-----Original Message-----
From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of=
 John Gardner
Sent: 07 September 2012 02:07
To: Microcontroller discussion list - Public.
Subject: Re: [OT]:: Tyre pressure readable remotely using RFID devices embe=
dded in tyres.

>Has'nt the scheme been around for a while?
>
>ISTR my sister's 2011 Subaru has low-tire-pressure alarms...

Yes low pressure warning systems have been around for a few years now - the=
y have to be fitted to any car that use run flat tyres.

However not all tyre pressure warnings use RFID.  You can do it "cheaply" b=
y monitoring the relative speeds of the wheels via the ABS sensors - a flat=
 tyre has a smaller effective circumference. According to wikipedia you can=
 now determine whether a tyre is flat by looking at the spectral content of=
 the wheel speed signal.  Presumably a flat tyre will cause some kind of ji=
tter that can be measured.

Mike



=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
This e-mail is intended for the person it is addressed to only. The
information contained in it may be confidential and/or protected by
law. If you are not the intended recipient of this message, you must
not make any use of this information, or copy or show it to any
person. Please contact us immediately to tell us that you have
received this e-mail, and return the original to us. Any use,
forwarding, printing or copying of this message is strictly prohibited.
No part of this message can be considered a request for goods or
services.
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D

--=20
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.