Our hackerspace the RabbitHole participated in a 48 hour competition for makers called the Deconstruction. The goal was to deconstruct the world around us and create something completely new from existing objects.

Our makerspace is very fortunate to have technical items donated. We often get broken laptops and computers which are salvaged for the working parts. There are a large number of power supplies and computer fans in storage bins that over flow. I set forth to make something useful from our abundance of equipment.

Making a larger fan of smaller computer fans was not an original idea, but making a fan in the shape of a skull was my idea. Everything is better with skulls!

Here are the things I used to create the skull fan:

Parts:

Computer fans (the skull fan used 25 of various sizes)
Sheet metal (scrap from duct work)
Machine screws and matching nuts
Plastic zip ties
Power supply (at least 12 volt)
Extra wire
Shrink wrap tubing or electrical tape

Tools:

Tin snips
Screw driver
Pliers
Nail or punch
Hammer
Drill
Soldering iron
Hot glue gun

Step 1: Layout Your Fans

We had many fans and some of them were of different sizes. Most of the fans were 80mm x 80mm, so rows fit together nicely. The skull fan ended up using 25 fans (and we still have more fans in the bin)!

Lay the fans out on a table and arranged them until they look like a skull. On this step make sure you have all the fans facing the same direction and rotate the fans so the wires come out near each other or are accessible later. Most computer fans will have an arrow indicating the airflow direction on the side of the fan. Make sure they all are pointing the same direction.

I had two fans with LEDs that were used for the "eyes" of the skull. Another clear fan (without LEDs) was used for the "nose". This helped make it look more like a skull rather than a boxy fan without character.

Step 2: Make the Brackets

To get the fans to keep the awesome skull shape they had to be attached to each other. I used metal brackets for the main shape and later added zip ties where the fan needed extra support.

To make the metal brackets:

Measure the distance between the holes of two adjacent fans. Mark the sheet metal with the distance. I found that a scrap metal grid that when turned diagonally was the correct distance. Take a nail or a punch and use hammer to make an indent in the metal where the hole should be. The indent helps the drill bit from wandering. Drill out the holes and use the tin snips to cut the sheet metal into small brackets.

This strategy worked well for the fans of the same size but there came a time to join up fans of different sizes. Those fans had holes different distances from the edge. I created a custom bracket for the odd sized fans.

To make a custom brackets:

Lay down the sheet metal on a soft surface such as scrap wood. Place the fans in the desired arrangement, it may helps to outline the fans on the metal as a guide. Insert a nail in the fan mounting holes and use the hammer to make the indent. Then drill out the indented parts and cut out the custom bracket. If you were careful, your holes line up and you can put the screws through the holes. If not, try again and make sure nothing moves when you make the indents!

Use zip ties:

In theory you could use zip ties to attach the fans. The skull shape necessitated some brackets. I put most of the brackets on one side and used zip ties to secure the other side where necessary for structure.

Step 3: Wire It Up

All the fans are wired in parallel (all the red wires to red, and black to black). I picked three areas to combine the wires: the top, right and left. All the red wires on the right side are combined together, all the black wires on the right side are combined together. I used hot glue and zip ties to keep some of the wires in place so they would not get stuck in a fan blade. Likewise for the top and left sides.

Some wires had to be lengthened to reach the combination points. I soldered extra wire so all red wires were combined on each section and all the black wires were combined. Test your solder connections and combined sections and fix as you go. After everything is working combine all sections until there is one group of red wires and one group of black wires.

Selecting a power supply was difficult. I sifted through the laptop power supplies trying several of them before finding one with a high enough current to run all the fans.

The fans were listed at 12 volts (V), but the power supply that worked happened to be 17 volts. The amperage (A) number is the important number. Since all the fans were wired in parallel I added up all the amperage values to see how many amps was required. I was unable to find a laptop power supply that was 10.35 amps, but I found that the 7.5 amp power supply was able to start a few fans slowly which lowers resistance and then all the other fans start running!

Cut off the end of the power supply and solder the positive (+) wire to red and the ground (GND) wire to black. Use a volt meter if you are not sure which end is positive (red) or ground (black). Be careful not to short out the power supply!

Step 4: Finishing Touches

Once the fan is assembled and wired it is time to add the finishing touches. I re-tightened the screws and nuts because several had come loose with construction.

Zip ties were added to the side opposite from the brackets to add structure and stability. The fans are arranged to where the skull fan can stand on its own weight when powered off. Once the fan starts the force is too much to stand on its own.

Use zip ties and hot glue to route the power cables so they would not get caught in the fans. There are lots of moving parts here so wire management is important.

Two larger zip ties were added at the top as handles to hold the fan upright when the mighty fan starts blowing!

Step 5: Enjoy Your Fan!

After all the steps are done you have fan in an awesome skull shape!

This particular fan was part of team Rabbit Hole's entry for the Deconstruction 2014. I was really surprised how much air the 25 fans moved (check out the 3 minute video here)!

You can do it! Please reply if you have done a project similar to this, or tell me what shapes you are working on!

Thanks for reading.