Easy Electronics DIY Projects

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Tuesday, April 5, 2011

EASY BAMBOO TABLE-LAMP

It was while putting up some bamboo arches and frames for creepers in the garden that an idea occurred to me--why not try and make an easy "eco-friendly" table-lamp? It would make a nice 'Vishu' present to the "significant other" in your life too! You just can't beat the combination of energy efficiency and eco-friendliness, not to say anything about the less than shoe-string budget!

I just picked up a couple of pieces of bamboo offcuts, which, after cutting, was about a foot long. To go with our "easy" tag, I hit upon a simple shape that involved no "heavy engineering" or joints or pivots or other complicated stuff. The geometry was simple and somewhat like a vertical lamp-post, with the LEDs on a disc that was at 45 degrees angle so that it threw a good beam onto the table. The bottom portion housed the "electronics", while the base was sand-loaded for stability.

If you refer to the pictures, you should be able to follow the project easily. The top is cut off near the 'node', while the bottom cavity is larger to accommodate the sand that gives a heavy and stable base.

Now follow the photo and mark the 45 degree cut and the verticals to the bottom cut--be careful to mark the verticals along the 'grain' of the bamboo. Do the slant and the straight cuts with a small hobby hacksaw--be very careful about the end points. Now use a small chisel, or a sharp knife and a small hammer and cut along the verticals carefully. The chisel/knife going in will be enough to split the bamboo along its grain, and if you are careful, in a matter of minutes you will end up with two neat pieces.



Do have a look at the photos. I am sure your ingenuity will find a use for that "waste" piece of bamboo in another project.

Now clean and rub the inside of the bamboo piece (which forms the body of the lamp) with some medium sandpaper and leave to dry in the shade for at least a day. Now drill the holes for the mains cord, a small toggle on/off switch in the back  just above the bottom node. Cut a disc of phenolic /acrylic for mounting the LEDs and see that it fits the top 45 degree cut. Here it is best to mark it on a piece of card and then use it as a template to cut the acrylic. (Also mark and drill the holes for mounting the LEDs.) Now give a couple of coats of wood polish to the bamboo, inside and out. Once the polish has dried, take some clean, dry beach/river sand and fill the bottom cavity with that. Pour a thin layer of wood glue like Fevicol to seal the sand and keep it inverted until dry. Now stick a thin layer of foam to serve as a non-skid foot.

Wire up the mains cord, the on/off switch , the dropper cap, bridge etc and connect two small wires to the + and - outputs. Stick these wires to the back support vertically so as to reach the LED housing.  Now wire up the LEDs. I still recommed that you go for pulsed DC operation (and not for pure DC) as we have been doing for all our projects, as this gives a higher brightness and also some "rest" for the LEDs during the off periods. Wire 3/4/5 LEDs in series with a small series resistor of about 150 Ohms to 100 Ohms, and use as many such " strings" as you need to cover the LED holder disc. Naturally the size of the disc depends on the diameter of the bamboo you have chosen and this needs some careful planning. Now connect up everything and test. Once everything tests okay, fix the LED disc onto the bamboo body with some hot-melt glue. Cut off one node of a smaller section of bamboo to serve as a " press-fit lid" for the bottom electronics housing. You are finished!

The more resourceful DIYer might want to use a small torch reflector or something like that from the junkbox to house the LEDs. A fellow DIYer tells me he is planning to use a reflector and a 1 Watt "high-power" LED that he has (from a broken torchlight). I am sure you could come up with your own variations, as the basic design is sufficiently "open", and so your ingenuity is the only ruling factor.

Once the project is finished, put it in a "custom-made" cardboard box, wrap it up nicely and make a present of it to whoever is "significant" in your life. I would guarantee that the LEDs are sure to be less bright than the face of the recipient!

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