Intro: Precision LED Task Light
Sometimes you need a little more light in just the right place, perhaps not a lot of light but precisely where you need it - one solution is this precision LED task light. I built my first because despite a nice light on my band saw the machine cast a shadow on just the place I wanted to see: where the saw blade went into the wood. This is a pretty simple build using a single LED. Here is how to build the light.
Step 1: Tools and Materials
- A superbright white LED– these are under a dime at many sites on the web, I think I got a pack of 25 a year or so ago.
- A switch ( optional I did not use this )
- A power supply, there are options here too, I used a 5 volt wall wart left over from a discarded phone
- Fairly heavy copper wire, single strand, mine came from left over house wiring ( romex )
- A power cord, I salvaged mine from an old mouse cable, you can just use the cord on the wall wart if you are using one.
- Current limiting resistor about 200 ohms, you need to do a calculation depending on your power supply
- Electrical tape and or heat shrink tubing
- Soldering Iron
Step 2: Calculate the Series Resistor
The value of the series resistor should limit the current to 10 to 20 ma, or if you have the spec sheet for your LED refer to it. There are many ways to figure this out, one just use a 200 ohm resistor it may work, or look at: https://www.instructables.com/id/Ultimate-guide-to-LEDs/step9/LED-resistors/
Step 3: Wire It Up
The power supply, LED, and resistor all go in series, mount the LED at the end of the wire. I like to mount the resistor right next to the LED. Eliminate shorts using heat shrink tubing and /or electrical tape. The pictures should make it pretty clear. A section of the heavy copper wire goes into the assembly to mount the LED, this is seperate from the power wire. You can bend the wire to get the lamp into the exact position you want it.
While I used a wall wart for power you may want to use batteries, 3 double AA's will do, a nice case for these is at: Battery Holder for Double A, Triple A, C and D cells-batteries. Cheap, Good, Easy . If you want a switch add it, in series, at a convenient point. I did not.
The last 2 pictures here shown here include some work done in the next step.
Step 4: Mount It
The light is mounted on the stiff piece of copper wire ( I leave the insulation on ). Slip some heat shrink tube over the LED, and push the wire in alongside it. Shrink it, and add some tape just to be sure. Some of this can be seen in the prior step.
The task light can be fastened in place by wraping it around 2 screws or bolts near where you want the light. The wire is then adjusted to light the task. I decided to use a magnetic base: its construction can be found at: Magnetic Lamp and Tool Holder - Using Microwave Salvage Step 6.
Step 5: Use It
Now I can see much better. In the future I may wire it into the circuit that runs the bandsaw motor, that will take care of turning it on and off for me.