Comments on: Google Code Blog: Google PowerMeter API introduced for device manufacturers http://www.adafruit.com/blog/2010/03/04/google-code-blog-google-powermeter-api-introduced-for-device-manufacturers/ electronics, open source hardware, hacking and more... Thu, 09 Sep 2010 15:52:57 +0000 http://wordpress.org/?v=2.9.1 hourly 1 By: MoJo http://www.adafruit.com/blog/2010/03/04/google-code-blog-google-powermeter-api-introduced-for-device-manufacturers/comment-page-1/#comment-9420 MoJo Thu, 04 Mar 2010 15:58:10 +0000 http://www.adafruit.com/blog/2010/03/04/google-code-blog-google-powermeter-api-introduced-for-device-manufacturers/#comment-9420 I have been inspired to try something similar. My main goal is cost reduction. The Zigbee modules are handy but not exactly cheap. An alternative would be Bluetooth RS323 modules which can be bought for about 1/3rd the price. There are two options - radio or wired. Radio is a good way to go I think. Using cheap transceivers and having the microcontrollers taking the readings buffer the data instead of sending it continuously it should be possible to have lots of them operating together on one frequency. Another advantage is that the uprocs will log data even if the receiving computer is not on. Wired is not very practical unless you use power line networking. There is no easy and safe way to do it as far as I can tell, at least not cheaply. On the other end there will be a USB/RS232 receiver. Routers that can run DD-WRT are ideal for logging and uploading the data, especially as they can run on just a few watts and have built in LAN/Wifi. The first versions will be built into power meters like the Tweet-a-Watt, but I am hoping to have hall-effect sensor based ones too for building into devices and power strips. Ubiquity is the goal. I am hoping to power everything from the mains too. It's not hard really, and I have had good results re-purposing those little USB chargers you can get for a pound or two. I have been inspired to try something similar. My main goal is cost reduction. The Zigbee modules are handy but not exactly cheap. An alternative would be Bluetooth RS323 modules which can be bought for about 1/3rd the price.

There are two options – radio or wired. Radio is a good way to go I think. Using cheap transceivers and having the microcontrollers taking the readings buffer the data instead of sending it continuously it should be possible to have lots of them operating together on one frequency. Another advantage is that the uprocs will log data even if the receiving computer is not on.

Wired is not very practical unless you use power line networking. There is no easy and safe way to do it as far as I can tell, at least not cheaply.

On the other end there will be a USB/RS232 receiver. Routers that can run DD-WRT are ideal for logging and uploading the data, especially as they can run on just a few watts and have built in LAN/Wifi.

The first versions will be built into power meters like the Tweet-a-Watt, but I am hoping to have hall-effect sensor based ones too for building into devices and power strips. Ubiquity is the goal. I am hoping to power everything from the mains too. It’s not hard really, and I have had good results re-purposing those little USB chargers you can get for a pound or two.

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