Keyless entry using wireless keyfobs

Forum 2005-2010 (read only) Hardware Interfacing
1

I want to build an arduino into my car to it control my power locks and remotely open my windows. Once I understand what I need it shouldn't be too hard to hook up a couple of relays.

I saw this on sparkfun: http://www.sparkfun.com/commerce/product_info.php?products_id=8602

But for $50 plus another arduino and some relays I could just buy a commercial system. Does anyone know of some cheaper solutions?

I have a set of wireless flash triggers for my photography stuff, similar to this: http://cgi.ebay.com/PT-04-wireless-flash-trigger-4-channels-v2s_W0QQitemZ350180640305QQcmdZViewItemQQptZDigital_Camera_Flashes?hash=item350180640305&_trksid=p3286.c0.m14&_trkparms=66%3A2|65%3A15|39%3A1|240%3A1318

I was thinking I could use that; it basically acts like a n/o switch with a remote trigger. It would only give me one button but I could have sequences. For example:
1 press could lock
2 presses could unlock
3 presses could unlock and open the windows

It would have a brief timeout, probably 2 seconds to prevent unintentional unlockings.

I'd really like a traditional keyfob with multiple buttons though. Any ideas?

2

There are many vendors on ebay that sell just the keyfob transmitter and a bare receiver with 1, 2, or 4 buttons for $10-15 shipped (though most of them are in China, so the real price is more like "$12 + 2 weeks of impatient waiting" :slight_smile: ).

The Nordic radios are fancier than what you need for your application: among other things, they're all transceivers, so you'd be paying for a two-way link when all you need is a 1-way link. Otoh, if you wanted to be able to do something like, say, have the Arduino monitor the interior temperature and warn you so you could remotely open the windows and keep your CDs from melting, the Nordic units might be just the ticket.

Ran