I have used 2 pins of a pic to do this job: (PIC16F872) at 4Mhz
One was a PWM output at 38kHz, 1:2 duty cycle
Second was UART-TX pin at 1900 or other rate, don't remember, to provide
the "data"

IR LED was driven with 2 NPN transistor (numeric one from On Semi: ).
It's a 3 year old design, i have to look after the schema.
It's work fine. I have used a IR receiver from vishay (TSOP1838) because
of his 3.3V capacity.Attention of the 150ms gap in the transmission that
the photomodule need to work properly. Have a look at app notes at
vishay website.

SamB

-----Message d'origine-----
De : pic microcontroller discussion list [mailto:PICLIST@MITVMA.MIT.EDU]
De la part de Debbie Hynes
Envoy=E9 : mardi 20 janvier 2004 08:40
=C0 : PICLIST@MITVMA.MIT.EDU
Objet : [EE:] IR modulator schematic?


PICers - i'm looking round for ideas to build an IR modulator cct. did a
quick google but mostly fopund IR receivers.

I'm using a 16f84 to drive an IR led but i'll need to modulate it at
38kbps. i guess i could use a 555 to gate the LED on/off - any other
ideas?

thankz 4 advice

best - Debbie :)

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