LowPowerLab Forum

Remote Status Sensing Overview:
Range – Approx 50 Ft from street to an underground fiberglass vault about 4 FT below grade.
Moteino with  radio is in sleep mode (min possible power usage) until contact closure (dig input) occurs.
Moteino with radio senses a momentary contact closure and turns radio on.  It transmits a status message, after a 15 min delay, every 15 seconds ( info is the Moteino I.D. and which input based on the contact closure changed states).
Moteino in the vault will keep sending this message for 2 hours or until reset by the receiving Modeino.

I am new to using Moteino products.

Some questions I have:
What is the best radio frequency to use to penetrate the vault below grade and use the least amount of power?
I was thinking of using the MoteinoMEGA-USB?
How many digital inputs are available?
What is the standby power usage given some of the custom software that can be loaded to minimize power usage?
The sensor  MoteinoMEGA-USB  units will be place in multiple vaults.  Can I use one common  receiver to read the remote units when I come close to their location?
Is there a sample project that would be similar to my application that I could look at to get an idea of the programming?
Other hardware/software I will need to get started?
Thanks in advance for your help!!

I think given the conditions of this project, you will have to do some experimenting.
If this is in the US, use 915mhz. Start with the simple "free" monopole antennas, then move up from there. Keep them perpendicular to the PCB (the GND plane). In my own experience, the monopole does wonderful from 150ft mailbox to underground basement (below grade, through concrete wall etc).

Minimum power usage is almost an art, the tldr of that is: do whatever you need to very quick, then sleep everything until next time.

QuoteHow many digital inputs are available?

Depends on what peripherals on the chip you use. But the MoteinoMEGA should have plenty for such needs, at least around 30 GPIO.
For power and GPIO/specs see this page (https://lowpowerlab.com/guide/moteino/specifications/).

QuoteIs there a sample project that would be similar to my application that I could look at to get an idea of the programming?

Perhaps, there's many projects in the Projects forum (https://lowpowerlab.com/forum/projects/), take some time to browse there.

Start simple, get 2 units talking and take it from there. You can ask questions here and we can try to guide as best we can.

Thank you!