SparkFun Forums

[thumperj]

Hi, I've got an odd request but I'll try to be brief. My wife has been diagnosed with terminal cancer. However, she's within 6 hours of finishing her law degree. Her teachers have agreed to allow me to come to class with her in case something happens but I have to sit in the back of the room.

Here's my need. I need to build a simple circuit that will act as a really simple comm device between she and I that will be a signal that she needs my help. We've found that during chemo, nausea comes on quick so I want her to be able to press a button on a tx that causes my rx to light up/vibrate - whatever. The output type on the rx is easy. What I don't know how to start is getting her input signal (a button press) to my rx.

Can someone suggest a starting point (circuit diagram, modem board, anything)? I'm not a complete noob just a noob to RF and I just need to get this done as simple as possible and quickly. Class starts Monday.

Thanks for any help!
Chris

[redteardrop]

That sounds like a good idea, I haven't used the RF, I'm trying to use bluetooth. I am pretty new, but from what I've seen you should be able to use a wireless connection to 2 units. her unit might just be able to use a button to close the circuit on the TX line to transmit a signal to you. On your unit, have a mcu that detects the input and then closes a relay that's connected to a small vibrating motor with some LEDs or something. Bluetooth would be expensive to make, so the RF might work just as good.
In all honesty though, if all you need is a signal, you might just be able to use a walkie talkie set that has the page function. She just pushes a button on the unit and a small beep shows on yours.

[riden]

If you want to roll your own solution, you could use a UHF Receiver/ Transmitter pair equipped with encoders and decoders. See this thread for a discussion. Don't panic at the thread length, there was an issue with the encoder/decoder which was resolved at the end of thread. It is pretty easy to put together something like this, however the packaging will be may or may not be a challenge.

The following products have nice transmitters like you see on remote car lock systems. If you want a kit or assembled product, Rentron or KitsRUs (CPS157 or CPS180) have rolling code tranmitters and receivers that should work for your purposes.

I hope you get things worked out the way you would like, and my thoughts will be with you and your wife as she completes her degree.

[sdvic]

You can go to any hobby shop, and buy a cheap radio controlled transmitter...and an r/c receiver with one actuator. no design...no soldering.

Vic

[thumperj]

Fantastic! The LICAL-LS dec/enc pair is exactly what I needed. I've already ordered a few sets to start building immediately. Thanks a bazillion!

Thank you for all your suggestions and well-wishes.

For what it's worth, here's a site I put up that talks about my wife's cancer. I keep it updated daily with status of her condition.

Cheers,
Chris

[riden]

I don't think Rentron is selling the original LICAL chips, but it wouldn't hurt to mention you want the ones that Rentron produced and not the ones from Lynx. You could reference the SparkFun thread. I know Bruce will remember.

And you're welcome. The new chips work exactly as advertised.