How to make one flashlight from an old 9V battery.
1 old 9V battery
1 super bright white LED
1 resistor 330R
1 little switch
Step 1: Disassemble the Battery
The first step is to disassemble the battery, using a knife to open the bottom of the case, as shown in the picture.
After that, remove the inner parts of the battery, keeping only the little strip connected to the negative pole and the case.
Step 2: Solder the Parts
In this step solder all the components to each other, like shows the picture, making a series, starting from the positive pole, soldering 1 pin of the switch directly to the positive pole and the other pin to the resistor, which will be connected to the LED.
The negative pole is directly connected to the Cathode of the LED with the strip of the battery that was kept in the step before.
Step 3: Fill With Plasticine
With all the parts connected and after the confirmation that the circuit lights the LED on, connecting it to another (good) 9V battery, it's time to fill the empty space of the flashlight with plasticine (or sugru), like shows the picture, to stow the components inside the case.
The case, that was kept from the old battery, need to have one rip, in order to fit the cap of the switch, in the assembling process.
Step 4: Put the Case On
To finish, put the case on, using a pliers to round the bottom, closing it.
And that's it - IT's DONE!
Step 5: Testing
Now we have one little shiny flashlight, to use wherever it's useful.