 100 LEDs .

One way - use two MAX7219. Can use two of these boards and an Uno. The LEDs are multiplexed, turned in groups of 8.
Or use shift registers, with no multiplexing. This board drives 96 LEDs, can use spare IO pins for the last 4. Arduino function is provided by the '328P, and offboard FTDI adapter is used to download code into the board.
http://www.crossroadsfencing.com/BobuinoRev17/


I'll have to get one of those boards.

new board Crossroads ?

Yes, posted word about it fairly recently.
Here's the schematic and a demo of some lights flashing.
http://www.crossroadsfencing.com/BobuinoRev17/MAX7219demo_movie.AVI

hi crossroads ,
im from lebanon , The country does not let anyone to enter the electronic unless he has a license from the company. I do not have any license will remain the board on the airport.
thanks

samir_assaad:

  • how to get 100 digital pins
  • how to merge boards

thanks :slight_smile:

better use I2C

I've used six [u]MAX6978[/u] chips to control 48 LEDs. These are specialized LED driver shift registers. You can daisy-chain these together to control as many LEDs as you like with only 3 Arduino outputs. They also make a 16-port version.

A "regular" shift register chip can be used the same way except you need current-limiting resistors in series with each LED.

Doesn't matter what we suggest if the government/customs won't let electronics into the country; anything would need to be ordered by a qualified middle man.