> 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 Isn't 150R a little low ? The receiver may not have enough gain to completely overcome that much pull-up current -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist