Multiple Shields?

[KyleYankan]

Hi,
I'm trying to find out about the feasibility of a project, an dusing an arduino to do it. I've never used an arduino, but due to power constraints, it seems like a logical choice. Please allow me to describe the constraints and goals:

My brother and I share a cabin in upstate PA, which has no supplied power, no water lines, no communication lines. We provide all the amenities to our guests (friends and family) through solar power, batteries, generators, a 250 gallon tank of water, and a septic tank. This works well for us, for the most part. However, being that we're in Upstate PA, with no running water, we keep a supply on-hand, via a 250 gallon tank. This tank, being the lovely convenience that it is, likes to freeze up on us all winter long. So far, we've been draining it, and having no toilet/showers/running water for 4 months of the year, but we're hoping to change that with our recent investment in some solar panels.

The problem here is that we need to use our power very diligently, since we're only generating around 15ampHours a day, or enough to turn on a 100watt heater for 90 minutes. So we want to reserve what power we can when the water is not frozen, and have some reserve power to keep the water from freezing on the cold nights.

What I'd like to do is install a system that monitors the temperature in a few places (The external of the tank, internal of the tank, outside ambient temperature), the battery voltages (12v batteries, 450ampHours), use a GMRS/GMS connection to send a text message/e-mail once a day, as well as when the temperature gets dangerously low, and accept a text message command to turn the heater on via a relay.

From my research into Arduinos, this would mean I need a GMRS shield, a data logger shield, and a relay shield all connected to one Arduino. Is such a thing possible? Can you piggyback all of these devices? Or should I look into an alternative way of doing this (such as a Raspberry Pi)?

Furthermore, does anyone know how the signal is on the GMRS shields? At the location, on my cell-phone, I barely get a signal. So, if the shield is as sensitive, the raised antenna should substantially help.

[adafruit_support_bill]

I don't have any experience with the GMRS shield, but others may chime in here.

What functions of the Data Logger shield do you plan to use? Are you just reading temperatures to report via text message, or do you want to log them to file as well. If you don't need the file logging, you can reduce the number of required pins (and chances for pin conflicts)

The heater control can be done without a shield. The PowerSwitchTail will switch up to 15A and just needs a single digital out pin.

[KyleYankan]

I thought the data logger would be required to hold the temperatures for the day before e-mailing them, as well as to interface to the temperature probes.

[adafruit_support_bill]

Temp probes can be interfaced via a simple protoshield, but it sounds like you do have a use for the logging too. The main question then is whether there are any pin conflicts between the logger shield and the GMRS. The data logger uses digital pins 10-13 for the SD card interface and analog pins 4 & 5 for the RTC.

Other pin requirements will depend on your choice of temperature sensors. Simple analog sensors like the TMP36 will require one analog pin each. Digital sensors such as the DS18B20 require just one digital pin to communicate with any number of sensors.

[floresta]

Can you piggyback all of these devices?

Here's a resource that may be of help: http://shieldlist.org/

It currently has "Pin usage details for 285 shields from 114 makers, and counting!"

Don