While waiting for parts to arrive to build a proper optical serial interface, I really wanted to get some screenshots off of my oscilloscope. Knowing that the infrared LED in the interface is directly transmitting the serial signal, I figured I should be able to tap into that driving signal to obtain the serial information.
I have a Fluke ScopeMeter 97 that's come in really handy over the years. Before I got it, it was a sales rep's demo unit, so it was used pretty hard. The screen backlight is an electroluminescent panel, and their intensity can fall off pretty dramatically over it's life. This particular display is also transflective, which makes it extremely readable under direct sunlight, but means the backlight is essential to using it in indoor lighting. To use it in the past, I'd shine a bright desk light on it, but I've always wished the backlight would just work.