share I/O pins with IR detector

Archiver · 2000-03-17 05:36

Hello again all. I was asking about sharing Pins with Ir detectors that
outut a 0(low) for detection. My bumper sensors use a pullup resistor and
also output a 0(low) on detection. If I use the Diodes as somebody
suggested,wont the two sensors step on each other?
how would my bumper send out a low state and the IR sending out a high state
and both feeding into the pin at the same time?
I would try it,but hate to burn up my stamp. I dont care about losing a
cheap IR detector,but hate to lose a stamp <S>
Below is what I would like to do, without the smell of smoke <S>

+ 5V
/
\ resistor
/

| | IR | Radio shlock
detector outputs a 0 for detection
Pin

|

Archiver · 2000-03-17 18:31

>also output a 0(low) on detection. If I use the Diodes as somebody
>suggested,wont the two sensors step on each other?
>how would my bumper send out a low state and the IR sending out a high state
>and both feeding into the pin at the same time?
>I would try it,but hate to burn up my stamp. I dont care about losing a
>cheap IR detector,but hate to lose a stamp <S>

The diode circuit that another list member described
for you keeps the inputs from "stepping on each other."
It's called a "wired-OR" circuit. Either source can
pull your input LOW. If they're both HIGH, nothing happens.

Reg Neale

Archiver · 2000-03-17 19:23

Kerry:
If you connect two diodes as I suggested, the sensors are isolated from each
other. You connect a diode from stamp pin to the first sensor, and another
diode from the stamp pin to the 2nd sensor. The diodes point away from the
stamp toward the sensors. Therefore, the sensors can sink current, but not
source current. Then you use a pullup resistor on the stamp pin since the
sensors can no longer pull up the stamp. A 10K resistor would be OK for
pullup.

Ray McArthur

Original Message

From: Barlow <admin@m...>
To: <basicstamps@egroups.com>
Sent: Friday, March 17, 2000 12:36 AM
Subject: [noparse][[/noparse]basicstamps] share I/O pins with IR detector

> Hello again all. I was asking about sharing Pins with Ir detectors that
> outut a 0(low) for detection. My bumper sensors use a pullup resistor and
> also output a 0(low) on detection. If I use the Diodes as somebody
> suggested,wont the two sensors step on each other?
> how would my bumper send out a low state and the IR sending out a high
state
> and both feeding into the pin at the same time?
> I would try it,but hate to burn up my stamp. I dont care about losing a
> cheap IR detector,but hate to lose a stamp <S>
> Below is what I would like to do, without the smell of smoke <S>
>
> + 5V
> /
> \ resistor
> /

> | | IR | Radio shlock
> detector outputs a 0 for detection
> Pin

|

|
> | |______|
> |
> |
> /
> / switch
>
> |
> ---
> - Gnd
> Sincerely
> Kerry
> http://Mntnweb.Com
> WWW hosting and Authoring
> Admin@M...
>
>
>
>

> eGroups.com Home: http://www.egroups.com/group/basicstamps/
> http://www.egroups.com - Simplifying group communications
>
>

Archiver · 2000-03-17 20:39

This is not my question. My question was locating
examples of somene using the stamp as a fuel injector
based on RPM and Boost pressure.

>From: "rjmca" <rjmca@w...>
>Reply-To: basicstamps@egroups.com
>To: <basicstamps@egroups.com>
>Subject: [noparse][[/noparse]basicstamps] Re: share I/O pins with IR detector
>Date: Fri, 17 Mar 2000 14:23:01 -0500
>
><< text1.html >>

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share I/O pins with IR detector

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