Proximity sensors and the Stamp
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Posts: 46,084
I have two NPN prox sensors that are 10-30 vdc and need to interface
them to the stamp. I will be using 12 vdc to drive the prox's and a
LED/resister combo for the load(proximity sensors have to have a load
to work I guess). Questions; for the stamp to see when the prox is
tripped could I use the other side of the load(and then through the
NPN)for a path to ground? Will I have problems combining
-5v and -12v? Any help would be appreciated.
Ian
them to the stamp. I will be using 12 vdc to drive the prox's and a
LED/resister combo for the load(proximity sensors have to have a load
to work I guess). Questions; for the stamp to see when the prox is
tripped could I use the other side of the load(and then through the
NPN)for a path to ground? Will I have problems combining
-5v and -12v? Any help would be appreciated.
Ian
Comments
iphillips@s... writes:
> I have two NPN prox sensors that are 10-30 vdc and need to interface
> them to the stamp. I will be using 12 vdc to drive the prox's and a
> LED/resister combo for the load(proximity sensors have to have a load
> to work I guess). Questions; for the stamp to see when the prox is
> tripped could I use the other side of the load (and then through the
> NPN)for a path to ground? Will I have problems combining
> -5v and -12v? Any help would be appreciated.
> Ian
>
Regarding the "load" for your sensor. The sensor likely has an NPN open
collector output. This means that the collector of the NPN transistor is not
tied to anything. A user typically will tie the collector to +5 volts through
5k to 10K ohms. Therefore, when the NPN transistor is completely off, the
collector will be at 5 volts. When the NPN transistor is in saturation, the
collector will be at 0 volts (0.2 or so). This gives the user a logic 1 and
0 respectively.
Depends greatly on the sensor used. Many have an analogue output, while
others have a digital output.
If you have an analogue output, you may need to tie the collector of the NPN
side to the input of a comparator. The reference input to the comparator is
tied to a voltage level that you must determine experimentally. To determine
the reference voltage level, do the following.
Watch the output (collector) of the NPN device verses the distance
(proximity). This will give you the value for your reference voltage to the
comparator.
The output of the comparator can be wired in such a way to give you a logic 1
or a logic 0, something the stamp can easily interpret.
Enjoy. There are lots of good hardware guys that reply to this forum and will
likely give you alternate methods to achieve your desired results.
Ken
[noparse][[/noparse]Non-text portions of this message have been removed]
iphillips@s... writes:
> I have two NPN prox sensors that are 10-30 vdc and need to interface
> them to the stamp. I will be using 12 vdc to drive the prox's and a
> LED/resister combo for the load(proximity sensors have to have a load
> to work I guess). Questions; for the stamp to see when the prox is
> tripped could I use the other side of the load(and then through the
> NPN)for a path to ground? Will I have problems combining
> -5v and -12v? Any help would be appreciated.
> Ian
>
What brand and manf# sensors are you using?
[noparse][[/noparse]Non-text portions of this message have been removed]
An Omron E2E2-X5C1 ($95 CND). 2- ACI LCM1-1206P-ARU4 NPN N.O. 200ma max
($50 CND). By the time I found the second my boss had already ordered
the first. Oh well.
Ian
Original Message
From: smartdim@a... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=CrUOfoQxhJTJHUK5CWmdyyR--pRdQogBgcLrlw-KYcJxUoiYnFbLKG3eptkjJpiDOkQ5E8SBKg]smartdim@a...[/url
Sent: February 16, 2003 2:42 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Proximity sensors and the Stamp
In a message dated 2/16/2003 10:43:43 AM Pacific Standard Time,
iphillips@s... writes:
> I have two NPN prox sensors that are 10-30 vdc and need to interface
> them to the stamp. I will be using 12 vdc to drive the prox's and a
> LED/resister combo for the load(proximity sensors have to have a load
> to work I guess). Questions; for the stamp to see when the prox is
> tripped could I use the other side of the load(and then through the
> NPN)for a path to ground? Will I have problems combining
> -5v and -12v? Any help would be appreciated.
> Ian
>
What brand and manf# sensors are you using?
