I have a small circuit board to generate a PWM signal that tells the TPS61187 LED driver chip how bright to illuminate the LED of a backlight I salvaged from a cracked LG laptop LCD screen model LP133WF2(SP)(A1). It’s not the most compact thing I could have built, but it was simple and quick. Or at least it was supposed to be quick, because my first attempt at installing it destroyed a solder connection to the screen control board and I had to redo my soldering joints and secure them with hot glue in the hopes I wouldn’t destroy any more solder connections.
Now I’m installing the circuit board again, and I realized I forgot a very important detail: The location I wanted to mount this thing is on the metal frame of this backlight, because I didn’t want to block any light that might emit from the plastic back side of the panel. My circuit board had many soldered connections on the bottom. Putting soldered connections on a metal plate causes short circuits! Fortunately I realized this before destroying anything.
Adding to the bulk of this project, I placed a sheet of clear plastic packing tape as the first layer of insulation, followed by two layers of double-sided foam tape to raise it off the first layer. The foam tape wasn’t as secure as I had hoped, so I warmed up the hot glue gun again to squirt out some secure standoffs. Thanks to the first layer of clear packing tape, I’m semi-confident I can replace this with a different PWM generator if I decide to do so in the future. But for the moment I have completed all electrical work for this light panel that I can power off USB. A happy end result of a lot of very useful and valuable electronics lessons learned building this project. From reading datasheets and their schematics to figuring out what to do when things go wrong.
But the happy result does have one downside. When I have a failure, I can dispose of the pieces after thanking them for their valuable lessons. But when I have a success, I can’t just throw it out! So now I have a ~15″ diagonal rectangular LED light and I need to think of something useful to do with it.