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Step 5Create the Light Circuit
The kindle 3 supplies roughly 4 volts through its clips. This can easily power several 3mm white leds for many hours. The circuit below will provide two different brightness settings. Try varying the resistor values to find a brightness level that you find pleasing. For average white 3mm white LEDs, a minimum resistance of around 40 ohms is needed to protect the LEDs from the full forward voltage.
I suggest laying out the circuit on a bread board and testing it before you solder anything.
Parts list:
* 1x SP Three Throw micro switch - RSOnline.co.uk part 718-2317 or similar (on-on-on type)
* 3x 3 mm white LEDs
* 3x R1: 220 ohm
* 3x R2: 1000 ohm P
* Stranded hookup wire
* 80 x 12 mm proto board
1) Solder all the components EXCEPT the LEDs to a piece of proto board 80 x 12 mm. I suggest adding the LEDs after you have created the light housing as they are difficult to align properly. Consider where the LEDs will connect when placing the resistors. Remember that the LEDs' positive lead will connect to both resistors.
2) Use hot glue to attach the LEDs to the brass LED plate. Take note of the NEGATIVE LED lead. If the leads are oriented consistently, it will make soldering them into the circuit board much easier. I oriented mine with the negative lead to the right when looking at the leads.
3) Orient the circuit board with the resistors facing down. This will make soldering the LED leads much easier. Tack the circuit board into the light base using a few small dabs of hot glue.
4) Orient the LED plate with the leds near the edge of the light base with the switch facing to the right and the resistors facing down. Bend the LED leads and guide them into the proper locations in your circuit board.
5) Use a small blob of hot glue to tack down the light plate while you solder the LEDs into place.
6) Test your circuit! Connect the negative side of your circuit to the black clip and the positive side to the red clip. The LEDs should all light up. If not, check your solder joints and resistor placement.
7) Connect the 718-2317 switch. The 718-2317 switch slider connects the two poles directly under it. Connect the dim and bright segments of the circuit to poles [1] and [3] as shown in the last image. The middle pole [2] will be +4V from the Kindle. Pole [4] is unused. This will provide off, dim and bright settings.
I suggest laying out the circuit on a bread board and testing it before you solder anything.
Parts list:
* 1x SP Three Throw micro switch - RSOnline.co.uk part 718-2317 or similar (on-on-on type)
* 3x 3 mm white LEDs
* 3x R1: 220 ohm
* 3x R2: 1000 ohm P
* Stranded hookup wire
* 80 x 12 mm proto board
1) Solder all the components EXCEPT the LEDs to a piece of proto board 80 x 12 mm. I suggest adding the LEDs after you have created the light housing as they are difficult to align properly. Consider where the LEDs will connect when placing the resistors. Remember that the LEDs' positive lead will connect to both resistors.
2) Use hot glue to attach the LEDs to the brass LED plate. Take note of the NEGATIVE LED lead. If the leads are oriented consistently, it will make soldering them into the circuit board much easier. I oriented mine with the negative lead to the right when looking at the leads.
3) Orient the circuit board with the resistors facing down. This will make soldering the LED leads much easier. Tack the circuit board into the light base using a few small dabs of hot glue.
4) Orient the LED plate with the leds near the edge of the light base with the switch facing to the right and the resistors facing down. Bend the LED leads and guide them into the proper locations in your circuit board.
5) Use a small blob of hot glue to tack down the light plate while you solder the LEDs into place.
6) Test your circuit! Connect the negative side of your circuit to the black clip and the positive side to the red clip. The LEDs should all light up. If not, check your solder joints and resistor placement.
7) Connect the 718-2317 switch. The 718-2317 switch slider connects the two poles directly under it. Connect the dim and bright segments of the circuit to poles [1] and [3] as shown in the last image. The middle pole [2] will be +4V from the Kindle. Pole [4] is unused. This will provide off, dim and bright settings.
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