Hey guys. I tripped over this thread by accident but it comes at a good time. I have been working on some code that uses a Moteino to pick up the wireless transmissions from my Davis weather station.
Check it out here. It is possible that you might have one of these outdoor units in your neighborhood and could leach off of it for free
Otherwise, the outdoor unit can be bought separately, and that gets you a high quality, solar powered instrument for giving you wind speed, wind direction, rain, outdoor humidity and optionally UV, solar, leaf wetness, and ground moisture readings.
I am now in the middle of writing up a blog post that details how I have emulated the serial interface used by the Davis console so that the Sandaysoft Cumulus weather station software can read from it and collect not only the outdoor data, but data from a BMP085 and a DHT22 to get indoor data as well. This will go online today or tomorrow and I'll post a link when it is up.
It would be great if we could work together here to come up with something that would work for your needs for a transmitter and mine for a receiver. Let me suggest the following.
- provision for a DS3231 clock module with something
like this. This would allow a receiver to track things like daily highs and lows, accurately timestamp observations, etc when not connected to a PC. The Memory Module is bound to come in handy. And this module takes a battery backup to keep time when powered off.
- why not just design for a header for a BMP180 module (three bucks on EBay) so you don't need to do the tricky soldering that package requires?
- just use the temperature data from the humidity sensor DHT22
if you are running tight on space or pins. It isn't expensive and you often want to know one when you know the other. It is accurate enough, and you get temperature when you read humidity anyway.
- consider standing the DHT22 upright on the board to make room for other stuff if necessary
I like the idea of designing for these inexpensive modules rather than discrete parts when you can. That way stuff can easily be populated at a later date if you like and it keeps the overall build simple.
As an aside, it is very dry here and I've found that as I move my breadboarded prototype around, I often get a false burst of receive packets. I
think what might be going on is spurious RFM69 interrupts being generated thanks to static electricity. I am going to try a pulldown on the interrupt line to ground to see if this cleans things up. Anybody else ever see this?