Extremely Simple RF Data Link, similar to basic on-off remote control

uxorious

I am looking for some input on a design I am working on. Phase 1 of the design requires no microcontroller, so I would like to prototype without one. Phase 2 will add a microcontroller, but will also increase PCB real estate and power so I have plenty of options there. Anyhow, here is where I am at with my train of thought:

I need a 3 channel RF link that is only required to work at a distance of 8 feet. The transmitter must fit within a box that is Polycase P-1304TX (2 x 1.28 x 0.45) and run from a 3 volt button cell. The antenna can hang free from the box. The receiver must fit within a cavity that is 2"x 2"x 4" with room for a 9 volt battery. The transmitter will send the state of three switches and the receiver will display these states on a bank of LEDs.

My first thoughts are of the cheap keyfob tx/rx kits you find on eBay or using Linx modules with an encoder chip, but I would like to see if I am missing a better idea. Going with the Linx modules may make it easier to migrate to phase 2, but will also make phase 1 a klittle more expensive. I am trying to keep the total cost around $50 and my bill of materials without the RF link circuitry is at $19 already.

thanks in advance for any input.

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~~ dRu ~~

Phil Pilgrim (PhiPi)

You might take a look at Micrel's QwikRadio chips. In conjunction with a Holtek encoder/decoder (search DigiKey), they might do what you want.

-Phil

Bean

I would use IR if you can. 8 feet should be no problem as long as you have line-of-sight.

Bean.

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Did you know that 111,111,111 multiplied by 111,111,111 equals 12345678987654321 ?

www.iElectronicDesigns.com

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Steve in NM

I've recently started using these at $9 for the set·(and the price has since dropped by $5 ) : http://www.sparkfun.com/commerce/product_info.php?products_id=7813·but they won't meet your power requirements.

There's these: http://www.rentron.com/remote_control/TXLC-XXX-LR.htm·but there·goes your budget at· close to $50 for the TX/RX.

When I began my search. I first considered the keyfob route, but it's·really the·RX that you pay for. I went with the Sparkfun offering for the cost benefit, and will eventually upgrade to what Reynolds is now carrying. The beauty is the ability to swap out the hardware and use the existing code. In fact, I started with code that I pilfered from Parallax, and everything worked out of the box.

Since your path ultimately leads to a processor-based TX, I'd suggest you bypass your first phase. You'll save money in the end.

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I'm not a complete idiot! Some of my parts are missing.

Steve in NM

Oh, and I agree with Bean. If cost and space are that critical, IR is the way to go.

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I'm not a complete idiot! Some of my parts are missing.