K
Kamus of Kadizhar
Guest
I've build a couple of the IR receivers shown here
http://www.lirc.org/receivers.html but now I'd like to get a little
fancier.
Mostly, I'd like to add 2 LEDs, one that turns on when the serial port is
activated, and the other when the receiver gets a signal.
I located some 5V LEDs (they have an internal resistor, pretty neat) and
tried to add them in a way that makes sense to me.
Since the voltage regulator provides a nice steady 5V, I connected one LED
across pins 2 and 1 of the TSOP. That works fine; the LED comes on when
the circuit is energized.
The signal received LED is a bit more problematic; the TSOP holds pin 3
high when inactive, and drops pin 3 to ground when a signal is received,
an LED across pins 2 and 3 should work. But when I try that, I get a
latching effect - once the LED comes on, sometimes it latches and stays
on. The circuit won't receive any more signals either. I thought perhaps
the LED, being so close, might be sending enough IR out to mess with the
receiver, but adding shielding did not help.
I thought this might be some excessive current drain, so I disconnected
the LED between pins 1 and 2, but the latching effect stayed.
I played around with it a bit, but then decided I did not know enough
about this sort of stuff.
So, any suggestions for modifying the circuit to add a power on and signal
LED?
FWIW, the 5V LEDs are Chicago Miniature part no. 4302Hn-5V or 12V, and
they come in different colors (the n is the color code, 1 for red, 5 for
green.)
TIA,
Yan
http://www.lirc.org/receivers.html but now I'd like to get a little
fancier.
Mostly, I'd like to add 2 LEDs, one that turns on when the serial port is
activated, and the other when the receiver gets a signal.
I located some 5V LEDs (they have an internal resistor, pretty neat) and
tried to add them in a way that makes sense to me.
Since the voltage regulator provides a nice steady 5V, I connected one LED
across pins 2 and 1 of the TSOP. That works fine; the LED comes on when
the circuit is energized.
The signal received LED is a bit more problematic; the TSOP holds pin 3
high when inactive, and drops pin 3 to ground when a signal is received,
an LED across pins 2 and 3 should work. But when I try that, I get a
latching effect - once the LED comes on, sometimes it latches and stays
on. The circuit won't receive any more signals either. I thought perhaps
the LED, being so close, might be sending enough IR out to mess with the
receiver, but adding shielding did not help.
I thought this might be some excessive current drain, so I disconnected
the LED between pins 1 and 2, but the latching effect stayed.
I played around with it a bit, but then decided I did not know enough
about this sort of stuff.
So, any suggestions for modifying the circuit to add a power on and signal
LED?
FWIW, the 5V LEDs are Chicago Miniature part no. 4302Hn-5V or 12V, and
they come in different colors (the n is the color code, 1 for red, 5 for
green.)
TIA,
Yan
