Alt-BEAM Archive

Message #08867



To: "'beam@sgiblab.sgi.com'" beam@sgiblab.sgi.com
From: Wilf Rigter Wilf.Rigter@powertech.bc.ca
Date: Thu, 6 Jan 2000 17:54:28 -0800
Subject: [alt-beam] Re: OT:Car Remotes...Clarification


Nice work Ben!

Judging from the use of that ultra low power opamp WhistleBlower TX Timer
circuit, you may want to change your comment about BEAM applications for
opamps in your excellent BEAM ELECTRONICS page

http://www.wollongong.apana.org.au/~ben/info/index.html

regards

wilf

> -----Original Message-----
> From: Ben Hitchcock [SMTP:beh01@uow.edu.au]
> Sent: Saturday, December 18, 1999 8:01 PM
> To: beam@sgiblab.sgi.com; beamboter@hotmail.com
> Subject: Re: OT:Car Remotes...Clarification
>
> >From: "Jim Cook"
> >I messed up, I wasen't clear, I think.
> >
> >I am refering to the little key chain Car ALARM remotes, which lock and
> >unlock the doors, and set the alarm.
>
> Ahhhh.
>
> Well in that case, it's usually around 300 MHz. The higher frequency is
> so
> you can use a smaller transmitting aerial.
>
> >Any one know about those?
> >
> >As for the Crystal it has 315M6, and 591. Any guess which is the freq.?
>
> I would guess that your doodad transmits at 315 MHz. If the silver thing
> is
> sort of flat and disc shaped like a little button, check underneath the
> board to see how many legs it has. If it has three then it is almost
> certainly a SAW (Surface Acoustic Wave) resonator. I have no idea how
> these
> are different to a normal crystal resonator but apparently they are.
>
> I just completed a project for university using one of these devices. If
> anyone's interested, you can find schematics and pictures at:
>
> http://www.wollongong.apana.org.au/~ben/elec250/
>
> There's a pretty poor excuse for an index there but that's all I did in
> the
> time I had available.
>
> There's the product webpage as well, but it's not that interesting -
> mostly
> just pages trying to entice you to buy the product (It's not really for
> sale
> but we have to pretend for the uni's sake).
>
> It's at
> http://www.wollongong.apana.org.au/~ben/elec250web/
>
> Ben Hitchcock



8868 Fri, 07 Jan 2000 13:02:19 +1100 [alt-beam] Re: Pressure Sensors beam@sgiblab.sgi.com Elmo OK its a very low tech approach but you can make a nice tactile pressure
sensor using a couple of bits of PCB copper sheet and some anti static
foam.

The foams resistance changes as you compress it and thus you can get an
indication of which pad on the under side of you foot has touched the
ground first, and to a lesser degree how much pressure is being applied
to a pad (its going to be in the range of none, low pressure, high
pressure).

I can post more info if your interested. I have an article from a very
old robotics journal on how to do it.

Elmo

Ian wrote:
>
> Hi, I was just looking around for pressure sensors to use on my biped
> walker. The first place I looked was Jameco and I found one that looked
> good. I thought to myself "I'll get on the net and order 8 of them". That's
> when I looked at the price and noticed that they were $10 each. No way I
> could spend that much money. I then checked DigiKey. Prices there range from
> $13 to $150. Ouch! I then checked that web site that Evaristo posted but I
> couldn't find any prices on their site. Anyone know of a cheap source for
> pressure sensors? Thanks
>
> Laterz
>
> --------
> There is only one true "SyNeT"
> BEAM Online - http://www.beam-online.com
>
> The software said Windows95 or better, so I got a Mac!

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