Re: Wheelchair proximity detection

[nobody@xxxxxxxxxxxx (Dave Houston)]

I did a bit of googling and, as I expected, quickly found several available
systems that address this need. Most require a switch on the chair but they
have things like chin operated switches. Since you didn't respond to my
ealier question about how you control the chair, I don't know whether a chin
switch is appropriate but I think you'll probably have better results by
communicating with companies who make automatic door openers for wheelchair
access than you'll get here. Here's one link.

     http://www.opensesamedoor.com/

"David Norwood" <judapeno@xxxxxxx> wrote:

>I need to trigger an automatic door opener when my wheelchair is within
>about 3 feet.  I would like some sort of radio transmitter on the wheelchair
>and a receiver near the door.  Here are my requirements:
>
>- it must work at about 3 feet.  I can't find an affordable RFID reader that
>works at this range.
>
>- the transmitter must operate on a battery for at least two months
>continuously.  I like Bluetooth, but can't find a low power transmitter.
>What do they use on those automatic pet doors?
>
>- it must provide a simple contact closure, or have a serial or usb
>interface and Linux drivers.  Zigbee?
>
>- I'm not too concerned about security.  There are easier ways to get into
>my house than spoofing a radio signal.
>
>- it must not require too much soldering.  I have friends that can help with
>this, but within reason.
>
>I've seen various radio transmitter modules on the web, but don't know how
>much power they require, and how to interface a receiver to my computer.
>I've figured out how to do this with Bluetooth, but I have the power issue.
>
>David
>