battery-powered RF transmitter technology suggestions 2

[geekEE]

I need to design a battery-powered device that transmits a small amount of data (two to four bytes) about once a minute over an RF link. Conceptually, consider it similar to those remote thermometers that Oregon Scientific makes. I think those transmit on 433MHz.

The question that I have is, what kind of RF technologies and chips should I be looking at to give a decent battery life and pretty low cost? 433MHz ISM? Zigbee? Something else?

 

[itsmoked]

G0 here:

http://www.linxtechnologies.com/

I have used their stuff several times. They are very friendly and helpful. I have used their stuff several times with good effect. Heck I even got into Popular Science Magazine with a product based on one.

Very inexpensive with good development kits.

You can get all of their stuff at Digikey.com

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[richs]

Hiya-

Another alternative is the Radiotronix modules. They
are available via Mouser electronics and are also dirt cheap.

They are a little bit of a pain to use however, you have to
really do some discrimination to get the superregen receiver
to isolate the noise from the signal. But, the transmitters
are extremely small, run from a couple of batteries and the
receivers run from 5 Volts. The transmitters can be on/off
keying.

Look at the RCT line of products. Mouser has them for
$4 and $5 US. You can see them on the catalog page:

http://www.mouser.com/catalog/626/135.pdf

http://www.radiotronix.com/

But they work as advertised. YMMV. I am not affiliated with
either radiotronix or mouser. Just a customer.

Cheers,

Rich S.

 

[itsmoked]

Good to know of an alternative Rich.

geekEE; do look at these company's app notes as there are some serious details that must be adhered to for success.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[VEBill]

"...over an RF link."

How far? There's lots of answers for 30m. Fewer for global coverage.

Look at the chip sets and application notes for Garage Door Openers and Auto Remote Controls (OEM keyless entry or after-market remote starting). Even if they only send two or three discrete button presses, you could loop those into a code.

 

[nbucska]

I wonder if it wouldn't use less battery power to use
a micropower microcontroller and transmit only if there
is any change ?

Plesae read FAQ240-1032
WEB: <

http://geocities.com/nbucska/>

 

[VEBill]

If you minimise the number of transmissions, then the system might need a two-way link to provide 'acks' back.

There are other solutions: Maybe 'upon change' but at least once every few minutes anyway. And with a time-out indicator on the receiver.

 

[nbucska]

About radiotronix: Use modulation or error correction !

Plesae read FAQ240-1032
WEB: <

http://geocities.com/nbucska/>

 

[MikeHalloran]

FCC rules for 433MHz _severely_ limit the duration and rep rate of regular transmissions. Battery life should not be a huge problem.



Mike Halloran
Pembroke Pines, FL, USA