DIY Zigbee Pressure Sensor

[Digit]

I'm going to make my own sensors in the future if all goes as well as it did today...
Cause today i managed to get a pressure (and temperature) sensor connected to a JeeNode, send the data to my PC by use of Zigbee. And it's all battery powered (except my PC). Here you can read more about it:
http://blog.hekkers.net/2010/01/30/maki ... re-sensor/
http://blog.hekkers.net/2010/01/30/wire ... t-results/
http://blog.hekkers.net/2010/01/31/wire ... small-fix/

[Codeblack]

Excellent job! I'm definitely ordering JeeNodes & XBee modules this week.
I'll also be trying to get a hold of some ATmega128RFA1's, as it's a single chip uC + 2.4 GHz RF radio. Would be great too see if they all play along together nicely .

[Digit]

Thanks! At least i know now i'm not the only one interested in this stuff
Those ATmega128RFA1 look very interesting too, and from what i've seen i think these they are quite new, am i right?
Looking forward to hearing about any progress you make

[RDNZL]

Nice stuff, but I still find that those Zigbee modules are way too expensive.
I would only use them for code-locks, and security sensors not temp or humid.

A simple Jeenode with it's build-in 868Mhz Receiver is good enough for that, currently have tied 3 ds1820 1-wire temp sensors to one, and use it to measure my heating system cv in/out/water temp via rf.

[Codeblack]

The ATmega128RFA1 is very new, released in december last year. I haven't found a shop that sells them yet. Even big distributors like Mouser (here) list them, but have no stock yet. And since I'm not planning on ordering their minimum of 788 pieces, I need to found another source anyway .
It's an interesting new uC. Best features I can see so far:
- Single chip, so radio build-in, means small footprint.
- Lower power consumption (< 18.6 mA for Rx/Tx, < 250nA in sleep), means long battery life.
- IEEE 802.15.4 with support for multiple protocols like ZigBee & 6LoWPAN.
- Cheap solution; even with taxes & at lower numbers (EUR 5.43 at a 788 minimum & excluding taxes I presume).

But I don't want to wait untill it's really available (apparently Atmel has a different interpretation of 'available now' then the rest of us ), so I'm ordering JeeNodes, XBee modules, a XStick and other stuff this week (I'm still making my list from posts in the ZigBee forum, thanks to Digit & others!!). I also want to use JeeNode(s) to communicate with my KAKU's and play with 433.92 MHz communication in general. But I like the ZigBee protocol, especially the security and the ability to create a mesh-network (I might actually need this to reach the shed at the end of the garden ).

I'm also looking for powersupply, dimmer & other usefull schematics with a (very) small footprint. I've started to reverse-engineer some KAKU devices, but if anyone has ideas or even schematics... I'll be very gratefull .

[RDNZL]

I agree about the new ATmega128RFA chip, that looks very nice indeed.

The responses to the announcement on hack-a-day are pretty interesting.
hackaday.com/2010/01/10/ces-update-atme ... ga128rfa1/

[Digit]

Nice stuff, but I still find that those Zigbee modules are way too expensive.

You're right, they are more expensive. But the fact that i like them a lot, makes that irrelevant for me.
Until a certain level of course

[Codeblack]

Same goes for me . I'll gladly pay (some) more for having more fun . And with the ATmega128RFA1 coming available soon (I hope), the balance of price and features you actually need my shift in favor of Zigbee.

[Codeblack]

Good News! Digi-Key has the ATMEGA128RFA1 (and the accompanying evaluation kit ATAVR128RFA1-EK1) available from March 19th.
The ATMEGA128RFA1 will cost $9,46 (EUR 6.92) each and the ATAVR128RFA1-EK1 $77,50 (EUR 56,67). Not sure what transport will cost and what taxes will be added, but I like the sound of that . When ordering 25 the price will be $6,31 (EUR 4,61) each.

The ATAVR128RFA1-EK1 contains 2 evaluation boards with the ATMEGA128RFA1 and requires an STK600 development kit ($206,96). I'm not sure if you need an STK600 for each board. If so, it's quite an expensive evaluation setup .

And, while I'm getting ahead of myself anyway, I'd (also ) want the AVRRZ541 Packet Sniffer Kit to see what's actually going through the air. Would be great to see the mesh network into action, which I guess would be hard (or impossible) with just an XStick and some XBee's.

[Digit]

A small update
So on my desk i have this JeeNode for some time now, equipped with a Pressure sensor. This JeeNode is also controlling a XBee Series 2 module which is configured as Zigbee End Device. All this is battery powered. Recent calculations on power usage of the JeeNode+Sensor+XBee are good enough to expect an acceptible battery life. A Sparkfun XBee RS232 holds another XBee module, configured as Zigbee coordinator. This setup has been operating for more than a week now and looks stable enough to go ahead and connect the Zigbee network (ok, it’s only 2 nodes right now ) to my Domotica system and actually do something with it; something different from logging the incoming pressure data to a text file and reviewing this file periodically to see if everything is still up and running; so i added another (the 16th) interface to my Domotica system and activated it: Zigbee!

In fact all the hard work had already been done in an earlier stage where i created an API-mode interface for Zigbee; in essence, the only thing left to do was making this interface ‘talk’ to the rest of the Home Automation system, add some records in the database for this new sensor type and write a routine that would convert the incoming packets to the measured values of temperature and pressure. And i created a procedure for automatic Node discovery and linking the sensor to the right devices in my Domotica system.

Wow! It’s great to see my first Zigbee/JeeNode based sensor really working! The pressure data is being stored in the database, so in a few hours i can start creating an additional web page to show a pressure chart… well, here it is

[Digit]

Today i finished and literally closed this project, resulting in .. well, just have a look here:
http://blog.hekkers.net/2010/05/05/jeen ... or-closed/

[Mdamen]

Looks really nice and tidy too!
Nice job...