Guidance on big Arduino project

Hello all,
I apologise if this queries have been answered alredy in other posts.. but trust me I did not find really one.

I am starting a massive arduino project and was wondering how far I can push the board in terms of expandibility and control.
To implement all the functionalities I plan (current release, next could need more :slight_smile: ) the system should manage around 30 sensors (temperature, presence, etc), but should host as well 7 shields (RTC, SOLAR, GSM/GPRS, WIFI, MP3, RADIO, MUX?, Other?) to grant all functionalities.

My queries:

  • is there a limit to the number of shields that a single arduino board can host?
  • Are there any known challenges (CPU performance is under control :wink: ) from a circuit perspective I should take care of?

Limit on shields is signal overlap and amount of current being used if they are powered from Vin/5V/3.3V.
Signal overlap a problem especially with SPI if multiple cards all want to use D4 or D10 for slave select.
Current draw - reverse polarity protection diode is good for an amp, 5V regulator for 800mA depeding on voltage level of Vin, 3.3V only good for 100-150mA.

Current draw - reverse polarity protection diode is good for an amp, 5V regulator for 800mA depeding on voltage level of Vin, 3.3V only good for 100-150mA.

And only 50ma of 3.3v if board is based on using FTDI internal 3.3v regulator rather then standalone 3.3v regulator used sense release of Uno and 2560 mega board designs.

Lefty

Thanks everyone, that is useful ... will run some tests and eventually split the workload between a UNO and a Mega.
Will update :slight_smile:
Cheers