need mangetic sensor

Archiver · 2000-03-13 15:32

I want to mount a magnet on a wheel and have the stamp sense the magnet
passing by
I want to signal conditioning to be built in so that the stamp just needs to
look for hi or lo

whats is this called, who sells it, for how mauch

thanks

\
richard

Archiver · 2000-03-13 16:23

A hall effect device will do the trick. You have to provide a bias voltage
and may need some signal conditioning depending on the exact device you
select. If the wheel turns slowly, you might be able to get away with a reed
switch. This is like a relay operated by an external magnet. These are
commonly used in alarm systems to detect when a door/window is open. Of
course, they need some time to recover and like all physical switches may
have bounce. So you'd want to debounce it in software and you couldn't
measure anything too fast that way.

Good luck,

Al Williams
AWC
*Floating point math for the Stamp, PIC, SX, or any microcontroller at
http://www.al-williams.com/awce

>

Original Message

> From: dakota [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=09anlI69LzUzh22RCUiKz_4xeHUPGigSdqemvzSmVogqjBwg5ZUHPy0XnAYbMUDL]umc@i...[/url
> Sent: Monday, March 13, 2000 9:33 AM
> To: basicstamps@egroups.com
> Subject: [noparse][[/noparse]basicstamps] need mangetic sensor
>
>
> I want to mount a magnet on a wheel and have the stamp sense the magnet
> passing by
> I want to signal conditioning to be built in so that the stamp
> just needs to
> look for hi or lo
>
>
> whats is this called, who sells it, for how mauch
>
>
> thanks
>
> \
> richard
>
>
>
>
>

> -- 20 megs of disk space in your group's Document Vault
> -- http://www.egroups.com/docvault/basicstamps/?m=1
>

Archiver · 2000-03-13 17:07

I'm doing this also, and recommend the following, all from DigiKey: Part #
9208B, 18-page book summarizing different Hall ICs and their
characteristics, part # HE510-ND, pack of 10 small magnets, and part #
DN6851A-ND, bi-pullup SIP Hall effect sensor.
Dennis

Original Message

From: dakota [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=frqxe9RrTzox95UnwCZFscieDCawh9QYVBfLsVEoB3Hi8p-gTvz6GMMlLOXuZwa2hwg]umc@i...[/url
Sent: Monday, March 13, 2000 7:33 AM
To: basicstamps@egroups.com
Subject: [noparse][[/noparse]basicstamps] need mangetic sensor

I want to mount a magnet on a wheel and have the stamp sense the magnet
passing by
I want to signal conditioning to be built in so that the stamp just needs to
look for hi or lo

whats is this called, who sells it, for how mauch

thanks

\
richard

-- 20 megs of disk space in your group's Document Vault
-- http://www.egroups.com/docvault/basicstamps/?m=1

Archiver · 2000-03-13 17:21

Why not just mount a reed switch near where the magnet passes and let
the Stamp look for a simple switch closure? That would be a high,
wouldn't it?

Bob Oldham

dakota wrote:
>
> I want to mount a magnet on a wheel and have the stamp sense the magnet
> passing by
> I want to signal conditioning to be built in so that the stamp just needs to
> look for hi or lo
>
> whats is this called, who sells it, for how mauch
>
> thanks
>
> \
> richard
>
>

> -- 20 megs of disk space in your group's Document Vault
> -- http://www.egroups.com/docvault/basicstamps/?m=1

Archiver · 2000-03-13 17:53

Look at Hall Effect Sensors they are small and work well with stamps

dakota wrote:
>
> I want to mount a magnet on a wheel and have the stamp sense the magnet
> passing by
> I want to signal conditioning to be built in so that the stamp just needs to
> look for hi or lo
>
> whats is this called, who sells it, for how mauch
>
> thanks
>
> \
> richard
>
>

> -- 20 megs of disk space in your group's Document Vault
> -- http://www.egroups.com/docvault/basicstamps/?m=1

need mangetic sensor

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