Infrared remote control repeater circuit

I've built the circuit shown at the following link:

http://www.mitedu.freeserve.co.uk/Circuits/Interface/irext5.htm

However, I seem to be having a problem regarding ambient light. I did
make one change to the circuit. Since I couldn't find the SFH2030 IR
detector diode, I used a Vishay BPV22NF with a daylight filter. Also,
it might be worth noting that I used a wall wart to power the device
instead of a battery. Anyway, the only way I can get the device to
work is to completely turn all of the lights off in the room. Is there
some way to get this to operate so that the circuit is insensitive to
ambient light such as daylight and 60 Hz lighting? I'm new to IR
circuits, but I'm guessing that this has something to do with the
reverse bias levels on the IR detector diode, but I'm not sure. Any
help would be appreciated.

The reason I select this circuit was because I thought it was less
prone to the effects of ambient light.

 

Well, I usually use the Panasonic IR detectors with the filtering and
TTL logic as a unit. PNA4612 38.0 KHz running into a microcontroller. I
looked at Andy's circuit and I don't see any reverse bias on the
photodioide. If the opamp is functioning correctly, both inputs should
be at the same DC level meaning 0 bias on the diode. Photo diodes have
better speed and linearity with some reverse bias on them but then have
dark current issues. It would seem to me that the signal should be AC
coupled to reduce ambient light sensitivity. You're only interested in
the pulsing. Just curious, how much range are you trying to get?
GG

 

I'm looking for a range of about 15 to 20 feet. That works fine as
long as the lights are out and ambient light is very minimal. I tried
inserting a coupling capacitor between the diode and the opamp input,
but it didn't help much.


stratus46@yahoo.com wrote:

Well, I usually use the Panasonic IR detectors with the filtering and
TTL logic as a unit. PNA4612 38.0 KHz running into a microcontroller.
I
looked at Andy's circuit and I don't see any reverse bias on the
photodioide. If the opamp is functioning correctly, both inputs
should
be at the same DC level meaning 0 bias on the diode. Photo diodes
have
better speed and linearity with some reverse bias on them but then
have
dark current issues. It would seem to me that the signal should be AC
coupled to reduce ambient light sensitivity. You're only interested
in
the pulsing. Just curious, how much range are you trying to get?
GG

 

Well, that makes sense. Thanks for your help.


John Smith wrote:

I can't seem to find a datasheet for the SFH2030, but found this:
http://www.maplin.co.uk/Module.aspx?ModuleNo=2242
where it says that the device can be used either as a photodiode
(with
suitable reverse biasing), or as a photovoltaic cell. I suspect your
circuit
is using it as the latter.
The datasheet for the Vishay part doesn't mention the same
capability.


jondoeengineer@hotmail.com> wrote in message
news:1113686696.583964.284670@l41g2000cwc.googlegroups.com...
I've built the circuit shown at the following link:

http://www.mitedu.freeserve.co.uk/Circuits/Interface/irext5.htm

However, I seem to be having a problem regarding ambient light. I
did
make one change to the circuit. Since I couldn't find the SFH2030
IR
detector diode, I used a Vishay BPV22NF with a daylight filter.
Also,
it might be worth noting that I used a wall wart to power the
device
instead of a battery. Anyway, the only way I can get the device to
work is to completely turn all of the lights off in the room. Is
there
some way to get this to operate so that the circuit is insensitive
to
ambient light such as daylight and 60 Hz lighting? I'm new to IR
circuits, but I'm guessing that this has something to do with the
reverse bias levels on the IR detector diode, but I'm not sure.
Any
help would be appreciated.

The reason I select this circuit was because I thought it was less
prone to the effects of ambient light.

 

Samsung and Sony remotes with the PNA4612 receiver easily reach 15-20
feet, more like 25+. You do have to point it at the receive module but
it is fine in normal room lights and during the day, provided direct
sun is not on the receiver. Are you trying to get around obstacles? My
HDTV Wonder came with the ATI remote wonder. This is an RF unit, not
IR. I still have this urge to 'point' it at the computer but it makes
no difference.
GG