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output a voltage depending on the distance of the item detected? If it
simply is on or off, I would use an opto-isolator to interface it with the
Stamp -- less risk of hosing the Stamp with 12 volts.
Original Message
> I have two NPN prox sensors that are 10-30 vdc and need to interface
> them to the stamp. I will be using 12 vdc to drive the prox's and a
> LED/resister combo for the load(proximity sensors have to have a load
> to work I guess). Questions; for the stamp to see when the prox is
> tripped could I use the other side of the load(and then through the
> NPN)for a path to ground? Will I have problems combining
> -5v and -12v? Any help would be appreciated.
iphillips@s... writes:
> In the usual way things work out for me I have two different types. 1 -
> An Omron E2E2-X5C1 ($95 CND). 2- ACI LCM1-1206P-ARU4 NPN N.O. 200ma max
> ($50 CND). By the time I found the second my boss had already ordered
> the first. Oh well.
> Ian
>
>
Here is a link to the sensor you have. It shows the load connected from the
black wire to the brown wire. If you wire it like this, just as dweasal
mentioned, you will want to use an opto isolator so you don't cook your
stampl
However, that is an extra 6 pins (6pin dip package) you need to deal with for
the opto isolator.
Another approach with less pin count is to connect the load between the brown
wire and +5 volts. And the brown wire also goes to the stamp. You will get a
logic 1 and 0.
Is is necessary to use an LED in your load? If you do use an LED in your
load this arrangement may not work. It may not give you a logic 1. The reason
is as follows:
When the LED circuit has no current going through it, it is extreemly high
impeadance, somewhere about 7 meg. If the input circuit of the stamp is not
alot greater than 7 meg, you will not get a logic 1 when there is no current
going through the LED. If you must have the LED (assuming you need a visual
indication of detection) use the opto isolater suggested by dweasel. If you
need more detail on either hook up, write back.
Ken
<A
HREF="http://oeiwcsnts1.omron.com/pdfcatal.nsf/PDFLookUpByUniqueID/A0C26A2BE4F15\
19186256B0500500C8D/$FILE/D06E2E23WireDC1101.pdf">
http://oeiwcsnts1.omron.com/pdfcatal.nsf/PDFLookUpByUniqueID/A0C26A2BE4F151918
6256B0500500C8D/$FILE/D06E2E23WireDC1101.pdf</A>
[noparse][[/noparse]Non-text portions of this message have been removed]
Brown(+12v) and the other to +5v? The only thing that I am a little
confused about is how the stamp will read this with +12v going to it. I
was looking at it as just a simple pull up switch situation. Not the
case?
Original Message
From: smartdim@a... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=Obg0yd_QgRssC2XWHBfAB-5TXQbP0Z23Qm2xqw86Iw7PbfAZ4Pzuo4L6apBw37Bm1XRr3M5KiP_EXwQ]smartdim@a...[/url
Sent: February 16, 2003 4:41 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Proximity sensors and the Stamp
In a message dated 2/16/2003 11:50:02 AM Pacific Standard Time,
iphillips@s... writes:
> In the usual way things work out for me I have two different types. 1
-
> An Omron E2E2-X5C1 ($95 CND). 2- ACI LCM1-1206P-ARU4 NPN N.O. 200ma
max
> ($50 CND). By the time I found the second my boss had already ordered
> the first. Oh well.
> Ian
>
>
Here is a link to the sensor you have. It shows the load connected from
the
black wire to the brown wire. If you wire it like this, just as dweasal
mentioned, you will want to use an opto isolator so you don't cook your
stampl
However, that is an extra 6 pins (6pin dip package) you need to deal
with for
the opto isolator.
Another approach with less pin count is to connect the load between the
brown
wire and +5 volts. And the brown wire also goes to the stamp. You will
get a
logic 1 and 0.
Is is necessary to use an LED in your load? If you do use an LED in
your
load this arrangement may not work. It may not give you a logic 1. The
reason
is as follows:
When the LED circuit has no current going through it, it is extreemly
high
impeadance, somewhere about 7 meg. If the input circuit of the stamp is
not
alot greater than 7 meg, you will not get a logic 1 when there is no
current
going through the LED. If you must have the LED (assuming you need a
visual
indication of detection) use the opto isolater suggested by dweasel. If
you
need more detail on either hook up, write back.
