I need a simple circuit capable of creating pulse trains with a 38kHz carrier. Each pulse train should have 12 pulses, 600µs width, with the 38kHz carrier. There must be a pause of 3ms between each train.
At first I though I could use a 38kHz crystal for the carrier and a LM556 (Dual 555) with one timer astable at 1.2ms 50% duty cycle and the other astable for the 3ms pause. But, to my own surprise, 38kHz crystals aren't easy to find. Then I though of replacing the crystal with an LM555 astable at 38kHz.
At this point I wonder if such a circuit makes sense. Since I could create that signal with a 8-pin PIC microcontroller like PIC12F629. The circuit would be a lot smaller and much more simple (this PIC has internal 4MHz clock). I could easily change the signal updating the code. Even when using a PIC12F629 is going to be more expensive than the timers, there's no big difference really. Or I could find a cheaper PIC one-time writable.
So my question is: Am I missing something here? Can you think of any reason for staying with the timers?
At first I though I could use a 38kHz crystal for the carrier and a LM556 (Dual 555) with one timer astable at 1.2ms 50% duty cycle and the other astable for the 3ms pause. But, to my own surprise, 38kHz crystals aren't easy to find. Then I though of replacing the crystal with an LM555 astable at 38kHz.
At this point I wonder if such a circuit makes sense. Since I could create that signal with a 8-pin PIC microcontroller like PIC12F629. The circuit would be a lot smaller and much more simple (this PIC has internal 4MHz clock). I could easily change the signal updating the code. Even when using a PIC12F629 is going to be more expensive than the timers, there's no big difference really. Or I could find a cheaper PIC one-time writable.
So my question is: Am I missing something here? Can you think of any reason for staying with the timers?