It's been a little while since I updated the site. I've had a lot going on. There are a number of new builds I will be posting in the coming weeks. This is about the latest. Problem: At night, when I read in bed and my wife is trying to sleep, the lamp on the night stand is kinda bright and obnoxious and, even though she says it doesn't, the light disturbs her. I had been using a little USB-powered LED lamp that I bought for my laptop on long night time airplane rides. However, I can't charge my iPhone while I'm using that light. Only one USB cable available at the night stand. Also, that light isn't quite bright enough for my liking. What to do?
Build a reading lamp out of stupidly bright and nearly stupidly tiny LEDs.
Here is the proof print for the light's PCB which will be mounted on the end of a flexible "gooseneck" that will extend from the night stand or from the headboard of our as yet unbuilt bed:
Notice the little pure white LED. It is actually three little LEDs in a single surface-mount package. There will be six of these around the circle. The circuit will be able to control six sets of three LEDs at a time, allowing for a cheezy ability to "dim" the light. The button that controls the circuit will be able to turn on from three to 18 LEDs in three-LED increments. It's a rough approximation of dimming without needing to use PWM (pulse width modulation). Nice and simple.
Here are two of these LEDs lit up on the breadboard (one is blue, one is pure white):
That other stuff behind the LEDs toward the top of the photo are for another project that is based on an AVR microcontroller. Pay no nevermind to those things. Stare into the light.
I have a box full of orphaned wall wart transformers. I snipped the end off of one that claims to be 9V and supplies about 500 mA of power. When I test the leads with the digital multimeter, it reads about 15V. Neat. So, I threw a 7812 12V voltage regulator on the board with a 100μF cap to keep it smooth. I'll build the switching stuff later.
I just wanted to get something up for you guys to look at, since I've neglected this thing for a couple of months.