stamp II and IR emitter/detector
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I am trying to use a fairchild qrb1134 emitter/detector with my bsII
for a line sensing robot. The sensor has a total of four lines:
cathode,anode,emitter,detector. I have the + and gnd hooked up
and the detector is obviously an input on the stamp, but what
about the emitter? Do I use the freqout command to have it send
out a specific signal? I have tried to do this using 38.5K as the
output frequency but have come up empty. Any ideas are
appreciated.
for a line sensing robot. The sensor has a total of four lines:
cathode,anode,emitter,detector. I have the + and gnd hooked up
and the detector is obviously an input on the stamp, but what
about the emitter? Do I use the freqout command to have it send
out a specific signal? I have tried to do this using 38.5K as the
output frequency but have come up empty. Any ideas are
appreciated.
Comments
You don't need to modulate the emitter to get the detector to pick it up.
What you need is a comparator IC like a LM339. Use either the - or the +
input connected to the detector (the detector is also open collector, you
you'll need a 10k resistor to V+ as well), then use the other - or + input
connected to the wiper on a 1k or 5k potentiometer, with the other ends
going to V- and V+ respectively.
Then you adjust the pot to get your sensitivity.
What makes this neat, is you can tie the outputs from several detectors to
the one input on the LM339, and use several I/O port pins going to each
emitter separately. Then you fire each emitter one at a time and check the
output from the LM339 to see if it went low or high depending on whether
your over a white or black area.
The LM339's - input causes the output to be inverted, whereas the + inpout
is non-inverting. There are several other types of comparators you could use
as well, besides a LM339, but it is easy to get, and you don't have to do
anything with the comparators you don't need.
Original Message
From: mrscience509 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=NtGAcPWI8VWXhMyG0VygSLB4HsSasIRx1iEGEHhxaHZMt0kOywIS2hO1HWJgtzRLh2d1C2Fy8Z2nPvOO]mrscience509@y...[/url
Sent: Saturday, May 11, 2002 5:31 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] stamp II and IR emitter/detector
I am trying to use a fairchild qrb1134 emitter/detector with my bsII
for a line sensing robot. The sensor has a total of four lines:
cathode,anode,emitter,detector. I have the + and gnd hooked up
and the detector is obviously an input on the stamp, but what
about the emitter? Do I use the freqout command to have it send
out a specific signal? I have tried to do this using 38.5K as the
output frequency but have come up empty. Any ideas are
appreciated.
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and use another pin for the detector. This is the generic method I use for
the Fairchild sensors. You may have to juggle the 10k resistor value a bit
to get good results.
********
Connect one lead of a 270 ohm resistor to +5 volts. Connect the other side
of the resistor to the A (anode) terminal of the emitter (documentation says
it the orange wire).
Connect the K (cathode) terminal of the emitter (documentation says its the
green wire) to a Stamp pin. Set the Stamp pin to output and set it LOW to
turn on the LED. If you need to modulate the emitter (not really needed as
detector is not looking for a modulated signal) you can use PULSOUT.
Note: If you don't want to be able to turn the emitter on and off you can
wire the K terminal to ground instead of to the Stamp pin.
Connect one lead of a 10k resistor to +5 volts. Connect the other lead of
the resistor to the C (collector) terminal of the detector (documentation
says its the white wire).
Connect the E (emitter) terminal of the detector (documentation says the
blue wire) to ground.
Connect one lead of a 270 ohm resistor to the C terminal and the other lead
to a Stamp pin. Set the Stamp pin for input. The pin should read high when
there is something reflecting the light from the emitter to the detector.
You can also wire the C terminal directly to the Stamp pin, but the resistor
serves to protect things from code errors.
Original Message
> I am trying to use a fairchild qrb1134 emitter/detector with my bsII
> for a line sensing robot. The sensor has a total of four lines:
> cathode,anode,emitter,detector. I have the + and gnd hooked up
> and the detector is obviously an input on the stamp, but what
> about the emitter? Do I use the freqout command to have it send
> out a specific signal? I have tried to do this using 38.5K as the
> output frequency but have come up empty. Any ideas are
> appreciated.
Now may I ask for the same procedure using a Sharp GP2D12
IR emitter/detector?
Thanks again.
Al
--- In basicstamps@y..., Rodent <daweasel@s...> wrote:
> If you only have one sensor you can easily fire the emitter with
a Stamp pin
> and use another pin for the detector. This is the generic
method I use for
> the Fairchild sensors. You may have to juggle the 10k resistor
value a bit
> to get good results.
>
> ********
>
> Connect one lead of a 270 ohm resistor to +5 volts. Connect
the other side
> of the resistor to the A (anode) terminal of the emitter
(documentation says
> it the orange wire).
>
> Connect the K (cathode) terminal of the emitter (documentation
says its the
> green wire) to a Stamp pin. Set the Stamp pin to output and set
it LOW to
> turn on the LED. If you need to modulate the emitter (not really
needed as
> detector is not looking for a modulated signal) you can use
PULSOUT.
>
> Note: If you don't want to be able to turn the emitter on and off
you can
> wire the K terminal to ground instead of to the Stamp pin.
>
> Connect one lead of a 10k resistor to +5 volts. Connect the
other lead of
> the resistor to the C (collector) terminal of the detector
(documentation
> says its the white wire).
>
> Connect the E (emitter) terminal of the detector (documentation
says the
> blue wire) to ground.
>
> Connect one lead of a 270 ohm resistor to the C terminal and
the other lead
> to a Stamp pin. Set the Stamp pin for input. The pin should
read high when
> there is something reflecting the light from the emitter to the
detector.
> You can also wire the C terminal directly to the Stamp pin, but
the resistor
> serves to protect things from code errors.
>
>
Original Message
>
> > I am trying to use a fairchild qrb1134 emitter/detector with my
bsII
> > for a line sensing robot. The sensor has a total of four lines:
> > cathode,anode,emitter,detector. I have the + and gnd hooked
up
> > and the detector is obviously an input on the stamp, but what
> > about the emitter? Do I use the freqout command to have it
send
> > out a specific signal? I have tried to do this using 38.5K as
the
> > output frequency but have come up empty. Any ideas are
> > appreciated.
Original Message
> Thanks, this method worked very well, you saved my project.
>
> Now may I ask for the same procedure using a Sharp GP2D12
> IR emitter/detector?