Inverting things
To tackle the problem of turning off the IR beacon while the IR transmission was taking place, I typed words into Google and started finding some good stuff when I searched for "digital inversion circuit".
I read a bit about switching regulators such as the MC34063 but quickly became intimidated. It seemed like more than I needed.
Eventually I found a page on Sparkfun that talked about transistors and NOT gates. I ended up building this circuit using a NPN transistor, some resistors, and a capacitor. The Sparkfun page lacked actual resistor values so I sorta guessed at them.
The 10uF capacitor maintains a voltage on the NPN base while the yellow LED is flashing, which I think is going to be important for my application.
Scrubbing through the video on my phone, I was able to find a frame where both the yellow and red LEDs are illuminated. Not too surprising, really, but it makes me wonder how feasible it is to get an LED to turn off during the milli-second timeframes that are involved in IR signals. One hack that occurred to me was to set the IR transmission pin to high, for some short time before I send the actual signal (I think that most IR protocols do something like this, anyway).
I found this page on Wikipedia, on using diodes to speed-up the switching of a transistor.
I remembered that I bought the Art of Electronics a while back and barely looked at it. It's not the sort of book you just flip open and find the answer to your problem, not without an understanding of the fundamentals.
Anyway, some testing should indicate whether I'm on the right track or will need to take an entirely different approach. And, once again, I'm wishing for a scope.
I read a bit about switching regulators such as the MC34063 but quickly became intimidated. It seemed like more than I needed.
Eventually I found a page on Sparkfun that talked about transistors and NOT gates. I ended up building this circuit using a NPN transistor, some resistors, and a capacitor. The Sparkfun page lacked actual resistor values so I sorta guessed at them.
The 10uF capacitor maintains a voltage on the NPN base while the yellow LED is flashing, which I think is going to be important for my application.
Scrubbing through the video on my phone, I was able to find a frame where both the yellow and red LEDs are illuminated. Not too surprising, really, but it makes me wonder how feasible it is to get an LED to turn off during the milli-second timeframes that are involved in IR signals. One hack that occurred to me was to set the IR transmission pin to high, for some short time before I send the actual signal (I think that most IR protocols do something like this, anyway).
I found this page on Wikipedia, on using diodes to speed-up the switching of a transistor.
I remembered that I bought the Art of Electronics a while back and barely looked at it. It's not the sort of book you just flip open and find the answer to your problem, not without an understanding of the fundamentals.
Anyway, some testing should indicate whether I'm on the right track or will need to take an entirely different approach. And, once again, I'm wishing for a scope.
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