WTF is going on here?
At the heart of the weather station is an Arduino running at a meager 16MHz on 5 volts. Approximately every 5 minutes, it retrieves the current temperature and humdity readings from the attached SHT15 sensor. The readings are decoded by the Arduino into a simple string and sent to the RN-131C (WiFly Shield). The RN-131C is configured to then take the string and automatically post it to ThingSpeak using the WiFi network.
Charts and Goodies
Parts List
- Arduino Uno - $29.95
- Arduino ProtoShield Kit - $16.95
- WiFly Shield (RN-131C) - $89.95
- Humidity and Temperature Sensor (SHT15) - $41.95
Pending Add-ons
- Ambient Light Sensor (TEMT6000) - $4.95
OR Light Intensity to Frequency IC (TSL230R) - $5.95
OR Light Intensity to Frequency IC (TSL235R) - $2.95 - Barometric Pressure and Temperature Sensor (SCP1000) - $34.95 -
Abandoned Ideas
- Sending data to Pachube has been temporarily abandoned in favor of the easier API offered by ThingSpeak which can easily be handled by the RN-131C.
- I was going to use a DeadOn RTC (DS3234) to get accurate timestamps that could then be logged to an SD card. I later decided it wasn't necessary since I'd be sending the data out to ThingSpeak for storage. I'm not too concerned in loosing information if my internet connection is offline.
- I tried the XBee Shield after my failed attempt with the Ethernet Shield. It would relay information to my MacBook Pro which would then post the data to Pachube using a small Processing sketch. Unfortunately, it made my station dependent on my MacBook Pro which I occassional take places. I ended up replacing it with a WiFly Shield. It's still very useful, just not on this project. I recommend using the XBee Shield from SparkFun, it has a switch to determine if the UART connects to the USB or Xbee. The "official" Arduino XBee Shield has 2 jumpers that are annoying to reset after a few times
- I was originally planning on using the Ethernet Shield with integrated microSD card slot to communicate with Pachube. However, it turned out it has one major flaw: it didn't relinquish control of the SPI bus. There are board modifications that can be performed but I didn't bother, there are also alternative Ethernet Shields available without the flaw. Having to teathered to my router to test also became annoying. I'll probably mod the board in the future for a different project.