connecting two Arduinos to add extra inputs

Hi All,

Does anyone know if it’s possible to connect two Arduinos (Lilypad in my current project) in order to add more inputs? I would imagine controlling everything from one “master” Arduino, while the other one just passes them along to its inputs.


It’s possible, but you may find it easier to expand the number of inputs with a multiplexer (analog) or a shoft register (digital). Roughly how many inputs do you need? And do you need analog or digital?

I would ideally like to have 28 digital inputs, while the Lilypad only has 13. Since I’m making a wearable, I have certain constraints as far as bulk and wiring. For instance, I decided not to use shift registers because of bulk and the need to have PCBs fabricated. I also decided not to use charlieplexing because the wiring would be too convoluted for a circular configuration of LEDs.

Open “Examples” in the IDE and have a look at Library - Wire Master/Slave Reader/Writer sketches.