RE: Re: Electronics Question

["Keith Doxey" <lists.diyha@xxxxxxx>]

Yep that would work but normally the LED would be fed from +5v and grounded by the TTL. They have better sink than source capability. You would then need to reverse the opto-transistor side. Pull up resistor grounded by the transistor.

 

Do you have ADSL ?

 

If not you will appreciate that some of use are on ISDN or lower.....save it as a GIF.

 

626Kb ........ bloody hell !!!!

 

At least you didnt post it to the list ;-)

 

Keith

-----Original Message-----
From: poulton_s [mailto:swp@xxxxxxx]
Sent: 26 February 2002 18:29
To: ukha_d@xxxxxxxSubject: [ukha_d] Re: Electronics Question

Hi All,

Can someone take a look at

http://ha.fluidvisions.net/misc/opto.bmp

Obviously ground on the left of the opto is NOT the same as on the
right.

I'm trying to convert TTL serial to RS232 with opto isolation to
avoid ground troubles.


Cheers

Stuart


--- In ukha_d@y..., "Keith Doxey" <lists.diyha@b...> wrote:
> Will work fine but remember that the two halves of the circuit must
be
> powered from different power supplies otherwise you dont have
isolation.
>
> Keith
>   -----Original Message-----
>   From: Stuart Poulton [mailto:swp@s...]
>   Sent: 26 February 2002 14:03
>   To: ukha_d@xxxxxxx>   Subject: RE: [ukha_d] Electronics Question
>
>
>   Ok, time to ask for more help.
>
>   I need to opto isolate serial signal, for reasons which will
become
>   apparent, if I say that the project in question is related to a
phone
>   connection.
>
>
>   So heres what I think I need, remeber serial is only 1200 BPS
>
>
>
>   TTL Signal--------Opto-isolator-------MAX232-------PC Serial Port
>
>   Cheers
>
>   Stuart
>
>
>
>
>
>   On Sun, 2002-02-24 at 22:21, Ian B wrote:
>   > Look on my site for a piccy of just that and with 2 wire LCD if
wanted.
>   > Circuit diagram and PCB layout available if you want them (and
even in
>   > Proteus)
>   >
>   > Ian
>   >   -----Original Message-----
>   >   From: Keith Doxey [mailto:lists.diyha@b...]
>   >   Sent: 24 February 2002 09:23
>   >   To: ukha_d@xxxxxxx>   >   Subject: RE: [ukha_d] Electronics Question
>   >
>   >
>   >   The MAX232 I posted to the list yesterday includes voltage
doublers
> and
>   > converters all in a single 16pin DIP.
>   >
>   >   In fact I was building a test board last night with a MAX232
and PIC
>   > 16F628.
>   >
>   >   Keith
>   >     -----Original Message-----
>   >     From: Dr John Tankard [mailto:john@s...]
>   >     Sent: 24 February 2002 06:50
>   >     To: ukha_d@xxxxxxx>   >     Subject: RE: [ukha_d] Electronics Question
>   >
>   >
>   >     > Hi,
>   >     >
>   >     > I'd like to take a data signal clocked at 1200 Baud, from
a
> battery
>   >     > powered deivce (power is 3x1.5V AAA) for connection to a
>   >     > serial input at
>   >     > either 5V or RS232 levels, any suggestions on the best
way to do
> this.
>   >     >
>   >     > Note I only need to read the data.
>   >
>   >     I assume the question you are asking is how do I get the
required
>   >     voltage to run rs232 ? If that is what you want then you
could look
> at a
>   >     DC-DC converter, mamim do them from memory
>   >     http://dbserv.maxim-ic.com/PowerSupplies.cfm
>   >
>   >     Or if you don't heed a higher voltage for any other parts
of you
> design
>   >     you could look at a rs232 driver with voltage conversion
built in.
> Again
>   >     Maxim do loads of theses but I can't remember the part
numbers, take
> a
>   >     look on the same site under interface.
>   >
>   >     John
>
>
>
>   For more information: http://www.automatedhome.co.uk
>   Post message: ukha_d@xxxxxxx>   Subscribe:  ukha_d-subscribe@xxxxxxx>   Unsubscribe:  ukha_d-unsubscribe@xxxxxxx>   List owner:  ukha_d-owner@xxxxxxx>
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