Yup, one of these days I will get a PIC Nigel :lol:
I think I figured out why it's not working. On my oscilloscope, I realized that the LED is not turning all the way off. Look at the picture of the square wave. Since the LED is connected to pin 3 and the +9v supply, the lower pin 3 goes, the harder the LED is on.
I am getting 3.4v low peaks, and 5.2v high peaks. Even at 5.2v, the LED is still on because the voltage across the LED equals 3.8v, plenty to turn it on.
Yes, I know this is strikingly obvious, but I just got my oscilloscope and am getting used to it, and this is my first 555 project. So what do you recommend I do?