I'm using miceuz's Chirp I2C sensors here. Found it to be much more reliable and consistent than the cheap analogue sensors, particularly dealing with large outdoor temperature variations. The "rugged" model works a charm.

I'm getting about 12 months off 2x AAA batteries, using some aggressive sleeping. As you've surmised, hook up the power in line to a Digital Out so you're not constantly powering the sensor when your board is asleep. You'll need to wait() about 200ms for the board to wake up after supplying power, and take a few dummy readings each time you wake it for it to stabilise.

@robosensor I wrote a bridge to use on the Linino side of the Arduino Yun for this:
https://github.com/peterdey/Yun-Linino-NewBridge

But there's no reason you couldn't use this on an rPi - you'll probably just need to turn the baud rate down to 115200.

@Mark-Swift: You'll need to replace Serial.Print with node.logMessage - but yes, I use it for transmitting debug messages, wirelessly, to the controller.

No gateway modifications required (the gateway will just pass the message over to the controller). Old versions of MYSController (e.g. 0.1.2.276) would actually show the debug messages as a LOG_MESSAGE in the "Messages" tab; later versions hide it away in the "Debug" tab.

@Mark-Swift : If you're happy to modify the MySensors library in an unsupported way, I've added a logMessage function to transmit text/debug messages from remote nodes:
https://github.com/peterdey/MySensors-Arduino/commit/f5f339b71620ec3cd896304a2ca6aba40ad40218

Found it useful, particularly in conjunction with MYSController OTA firmware updates.

@hek - would it be possible to get a subforum for MYSController stood up in the Controllers forum? This thread is getting pretty long and off topic (also, the RSS feed stops at the 27th post)

Azure IoT Hub supports the MQTT protocol directly, or you can use a "Protocol Gateway", which translate MQTT to Azure's REST API.

See here for interfacing directly with MQTT: https://azure.microsoft.com/en-us/documentation/articles/iot-hub-mqtt-support/

For using a Protocol Gateway, Microsoft provides a reference protocol gateway (https://github.com/Azure/azure-iot-protocol-gateway), and some pretty good documentation about using an MQTT protocol gateway to interface with Azure IoT Hub.

Either way, you should be able to use the MQTTGateway sketch on your gateway to push data up to Azure.

@akbooer: Just using it as a Serial/Ethernet gateway.

Though there's plenty of documentation available on getting node.js working on the Yun; which you could use to run up the sample node.js controller from MySensors.

@akbooer: I'm currently running the SerialGateway sketch on my Yun.

Simply replace the Serial calls with Console, and add in the relevant includes at the top.

Performance isn't stellar, but it's "good enough" for most use-cases. OTA firmware updates are quite slow - you could speed these up significantly by replacing the Yun Bridge with a PySerial bridge at 250kbps.

@Chester: They're usually about $30-35 per unit. On the expensive side, but I'd prefer to have something buried in my wall that I know I won't have to pull out in 12 months time - and also that is unlikely to start a fire...

They're quite small. Designed to fit into the Clipsal faceplates for Cat5/Cat6 jacks.

I use these in Australia:
https://www.clipsal.com/Trade/Products/Electrical-Accessories/Electronic-Accessories/USB-Charger

AS/NZ safety certified, etc.

Happy to test here. ATmega328 @ 1Mhz.

Channel: 76 / 250kbps
CSN: 7
CE: 8

On-board LED on D9 (not 13)

For some reason, @Ruud-Harmsen's bootloader didn't work for me.

My copy's attached. Same pins and rf24 config; but also added five flashes to an LED connected to pin D9, so you can tell when it's in a reboot loop.

Source here: https://github.com/peterdey/MySensors-Arduino/tree/master/MYSBootloader

MYSBootloader.hex