Yes that feature seems to be available without much extra cost your right.

My next question would be can a nano handle an RTC DS1307 at the same time as an -nRF24L01+? or is there a limitation of some sorts in terms of them using similar communication resources from the nano?

@tbowmo
Thats very interesting that the uno is essentially a larger version of the nano thanks for pointing that out.

Why is it that A6/A7 are only allowed to be input only?

@BulldogLowell
I want to keep the additonal hardware to a minimum but thank you for pointing that out ive always wondered how to get more IO when your limited,

Im also wondering if there are any special features I need to look for in my relay boards in order to control 12V DC solenoid valves, I know for motors and such you oftne need some kind of kickback protection. Do I need features such as optoisolation when using my 12V DC solenoid valves?

Hello all,

Im currently going through my options for a project in which I want to use the following to create essentially a cost effective ecosystem controller.

Digital pin use (12/12)
-7 relays to control
Light source
Heater
Water pump
3x Solenoid valve
PC fan
-1 rgb led
-nRF24L01+

Analog pin use (3/8)
-temperature sensor
-humidity sensor
-water level sensor

A few questions.

1. From my rough estimate of pinusage I seem to have enough just using the arduino nano which is what I want. I have plenty of analog pins left and im a bit confused as to why it says there are 14 digital pins but really only 12 when I count them, do TX and RX count as usable digital pins?

2.While you normally see Arduino unos or megas being used for this sort of thing, im wondering if there is some sort of limitation im overlooking if I was to use an Arduino nano.

3. If you can see some huge reason why the nano is underpowered to basically poll a few sensors and activate relays please point it out.

Still in the early stages of planning but would appreciate any input from the battle hardened people here.