Outdoor Path Lighting
When my wife and I moved into our present house we natually made some changes. The previous owners had installed some low voltage lighting along the walkway from the front door to the circular driveway. We changed out those ugly fixtures, and added additional ones along the driveway, using several "Malibu" light kits from Home Depot. These plastic fixtures eventually fell victim to the weed wacker - edge trimmer used by the guy who cuts our grass, and needed replacement.
At first I tried 3D printing some new ones, but the 3D printer plastic wasn't any more durable than the ones they replaced. Finally, I came up with the idea of making new lamps out of inverted glass jars and metal conduit pipe.
At first I tried 3D printing some new ones, but the 3D printer plastic wasn't any more durable than the ones they replaced. Finally, I came up with the idea of making new lamps out of inverted glass jars and metal conduit pipe.
The jars are 4oz Ball Jelly Mason jars with the provided lids and rings. I punched 1" holes in the lids to accept conduit clamp mounts for the 15" upright pipes made from 3/4" conduit. The bottoms of the pipes are hammered flat and hack sawed to a point so they can be pushed into the ground. A hole is drilled in the side near the bottom for the wire to exit.
The light is provided by a 1W white LED chip soldered to a piece of PC board that acts as a heatsink. A dab of white thermal compound is placed between the bottom of the LED and the board. Power is supplied by a bridge rectifier (in line hidden in the pipe), a 100uf 20v capacitor, a 5v (7805) regulator, and a 6.8 ohm 2 w series resistor. The resistor limits the current through the LED to 250ma (it's rated at 350ma). I had two of the LED's fail so far in a few weeks. One I know I overheated while soldering, the other may be just a statistical early failure. If any more fail, I'll consider increasing the value of those 6.8 ohm resistors to 10 ohms. This would reduce the current to about 180ma. Even at that lower level, there is plenty of light output. (Those Chinese LED's are probably sold with over-rated currrent limits. Better to run them at about 1/2 their rated current for long life!). The regulator IC and filter capacitor are mounted to the lid with JB weld epoxy, the pc board is attached with hot melt glue, as are the lids to the rings. Finally, the tops which are hot glued to the jars were 3D printed. |