If you do pulse the LED, then the input on the pic pin will also be pulsed. Why have you not already tried this? You will need to decrease the value of the curmit limitting resistor to increase brightness when you pulse LED. What would happen if you used 2 pic pins to drive the LED. One on steady and the other pulsed. Then would have best of both worlds. Bill ----- Original Message ----- From: "Jamie Jensen" <j_j_140909@YAHOO.COM> To: "pic microcontroller discussion list" <PICLIST@mitvma.mit.edu> Sent: Monday, November 28, 2005 10:48 AM Subject: [EE] IR detector interface >I have a circuit im breadboarding so I am transmitting a IR puslse to a >open collector type reciever, being used to align two devices If I connect >the emitter to ground, then have a 150ohm pullup on the collector, I can >see the voltage on the PIC input range from no IR signal of 5V, and down to >about half a volt when i position the IR tx diode just right. > > So, question is, in order to increase the range can I simply burst pulse > the LED with the max current (right now 30mA but it can accept up to 50mA) > or change the pull up resistor to change the sensitivity? Does my > question make sense? In other words, I see a range from 200 to 255 but > I'd like to see the transistor turn on harder to pull it more to ground so > which makes sense to do. > > JJ > > > --------------------------------- > Yahoo! Music Unlimited - Access over 1 million songs. Try it free. > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist