As I can’t find any home automation commercial product nor DIY project that suits my needs and my requirements, I’m going to design my own assets…

“MUTA” : my home automation project

My home automation system would be wireless, open, cheap, and based on a low power wireless protocol (low electrical consumption and low EM emission).

As of today, I plan to use :

– A server application hosted on a Beagleboard (because of the low consumption, but it could be of course done on any other enough powerfull and “always-on” device as PC), based on some Raphaël JS /AJAX /Cherrypy / SQLAlchemy / Python mix (so platform & OS independent). A basic USB device (with multi-platform drivers) would enable access from the host platform to the dedicated wireless network.

– Wireless devices, dedicated to interfacing and managing sensors or controllers, they should be easily set up and be cheap.

The cost of the different devices (server wireless interfacing or sensors/controllers) should be kept as low as possible. A target cost of 10 to 15 euro would be great.

The UI and the features list should respect the KISS design principle.

I’ll begin by doing a prototype of the core application with 2 basic devices (temperature sensor and heating control) for temperature & heating regulation.

Keep the cost looooow

For this purpose, I won’t use any boost module, they are too expensive. Using two AA rechargeable batteries, I’ll have to deal with a 2V-2.4V supply voltage range, nothing more!

For the same reason, I won’t choose any Zigbee-like protocol for the wireless network. As an example, the cheapest Zigbee module costs $22 at Sparkfun!

I’ll try to use the RFM23 434MHz transceiver from HopeRF instead… The features list is great and it is priced under $5! (and it runs perfectly at 2V). Using a very basic and simple communication protocol, it should be a very good base.

The same approach led me to Microchip microcontrollers for the USB connectivity. The PIC18F14k50, for example, integrates an USB interface for a retail price of ~2 euro. That’s way cheaper that the FTDI or Silicon labs USB modules…

And the latest “XLP” devices from microchip seems to be as battery-friendly as the TI MSP430, so that would be a good alternative too…

(Muta image courtesy of Studio Ghibli, from “the cat returns”/”Neko no Ongaeshi”)

2 comments

  1. y

    I just ran across your site when searching for cherrypy and angstrom. I too am working on a home automation project. I’m making my own RF boards with the hope of using the 6LoWPAN Contiki stack. The beauty of this is you get IPv6 and mesh routing built in. The modules are >$5, but still <$20 (espcially if I ever to go volume on them). Check out my website for details.

  2. Thanks, that’s quite interesting!

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