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• New Sensors and a new indoor unit

  Dave Watkins • 11/20/2015 at 23:56 • 0 comments

  So, after much testing I've switched over to BME280 sensors on both the indoor and outdoor units. The old sensors were working well but a single integrated sensor that's reliable and cheap it a clear win.

  I've also added an OLED screen on the indoor unit for display, while the old 5110 screens were neat, they were ugly and the backlights were terrible. The downside is the OLED screen chews up a ton of RAM on the atmega328 based controller.

  Finally, I've given up trying to run the entire indoor unit via just an atmega328, with the OLED screen there just isn't enough RAM, and so I've added an edison talking over serial to the indoor 328. The Edison handles internet communication via a python script, and stores the wind gusts and rain per minute for 24 hours (something that wouldn't be possible on the atmega alone).

  I could probably run the entire thing off the Edison but since this is my first python programming I'm taking it slow, still it's now reliable and accurate and my original Lipo battery in the outdoor unit is still running without issue. I could almost certainly use a smaller solar panel as charging back to full happens in about an hour of partial sunlight.

  I'm seriously thinking about changing the radios to something with a little more range and am looking at a simple 433Mhz serial radios available just about anywhere. It will mean running software serial on the receiver unit, but I don't think that will be a problem

• Watchdog on Arduino

  Dave Watkins • 08/16/2015 at 02:03 • 0 comments

  I've finally cracked what I believe is the last issue on the sender side. I've got the watchdog enabled in the sender but apparently the Arduino Pro Mini bootloaders don't clear the watchdog timer when they reboot so the atmega sits in a rebooting loop flashing the green LED very quickly.

  I've replaced the stock bootloader with an Optiboot version which appears to be what is shipped with the current IDE's, but you still have to hardwire an ISP of some kind to do the update since the Pro Mini's lack an ISP header.

  The I2C temp/humidity sensor seems significantly more accurate than the old DHT22 which is also noce, even if it does bump up the price I think it's worth it long term

• New Temp/Humidity sensor

  Dave Watkins • 08/02/2015 at 08:32 • 0 comments

  So after fighting with reliability issues with the DHT22's I've switched over to an HIH6130 sensor. It actually made the build simpler as there are less wires and both my temp/humidity and pressure sensors speak I2C.

  We'll see how it goes long term.

  My other concern with the lipo battery and it's projected lifetime seem unfounded. The whole system has been up for the hottest part of summer and very nearly the coldest part of winter and battery performance is still really good. Multiple days of runtime without sun would be fine. In saying that the new sensor may lower that a little as it's powered all the time

• Humidity sensors

  Dave Watkins • 01/29/2015 at 06:25 • 0 comments

  After having the second DHT22 sensor fail (humidity sensor both times) I'm looking at replacing the sensor with an HIH6130 or an SHT15. The HIH is cheaper and speaks I2C rather than something that'll need to be bit banged so I'm leaning that way at this point

• Screen Update

  Dave Watkins • 01/17/2015 at 08:20 • 0 comments

  After spending some time driving the 5110 screens I'm starting to wonder if they are a good idea. Their data density is such that I'm not sure they will convey what I want clearly and they don't look great. I'm considering displaying the Indoor temp on one in large text and the outdoor temp on another and then the remaining data on a different type of display.

  Still thinking about how best to do that
  

• Status 30/12/2014

  Dave Watkins • 12/30/2014 at 02:39 • 0 comments

  External sender is setup and working reporting all data back to a makeshift receiver (currently a netduino as it has network built in)

  I'm pulling in battery voltage and if it is currently charging as well as all the weather stats. I'm reporting to WeatherUnderground and Sparkfun's phant service.

  I plan to move the receiver side over to an Arduino Pro Mini 3.3v using an ESP8266 wireless board to report data and Nokia 5110 displays to show the stats

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