Hi everyone, currently I´m developing a project where a portable solution is needed. An arduino nano is used along the NRF24l01 module as transreceiver, KY-040 encoder and a single white LED. I have some questions related to powering this project.
1.- AAx4 batteries (eneloop) should be enough considering the 4.8v aprox. provided? I read in the forum this is possible but the specification says 7-12v for input voltage. Am I misunderstanding something?
2.- Considering the specified power source. Can I power the nano board through the 5v pin?
3.- The mentioned batteries have around 2000mAh (8000mAh in total). Considering the components should I expect a duration to be 12hrs+?
Sorry if the questions may sound obvious but I´m new at this.
When you power a Uno/Nano/Mega/etc. there are several options.
if you plug in the USB cable, your PC provides the +5V directly.
if you plug a power cable into the power jack or bare wires into Vin, that goes to an onboard voltage regulator that provides +5V to the board. The voltage regulator needs a bit of "head room" above +5V to function, so the spec is 7-12V.
If you plug a bare wire into +5V, this goes directly to the board like the USB cable so it has to +5V
For portable projects, it is best to provide the +5V on the 5v pin. If you have a battery above +5V and power the board through the Vin pin, you loose power through the voltage regulator
The 5v Nano should work fine on 4.5v provided by 3 x AA Alkaline cells or the 4.8v provided by 4 x AA NiMh cells.
Be aware that the nRF24 needs 3.3v (max 3.6v). And it may not run reliably from the 3,3v pin on a Nano.
I have built my standalone projects using an Atmega 328 running at 8MHz and mounted on a piece of stripboard. I power them with 2 x AA alkaline cells (3v) which also suits the nRF24 very nicely.
I can't recall if it is possible to buy a 3.3v version of a Nano.
dsk128:
1.- AAx4 batteries (eneloop) should be enough considering the 4.8v aprox. provided? I read in the forum this is possible but the specification says 7-12v for input voltage. Am I misunderstanding something?
2.- Considering the specified power source. Can I power the nano board through the 5v pin?
3.- The mentioned batteries have around 2000mAh (8000mAh in total). Considering the components should I expect a duration to be 12hrs+?
Pelase note that in 1 you mentioned 4 batteries giving 4.8 volts meaning you have hooked them in series giving you 4.8 volts at 2000 mAh.
In 3 you mentioned 2000 mAh (8000 mAh total) which you only get if the batteries run in parallel (1.2 volts 8000mAh)
As to how long your project will run, that depends on your current of total items.
Eg. NANO @ 100% use
Tranciever @ 80% RX and 20% TX use
LED @ 50% use
Which you can not work out from the info supplied.
Robin2:
I can't recall if it is possible to buy a 3.3v version of a Nano.
I don't think you can, as it features power by USB cable. The Pro Mini doesn't, but is otherwise much the same thing, and comes 5v or 3.3v. I imagine the 3.3v Pro Mini is an ideal partner for the NRF24.