Ken
<A
HREF="http://oeiwcsnts1.omron.com/pdfcatal.nsf/PDFLookUpByUniqueID/A0C26
A2BE4F1519186256B0500500C8D/$FILE/D06E2E23WireDC1101.pdf">
http://oeiwcsnts1.omron.com/pdfcatal.nsf/PDFLookUpByUniqueID/A0C26A2BE4F
151918
6256B0500500C8D/$FILE/D06E2E23WireDC1101.pdf</A>
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iphillips@s... writes:
> That's the right one alright. So, I attach one side of the load to the
> Brown(+12v) and the other to +5v? The only thing that I am a little
> confused about is how the stamp will read this with +12v going to it. I
> was looking at it as just a simple pull up switch situation. Not the
> case?
>
Not quite......
The diagram shows the load connected as follows....one side of the load is
connected to the black wire, the other side of the load is connected to the
+12 volt wire...this condition will give you either +12 on the black wire, or
0 volts on the black wire. +12 volts to the stamp input pin is VERY BAD.
Instead of connecting the other side of the load to +12, connect it to a +5
volt source.
The load is not connected to the +12 in any way shape or form.
So, you should end up with one end of the load connected to the black wire,
the other end of the load connected to +5 volts. The end of the load that is
connected to the black wire also goes to your stamp input pin.
In this condition, the sensor output (black wire) will be either a logic 1 or
logic 0 (5v or 0V). Again, this is without the "LED" load, just a simple
resistor about 10k ohms will work fine.
Write back if you have questions...
Ken
[noparse][[/noparse]Non-text portions of this message have been removed]
smartdim@a... writes:
> However, that is an extra 6 pins (6pin dip package) you need to deal with
> for
> the opto isolator.
> Another approach with less pin count is to connect the load between the
> brown
> wire and +5 volts. And the brown wire also goes to the stamp. You will get
> a
> logic 1 and 0.
>
I now see the confusion. I INCORRECTLY said to connect the load between the
brown and +5.....That is WRONG,
The load gets connected between the black and +5, sense the state of the
black wire.
Ken
[noparse][[/noparse]Non-text portions of this message have been removed]
They suggest using the higher voltage because it's there. Thanks again.
Ian.
Original Message
From: smartdim@a... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=7BitkxwaETdInNa6MpzBluk8l0vzQ11f7I06yBl1XtKkN1nSLxyso6pVMRb8xjv-5XOYXDeJmMiLKVA]smartdim@a...[/url
Sent: February 16, 2003 5:20 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Proximity sensors and the Stamp
In a message dated 2/16/2003 1:58:35 PM Pacific Standard Time,
iphillips@s... writes:
> That's the right one alright. So, I attach one side of the load to the
> Brown(+12v) and the other to +5v? The only thing that I am a little
> confused about is how the stamp will read this with +12v going to it.
I
> was looking at it as just a simple pull up switch situation. Not the
> case?
>
Not quite......
The diagram shows the load connected as follows....one side of the load
is
connected to the black wire, the other side of the load is connected to
the
+12 volt wire...this condition will give you either +12 on the black
wire, or
0 volts on the black wire. +12 volts to the stamp input pin is VERY BAD.
Instead of connecting the other side of the load to +12, connect it to a
+5
volt source.
The load is not connected to the +12 in any way shape or form.
So, you should end up with one end of the load connected to the black
wire,
the other end of the load connected to +5 volts. The end of the load
that is
connected to the black wire also goes to your stamp input pin.
In this condition, the sensor output (black wire) will be either a logic
1 or
logic 0 (5v or 0V). Again, this is without the "LED" load, just a simple
resistor about 10k ohms will work fine.
Write back if you have questions...
Ken
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iphillips@s... writes:
> Of course! Can't see the forest for the manuals.... I'll stop there.
> They suggest using the higher voltage because it's there. Thanks again.
> Ian.
>
You are correct, they show the load connected to the +12 because it is there.
But just to make sure you understand, that configuration will blow the input
to the stamp.
[noparse][[/noparse]Non-text portions of this message have been removed]