From: Sathe Dilip (sathe_dilip_at_bah.com)
Date: 2002-05-08 15:52:13
Hi everybody,
I too have joined recently. Don't know if this was discussed or thought
of before. Just some food for thought may be:
Considering that the signal frequency we are dealing with is quite low,
will it be possible to use the IRDA standard to send data to the PCs?
This way we automatically get the isolation. Once the hand shake is
established it may be possible to send a modulated stream of packets or
something.
Any thoughts?
Dilip
---------------------------------------------------
Joerg Hansmann wrote:
>Hi Andreas,
>
>----- Original Message -----
>From: sleeper75se <sleeper75se_at_yahoo.se>
>To: <buildcheapeeg_at_yahoogroups.com>
>Sent: Wednesday, May 08, 2002 1:59 AM
>Subject: [buildcheapeeg] Another update
>
>
>>Hmm, this place has been very quiet for a long time now.
>>
>>Time for a small update - again:
>>The serial port powered optocoupler works! It has been tested with a
>>desktop PC serial port and an RS232-to-USB converter (Palm USB kit).
>>I will test on a laptop as soon as I get my hands on one.
>>
>>The schematic is uploaded to
>>
>>http://groups.yahoo.com/group/buildcheapeeg/files
>>
>>under hardware design/RS232TX
>>
>
>I have just downloaded it and have a few questions:
>
>What total current / power consumption does the circuit have ?
>And what maximum baud rate ?
>
>What happens at increased temperatures e.g. 60 degrees Celsius ?
>
>Probly nothing, because you are using quite high photo currents
>up to 30uA.
>
>I am only asking because recently I have tried to build a POF
>receiver based on your 2 transistor design (slightly modified,
>9600baud and ca. 10m fiber length) and ran into some difficulties
>at higher temperatures because the reverse current through
>the photo-diode increased and got greater than the photocurrent.
>
>(In the attachment is a schematic of a 1 op-amp solution with
>thermal compensation, that should work with 500nA photocurrent
>and up to 115200 baud. The simulation does not work as expected,
>because the TL071 model file from TI is definitely wrong (10 times
>supply current and 1/20 slew rate))
>
>
Snipped
This archive was generated by hypermail 2.1.4 : 2002-07-27 12:28:43 BST