Hi all,
I'm creating a project that uses 6 RFID readers in one room feeding to 6 arduino in another. instead of running a 3.3V wire for each rfid reader, am I able to create a 3.3V bus from all arduino's and send one wire to the readers?
It seems like it should be OK but I'm not an expert and wanted to make sure before I released the smoke.
The Arduino can supply only about 100 mA of current on the 3.3V, maybe less - check the specs. It's meant to help you easily connect 3.3V sensors, which normally take just a few mA. The same accounts for your RFID readers: check the specs.
Make sure that the total peak current drawn by these readers is comfortably below the maximum current the 3.3V regulator can supply.
If you are asking can you parallel the 3.3v supplies from multiple Arduino regulators, in general this is not advisable. You can't really guarantee each 3.3v supply will contribute equally to the combined load. If your total load is significantly less than the 600mA theoretical supply from the six regulators, it might work. Long runs of 3.3v logic data signals can also be tricky as these long runs can introduce significant noise to the input pins. You might want to just consider relocating the controllers closer to their RFID readers.