For my first project, I’m looking to build an Arduino-powered weather station for my home. So far, the design consists of two parts: an outdoor module and an indoor module.
Both modules will be able to:
Measure barometric pressure
The outdoor module will be able to:
Send its measurements to the indoor module
Withstand weather and other adverse conditions
Be powered by battery, possibly with a solar assist
The indoor module will be able to:
Display measurements from both modules via an LCD
Preferably with a button to switch between the display of indoor and outdoor measurements
Provide current measurements to users via a web server over wifi
Submit historical measurements to an online service for trending and graphing
Be powered by a wall plug
As far as parts go, I’ve figured on: Indoor station
- Arduino Mega 2560 R3
- Power isn’t that much of a concern since this station will be wall-bound.
- I assume that the WiFi, XBee, LCD, and other libraries will take up a good chunk of memory on their own and my own code will add to that so I’d feel better using an Arduino with some more memory.
- Given all of the things I intend to hook up to the Arduino, I feel that I need a good amount of pins on it.
- Adafruit CC3000 WiFi Shield with ceramic onboard antenna (http://www.adafruit.com/products/1491
- Has a micro-SD slot on it, perhaps to hold configuration info
- Can be configured via iOS or other phone
- Has a prototyping area for weather sensors
- Pins: +5v, GND, D3, D4, D5, D10, D11, D12, D13
- XBee 1mW Trace antenna Series 1 module (https://www.sparkfun.com/products/11215
- with XBee Shield (https://www.sparkfun.com/products/10854
- I intend to use XBees in both modules to connect the them so the outdoor module can send its measurements to the indoor module.
- Pins: D0, D1
- For display, I think I’d be happy with a 16x2 LCD, but I’m unsure as to whether I could or should use a shield for the display. I have a feeling that wiring up a display without the shield gives me more flexibility when it comes to packing all of the stuff into some sort of case. I am somewhat partial to this (http://www.adafruit.com/products/823
- Pins: Dependent on choice of shield vs. no shield. The Mega should have enough pins to handle whatever I choose though.Outdoor station
- Arduino Micro
- This station will be battery powered, so I’d like something smaller and less powerful for this station. I also only don't need to utilize WiFi or a display so I don’t need a ton of pins, only enough for the XBee and weather sensors.
- I can’t use the XBee shield (or at least, I don’t think I can…), so I think I’ll have to wire up the XBee module right to the Micro.
- I’m not sure what I’d need for power. Would a standard set of AA batteries or a 9v work here? Would I be better of with a lithium polymer battery? It gets fairly cold here during winter so I’d like something that’s not going to totally die in the winter time.Weather sensors
- Sparkfun sells a weather shield that has temperature, humidity, and barometric pressure sensors, but I think I’d rather break those out away from the other components on both stations so they’re not affected by any heat that’s given off by them. Is this a valid concern?
- If it is, then I intend to use:
- BMP180 for pressure (http://www.adafruit.com/products/1603
- DHT22 for humidity (http://www.adafruit.com/products/385
- Both of the sensors above have temperature sensors on them, so I suppose I have my choice of the two. Does one perform better than the other?
I don’t have any firm ideas about cases for either station. I like this one (http://www.instructables.com/id/Arduino-weather-station/step10/Buidling-the-Transmitter/
) for the outdoor station, and this one (http://www.instructables.com/id/Plotly-Arduino-Data-Visualization/step4/Building-the-Enclosures/
) for the indoor station, although I would like it to actually surround the components entirely.
Is this feasible given the parts I’ve chosen and the assumptions I've made ? Is there anything I should substitute in place of what I have here?