原文
For output, connect an IR LED and appropriate resistor to PWM output pin 3. Make sure the polarity of the LED is correct, or it won't illuminate - the long lead is positive. I used a NTE 3027 LED (because that's what was handy) and 100 ohm resistor; the range is about 15 feet. For additional range, you can amplify the output with a transistor.
The transmission code is straightforward. To ensure accurate output frequencies and duty cycles, I use the PWM timer, rather than delay loops to modulate the output LED at the appropriate frequency. (See my Arduino PWM Secrets article for more details on the PWM timers.) At the low level, enableIROut sets up the timer for PWM output on pin 3 at the proper frequency. The mark() method sends a mark by enabling PWM output and delaying the specified time. The space() method sends a space by disabling PWM output and delaying the specified time.
发表于 2013-1-30 14:13:49
发表于 2013-1-30 19:31:56