Lord of the Lights

One Light to burn them all :-)
A little sunday afternoon project and my 2ct for a better world; old and "empty" cells can be reused down to 0,5V. This flashlight works with AAA, AA and coin cells. With a little change in the inside you can also put in a 9V battery.

Specs:

• 2x 3V white LEDs
• AAA or AA cells (2 cells possible)
• Coin cells (stackable)
• 9V block (the wall between "AAA" and "electronics" needs to be removed)
• works with 1 cell down to 0.5V to produce 3V

electronic parts:

• 2 LEDs: white; max 3V
• 2 Coils: 470 uH
• Resistor: 32k Ohm
• Transistor: f.e. BC548
• capacitor: 680 pF
• micro switch: f.e. US # MJTP1119 / EU # PHAP3351 (you can also update the design to put in any other kind of switch)
• spare piece of circuit board (max 6.8 x 1.3cm or 2.5x2.5cm if you want to use the space of the coin cell)
• optional: coin cell holder (fe. for CR2032 cells)

Please feel free to update the design, change the button part or put the electronics in the place of the coin cell to use 2 AAA cells.

cheers
chris