As you might have noticed, the 38-KHz pulse generator is built around the evergreen timer chip NE555P (IC1). Here, the RC components (R5-C3-P1) set the astable frequency to drive the infrared light ...

Photography is great, but sometimes it can get boring just reusing the same wavelengths over and over again. There are other options, though and when [Malcolm Wilson] decided he wanted to explore them ...