Introduction: In-Keyboard Desk Backlight
Hello members, and thanks for checking out my first step by step instructable.
So I was looking around at all of the keyboard modifications and figured I would show how to easily create a back-light for your desk by modifying your keyboard.
It is nothing too complicated, it is just a simple mod where I integrated some LEDs into the keyboard to light up my desk for some cool aesthetics.
Step 1: Supplies and Tools
- LEDs of any color
- 22 gauge wire
- small switch
Supplies I used:
- 6 Ultraviolet LEDs (3.3 forward voltage, 20 mA each)
- 6 100 ohm resistors (one for each LED)
- 22 gauge wire
- standard HP keyboard
- 1.5 Amp mini toggle switch
25w Soldering iron
Small solder (.022mm)
Power drill with 7/32 drill bit (not pictured)
Hot glue gun
Wire shrink wrap (although I never used mine to save space)
Step 2: Take Apart Keyboard
Take the screws out of the keyboard and take off the cover holding the keys.
There should be a rubber cover over the electronic plastic sheeting, remove this next, it should come right off.
Next, unplug the circuit board in the top right corner and unscrew the panel holding it down. Once removed, carefully remove the plastic sheeting for the keys and place it with the rubber cover.
Then take out the power cord so it doesn't get in your way.
Step 3: Creating and Testing the Circuit
To find out how to wire your LED circuit in terms of what resistors to use you need to take a voltage reading of the cable.
Note the red and black cables in the power cord, these are the power and ground cables, the only two you will need to mess with.
While the cable is plugged into the computer, take a voltage reading, mine was 5v. Not sure if this is standard but I'm guessing it is for most keyboards that simply run off computer power.
So with 5v as a power source, and given that each LED has a forward voltage of 3.3v while using 20mA, then a resistor of about 100ohm should be just right.
It isn't entirely necessary to use one resistor per LED but I did just in case although thinking back it is definitely overkill. You could always use one resistor for the whole circuit considering the LEDs are wired in parallel, to make it easier on yourself.
After you find the correct resistor, create the circuit on a breadboard first and then get some wire and power it by putting the wires into the receptacle of the black and red wires of the keyboard cable while it is plugged into the computer. Just make sure your circuit works with the supplied voltage basically...
Step 4: Drill Holes and Lay the Circuit Out
Now figure out how you want to space the LEDs in the keyboard.
I placed 4 in a row and then two up top. My HP keyboard luckily has an indented back so that when the LEDs come out of the bottom they are still not touching the desk, therefore no pressure will be put on them while typing.
Once you have figured out where to place them, drill the holes for them to go through. I had 5mm LEDs so I used a 7/32 drill bit and it worked perfectly.
Next, cut wires of appropriate length and lay the circuit out within the keyboard to get a general idea of where everything is going to go.
Step 5: Start Soldering
Now start by soldering the resistors to the LEDs after trimming down the legs on the LEDs.
Then connect all LEDs in parallel and feed the wires back towards where the power cable enters the keyboard.
Keep in mind that all wires and LEDs must stay below the plastic "maze" of where each key on the keyboard is so that the electronic plastic sheeting you took out in the beginning can still lay flat in the keyboard.
Step 6: Connect the Power Cable, and Glue Everything in Place
Next cut the red and black wires for the power cable, somewhere in the middle, and soldering them to the corresponding ground and power wire for the switch.
The power wires for the rest of the circuit should obviously be connected to the other side of the switch.
Then once this is complete, super glue the LEDs into place and some of the loose wiring. Once it is secure, cover the exposed metal solder points and other metal areas with the hot glue gun so that none of the points short circuit the keyboard if they come into contact with the circuit board or electronic plastic sheeting.
Once again make sure that when you are gluing the circuit with the hot glue gun that the globs of glue sit below the plastic frame for the keys so that the plastic sheet may still sit flat.
Step 7: Sit Back and Appreciate the New Glow
Put the sheeting back in with the rubber on top, then screw back in the circuit board and reattach the power cable, screw the keyboard back together and you are done.
Now you can sit back and appreciate the new glow.
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