input pin voltage
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In a message dated 11/02/2002 18:19:37 Eastern Standard Time,
mpowell@t... writes:
> What I would like to know is will 6 volts input damage my bs2p stamp. I have
> A fiberoptic xmit and recive amplifer and the min. voltage it will work at
> is 6 volts on its amp. I want to pull the stamp pin low when dark but when
> not dark I recive the 6 volts from the fibroptic amp. to the stamp pin.How
> do I fix this problem A series resistor??
> thanks any help will be greatley appreciated THANKS
>
A voltage divider would be preferable. The voltage across a series resistor
varies with the current through it.,
Sid
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mpowell@t... writes:
> What I would like to know is will 6 volts input damage my bs2p stamp. I have
> A fiberoptic xmit and recive amplifer and the min. voltage it will work at
> is 6 volts on its amp. I want to pull the stamp pin low when dark but when
> not dark I recive the 6 volts from the fibroptic amp. to the stamp pin.How
> do I fix this problem A series resistor??
> thanks any help will be greatley appreciated THANKS
>
A voltage divider would be preferable. The voltage across a series resistor
varies with the current through it.,
Sid
[noparse][[/noparse]Non-text portions of this message have been removed]
Comments
fiberoptic xmit and recive amplifer and the min. voltage it will work at is 6
volts on its amp. I want to pull the stamp pin low when dark but when not dark
I recive the 6 volts from the fibroptic amp. to the stamp pin.How do I fix this
problem A series resistor??
thanks any help will be greatley appreciated THANKS
MAX
[noparse][[/noparse]Non-text portions of this message have been removed]
Original Message
From: <Newzed@a...>
To: <basicstamps@yahoogroups.com>
Sent: Saturday, November 02, 2002 3:21 PM
Subject: Re: [noparse][[/noparse]basicstamps] input pin voltage
> In a message dated 11/02/2002 18:19:37 Eastern Standard Time,
> mpowell@t... writes:
>
>
> > What I would like to know is will 6 volts input damage my bs2p stamp. I
have
> > A fiberoptic xmit and recive amplifer and the min. voltage it will work
at
> > is 6 volts on its amp. I want to pull the stamp pin low when dark but
when
> > not dark I recive the 6 volts from the fibroptic amp. to the stamp
pin.How
> > do I fix this problem A series resistor??
> > thanks any help will be greatley appreciated THANKS
> >
>
> A voltage divider would be preferable. The voltage across a series
resistor
> varies with the current through it.,
>
> Sid
>
>
> [noparse][[/noparse]Non-text portions of this message have been removed]
>
>
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> What I meant to say in earlier mess is I am already using A 10k for pull
down on input if I add A 2k in series with the 10k and connect the stamp
pin between the 2k and the 10k this would give me my 5 volts but would there
be enough current flow for the stamp pin to operate properley.
thanks for info
max
>
>
The right way to do this is t use a thing called an opto-osolator. Use a
4N35. (THIS IS ASSUMING YOUR FIBER 6 VOLT SIGNAL WILL SUPPLY 10 TO 15 MA WHEN
AT 6 VOLTS!!!!!!!!!!!!!)
This is an infrared emitter detector in a 6 pin DIP package.
There is an infrared LED and a NPN transistor triggered by the IR LED.
Use your 6 volt signal on the "diode" side and interface the NPN transistor
to the stamp.
You can easily find the data sheet on the web, just search on 4N35.
Therefore connect a 470 ohm resistor to your 6 volt signal. The other end of
the resistor goes to pin 1 of the 4N35, and pin 2 of the 4N35 to ground. In
this config, when you get 6 volts, the IR diode will "emit" its IR signal.
Now for the rest, NPN transistor. Connect pin 4 to ground. Connect pin 6 to
ground through a 1k to 10 resistor (use 1k if the switching frequency will be
high, otherwise 10k will sufice). Connect pin 5 as follows.....Pin 5 will
have a 10k resistor connected to +5 volts. Also, connect pin 5 to the BS2
input pin.
This is what will happen....when your fiber optic circuit is "low", no IR
energy emitted, the NPN transistor is off and the stamp will see 5 volts.
When your fiber circuit gets 6 volts, it will emit IR energy, the transistor
will turn on and the stamp will see a "low", less than 0.5 volts...
The beauty of this opto-isolator is that it is a very clean way to convert
one voltage level to another level, you just need to remember that the signal
is inverted, that is when the input is high the output is low and visa versa,
easy to handle with software code.
Regarding the "diode" part. Regardless of what dc voltage is the input this
can be used, you simply set the input current for 10 to 25 mA my doing the
following. Subtract 1.5 volts from the input signal (6 volts in your case...
6 - 1.5 = 4.5) and use this value to set the current......4.5 volts/10mA =
450 ohms (470 close enough). Makes sense????? I have done this several
times, it works!!!!!!!1
[noparse][[/noparse]Non-text portions of this message have been removed]
> > What I meant to say in earlier mess is I am already using A 10k for pull
>down on input if I add A 2k in series with the 10k and connect the stamp
>pin between the 2k and the 10k this would give me my 5 volts but would there
>be enough current flow for the stamp pin to operate properley.
Yes. This is an easy solution and will work just fine.
dwayne
--
Dwayne Reid <dwayner@p...>
Trinity Electronics Systems Ltd Edmonton, AB, CANADA
(780) 489-3199 voice (780) 487-6397 fax
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