Welcome everybody. This instructable is on making DIY Laptop cooling System from easily available materials and scraps. Although laptop cooling systems are not very costly or hard to find. But making you own has a different fun in it. I have seen many people making different types of cooling system. I will explain the one that I have made in this instructable.

Step 1: Collecting the Materials

Here is the list of all the items:

A cardboard box. I used a photo frame packing box. Its a bit hard and the size is perfect.
2 x CPU cooling fan of size 90 mm x 90 mm. (You can use any size of your choice. Make sure the fan covers the ventilation under the processor.)
1 x CPU cooling fan of size 40 mm x 40 mm. (Well this fan is optional. It is to take out the hot air from the cooling system. If you don't want to use this fan then just put some ventilation in the cardboard.)
Vero board.
6 pin Relimate connector. (I could not find a 6-pin relimate connector. So I used one 4-pin and one 2-pin connector).
Self locking switch.
3 mm Red LED and a 1K resistor. (Optional)
1000uF / 16V electrolytic capacitor.
Step down transformer.
2-pin mains (AC) chord.
Heat shrink tubes of different sizes.
2 x 1N4007 diode.
Some wires for making connections.

If you are using transformer greater than 15 V in the LV side then you will need some additional items:

LM7812T
100uF / 16V electrolytic capacitor
100uF/ 25V electrolytic capacitor
Aluminium heat sink for LM7812T.

Equipments that would be required:

soldering station
sharp knife or cutter
Marker
Geometrical Compass with pencil
Ruler
Glue
Screw Driver
Some M3 screws with nuts and washers.
Drilling machine (if you have one).

Step 2: Soldering the Components in the Vero Board

There are two schematics shown. If you are using transformer of Secondary voltage 18V or more then use the schematic having LM7812T. Don't use transformer of secondary voltage higher than 40V. It can damage the voltage regulator.

Some cooling fan readily comes with the relimate connectors. But some don't. In that case you have to join the relimate connectors to the fan.

Step 3: Cutting the Cardboard and Place the Components

Place your laptop on the top of the cardboard and roughly make an idea where are the ventilators of processor located below the laptop.
Measure the diameter of the fan and find the radius. On the top of the cardboard, using the Geometric compass draw a circle with radius equal to the radius of the fan roughly below the ventilators. Cut out the piece of cardboard to make the circular hole using a sharp knife or cutter.
For the 40mm x 40mm fan, draw a circle equal to the radius of the 40mm x 40mm fan on one of the sides and cut out the hole. If you don't want to use this fan just cut some ventilators on the sides of the cardboard for the hot air to come out.
Drill a hole on any one side to place the switch. You may also use your cutter to make the cutting. Drill another hole on the back facing side to pass the AC mains cable. On the front facing side make a small hole to place the LED.
Mark the points where screw holes are located on the fans and transformer. Drill holes with proper drill bit. Use small dia drill bits. Drill two holes on the Vero board diagonally opposite to one another.
Now place all the components inside the cardboard box. While placing the fans on the top side, make sure that air is sucked from the top when the laptop is placed above the cardboard box. Hot air from inside the laptop should be sucked.

Step 4: Making the Connections

In the secondary coil of the center tapped transformer there will the three wires. The one in the middle is the ground. Solder this to the ground of the LM7812. Connect the other 2 wires are to the anode of the diodes. Short the cathode of the two diodes and connect it to the INPUT (Pin 1) of LM7812. Rest of the connections are shown in the schematic in step 2 of this instructable.

Now connect one of the wires coming out of the primary coil of transformer to switch and other wire to the AC mains cable black wire. Take a wire and connect the other end of switch to the AC mains cable red wire. Cover all the connections using Heat shrink tubes or electrical tape.

Step 5: Ready to Use

Now everything is complete. You may cover the cardboard with colored tape to make it look better.

I have not explained all the steps in very details. Please feel free to ask any question if you have problem in making this project. This instructable is very easy. Simple by looking into the images one can make their own. No special knowledge in electronics is required to make this except a bit soldering skill. The cool thing about this is that you can use lot of scrap items like the cardboard box, old CPU cooling fan (if you have one), transformer from old electronics devices like DVD player. I only had to buy the 2 fans and the rest of the components are taken from scraps. Even the capacitors, resistors and LED is also collected from scrap items.

Try this and post photos in the comment. I would love to see them.

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