Hello, I am in need of more pins than the Arduino Pro Mini has, and one solution I found was to use a shift register. Instead of buying actual shift registers, which I currently don't have, is it possible to use multiple Arduino boards to "extend" the range of pins available? I need about 27 total pins to be exact. I have some Pro Mini boards that have specific burned pins, but would work great as extenders, assuming that is even possible? If so, how could I achieve this extension of pins?
Hopefully, the bad pins aren't the I2C pins.
It is surely possible. But you need to write the code for the "shift register" Arduino. When you are doing this you may make it much more clever than a dumb shift register. I.e. the main Arduino may command the other Arduino to generate a PWM signal. Also you may offload some work to the other Arduino. It depends on your application.
Smajdalf:
It is surely possible. But you need to write the code for the "shift register" Arduino. When you are doing this you may make it much more clever than a dumb shift register. I.e. the main Arduino may command the other Arduino to generate a PWM signal. Also you may offload some work to the other Arduino. It depends on your application.
It's mainly to control a bunch of LED lights in a specific order. I found something about master / slave capabilities, which is what I think AWOL was referring to about the I2C pins, but sadly there are hardly any good tutorials, especially on the coding portion.
This should be easy. Use any way for two Arduino's to communicate (I believe there will be plenty of tutorials for this) and let one Arduino to say the other one what to do. The communication may happen over I2C, SPI or software Serial. To keep it simple your protocol may be as simple as Arduino A sending a byte to Arduino B and the byte says which pin should be modified and what action to take.
It is possible to write an Arduino program so the Arduino behaves exactly as a (slow) shift register. To do so you need to understand well how the shift register works. But I think it is unnecessary complicated.
I would caution against using arduinos with burned pins - often those pins have both the high and low drivers "stuck on", and further failures may result later. Pro mini clones are like $2 each, just pitch the damaged ones.
Smajdalf:
This should be easy. Use any way for two Arduino's to communicate (I believe there will be plenty of tutorials for this) and let one Arduino to say the other one what to do. The communication may happen over I2C, SPI or software Serial. To keep it simple your protocol may be as simple as Arduino A sending a byte to Arduino B and the byte says which pin should be modified and what action to take.It is possible to write an Arduino program so the Arduino behaves exactly as a (slow) shift register. To do so you need to understand well how the shift register works. But I think it is unnecessary complicated.
I'll look into it, thanks!
DrAzzy:
I would caution against using arduinos with burned pins - often those pins have both the high and low drivers "stuck on", and further failures may result later. Pro mini clones are like $2 each, just pitch the damaged ones.
Thanks for the heads-up.