After moving into a new apartment I was faced with a full set of white-hot, inefficient halogen ceiling bulbs. The fixtures use the 12 volt DC MR16 standard, taken from the mains after being converted from 120 AC. They’re controlled by the light switch right next to the front door, making them essential for navigating a dark room when first arriving home.
While there are LED alternatives on the market for this socket type, the technology is still prohibitively expensive. I pulled one of the halogens and found the socket was simply two pieces of 19 gauge wire. I decided to free-form some circuits made of different colored LEDs around the thicker terminals.
Depending on the color and the amount of LEDs used in a circuit, the resistance needs change. Unless you’re an electrical engineer, you’ll probably find that an online LED circuit calculator comes in handy.
Once you have them all soldered together, check the polarity on each fixture with a test circuit. The fixtures are designed to only work with a load, so I used a small DC motor and noted the proper direction of rotation. Then, with the lightswitch turned off, carefully plug the 19 gauge wires into the sockets and switch them on.
The result is a soft and ambient illumination that lights my way when coming home. If I need it brighter I switch on some lamps in the room.