[jpwright]

Looks great! Out of curiosity, why go with the hub/node approach using ZigBee for sending such a small amount of data? There are WiFi modules like TI's CC3000 (http://www.ti.com/product/cc3000) available for very low cost that would make separate hub hardware unnecessary. This is the product used in Spark Core (https://www.spark.io/), for example. I imagine there are a few different reasons why you might spring for a hub-based solution despite the higher cost, but just wondering what your thinking is.

[swamp40]

We use a wifi module in a battery operated environment (we kill power to the module when it isn't in use).

It uses about 225mA @ 3.2V.

The connection/handshaking take about 5-7 seconds to talk to a local server, plus the time for whatever data you are sending.

When talking to an internet based server, the connection time can extend out to 20+ seconds.

So you can see wifi isn't the greatest choice for low power/battery operated environments.

(Now on something you don't mind recharging a few times a week, it is perfect.)

[clement87]

Exactly, for Notifon the transmit time is 40ms. That's why it can run on a small and sexy coin battery (CR2032).

[mkesper]

I much prefer standard mignon types. They are an ubiquity.

[clement87]

I know, it's all about the battery life (about years). The ZigBee chip require only 40mA in transmit and less than 1uA on idle mode... You can't do the same with a WiFi chip, ask Spark... Also, with Hub/Node there is no "association" need like entering the WPA key. It's all automatic