Howdy everyone. This tutorial covers the steps required to recreate my final year project, an inflatable, external hard-drive. This is an attempt to reintroduce physical consequence to intangible digital data, and in doing so utilise our evolved ability to make value judgements within the analogue world.

This is a prototype design. As such improvisation will be necessary when recreating/improving on what I've done here. The nature of 3D files, varying printers, and my inexperience will mean that certain parts require sanding for an airtight fit which is paramount for a functioning device.

Step 1: Parts Required

3D printed parts

Powered components

MOSFET breakout board x 2
Arduino
Hard drive
Hard drive USB case
12V DC pump x 2
12V DC input
12V power supply/plug
USB Hub (taken from RCA splitter)
Serial cable + Hard drive cable
Electrical cable

Mechanical components

Pneumatic tubing
Check valves x 2
2mm Latex sheet
Rubber bands

Construction components

Epoxy glue
Plastic weld
Standoff set
Shrink tubes
Hose clamp

Code

Arduino + Javascript code

Step 2: Installing Hub Splitter, Arduino + Mosfets

I had great difficulty finding a USB hub breakout board, so I've taken the internals from the RCA splitter and used this in the final model. Adjustments can be made to the original CAD file to facilitate alternatives.

This is a fiddly process but it must be done prior to installing the HD housing on the top half of the model as the screws used in the standoff assembly will be unreachable after installation.

Step 3: 12V DC Input + HD Housing Installation

Solder electrical wire to the 12V jack as it will be inaccessible after the top and bottom half have been glued together.

Glue the HD housing to the top half with plastic weld. The USB cable from the hub will be clamped between the top and bottom half during glue up. Leave enough wire to allow for the HD itself to be installed into the housing otherwise the USB cable will make it inaccessible

Step 4: Top and Bottom Glue Up + Component Housings

Not a particularly simple operation. I recommend placing some pneumatic tubing into the through holes to line up the two halves perfectly. They should be easily removable after the glue is set. An air tight seal between the halves is paramount, however plastic weld can be added in post.

Install the plug that seals the 12V DC jack and add glue around the electrical wire to ensure a seal

Use plastic weld to install component housings as per the image. Location should be evident in layout of top half.

Step 5: Wiring

Add shrink wrap tubing to soldered connections to prevent short circuits

Step 6: Check Valve + Pneumatic Tubing Install

Make sure pneumatic tubing is pushed as far as it will go into each check valve before cutting to size.

The check valves do not need to be perfectly seated in the housing to function. The housing that they sit in may even be superfluous.

Step 7: Latex Wrap

Prior to the latex wrap run the cables from the arduino and HD to the hub, and upload the arduino code. Power up the drive and run the code, placing files onto and off of the drive, making sure that the pumps inflate and deflate in relation to the data uploaded.

Remember to click + shift a file onto the drive to prevent copying the file and doubling up pump time. A quirk of data transfer!

Place the latex over the body of the IHD, and then the hose clamp over this. Pull the latex taught as you tighten the hose clamp to produce as seamless a seal between the clamp and the rubber bands underneath.

You will have to add further measures to ensure the drive is airtight.

Step 8: Trim and Test

Trimming the latex is fairly self explanatory. I found that the hose clamp was unable to create an air tight seal so I added extensive amounts of hot glue, however I think grouting sealant would provide a better seal and be more aesthetically pleasing.

Step 9: Improvements

I'd like to redesign the body so that it creates an air tight seal between itself and the latex without the need for glue using a mechanism shown in Fig. 1.

Also, the arduino and hub could be replaced with a raspberry pi or custom pcb.