A DIY LED Spotlight

Take a screwdriver to the halogen bulb and twist away at the white cement that sits around the bulb's pins. Gently chip away at the fine cement until most of it crumbles away.

Place the bulb, pin legs protruding upwards, on a flat surface and proceed to firmly hit the legs with a hammer until the bulb falls out leaving an empty reflector.

Cut out a 1 1/2-inch diameter disc from the aluminum sheet and using the hole-punch to make the required number of 1/5-inch holes for each LED (22 in this example). The disk will also act as a light reflector.

Set up the holed disk in a holding device that will allow you to place the LEDs into the holes, legs up, and secure with a drop of superglue. To make soldering easier arrange the LEDs so that a cathode (negative leg) sits next to an anode (positive leg). Add compound glue to reinforce the hold.

Calculate how you will connect the LEDs into parallel strings in series with resistors. For 22 LEDs you can arrange 5 strings of 4 LEDs with 1 ohm of resistance and 1 string of 2 LEDs with 330 ohms of resistance. This makes sure that the right amount of current and voltage reaches every LED.

Trim the LED legs with nailclippers, keeping the anode legs slightly longer than the cathode legs for the purposes of identification. Then solder an anode to the adjacent cathode until you have a string of four and proceed until all the strings are connected.

Solder the six slightly longer anode legs to one another, ensuring there is a safe distance over the other connections to minimize chances of a short circuit. Vertically solder the resistors to the remaining cathode legs.

Solder the resistors together, taking into consideration that the structure will need to fit into the bulb.

Then solder thicker copper wire to remaining final two parallel legs, remembering to keep the negative wire shorter.

Place the bulb back into the reflector and push down until the aluminum disk comes to rest on its inner side. Apply a liberal amount of compound glue to holes at the back of the bulb where the two wires exit and wait for it to harden.

Mark the positive and negative terminals with a pen, and also mark the voltage the bulb will use (12V).

Cut the legs to equal length and attach to a 12V battery.