Introduction: Combination Lock USB Memory Stick

Picture of Combination Lock USB Memory Stick

The Problem:
I have a USB memory stick with built in security software, GREAT! However it tends to be a little unreliable when it comes to using the memory stick on computers other than my own either taking ages to get logged into it or even not getting access to it at all.

The Solution:
So i decided that after receiving a free 3D print from the last competition i decided i would design a combination locked USB memory stick using Solidworks 3D!! Which should be here any day?

Using 4 wheels numbered 0 - 9 gives me 10,000 Combinations!!!!!!

Here are the results and i hope you enjoy the step by step guide

****now available to buy at shapeways link below****

Step 1: USB Memory

Picture of USB Memory

The first step was to draw up the USB memory i had purchased for the project, it was relatively small 1Gb but it was all i could find at the time and it is specifically sold without a case for the purpose of making a case/container yourself, alternatively if your needing a larger memory capacity jusy remove the business end from one you previously purchased.

I started off by measuring the usb with a set of calipers and making a sketch of the PCB on the top plane and extruding it to the appropriate depth.

Next on the right plane i sketched the metal part of the USB (male End) extruding it also.

With the USB completed in one part i could now use it to design my casing around!!

Step 2: USB Circuit Board (PCB) Casing.

Picture of USB Circuit Board (PCB) Casing.

After examining a few USB cables lying aroung i settled on a measurement for the amount i want the metal end protruding from the casing and using this measurement along with the overall length of the PCB and a couple of millimetres for the casing thickness i was able to sketch and extrude a suitable casing length.

The catches/location points for the combination wheels were refined in the assembly at a later point!!

Step 3: Recieving End of the Casing Combination Wheels

Picture of Recieving End of the Casing Combination Wheels

The Recieving casing was a little more difficult and thought provoking to sketch and extrude never the less a suitable result was achieved.

With this completed i could draw the edn cap for it which would keep the combination wheels on and in place.

The next part to draw was the combination wheel.

Step 4: The Finished Product!!!

Picture of The Finished Product!!!

And so the completed USB casing should look a little something like this !!!


jamesharper11 (author)2014-09-24

it needs measurements

eblackman1 (author)2013-09-09

That is ace!!

qwerty924 (author)2012-12-20

i love this idea and I've started making my own in auto-desk inventor BUT it would be helpful if you had included the dimensions for the pieces and maybe a little bit more detail on how to make each individual piece because i'm having a bit of trouble with the combination rings...other than that this instructable is definitely in the top ten for me

tycj (author)2012-12-03

I only use a manual lathes too but they are too bog to machine out the parts for this, a modelling lathe and a milling machine would be proper job.... Have you any photos of it van.

vanwazltoff (author)2012-12-03

i made one out of aluminum in my machining class, had extra time and i used a standard usb 3.0 flash dive. to be clear i did not use a CNC, im just that good on a manual lathe and knee mill =P

vanwazltoff (author)vanwazltoff2012-12-03

i actually made it dual purpose, if i had the chain it could also be a bike lock

A P3RS0N (author)2012-10-22

The main problem I see with this is that it's made of plastic. It doesn't take a lot to break plastic. Perhaps some sort of strong metal (Steel, Titanium, etc.) and/or spikes attached to the case that the flash drive rests on in order to smash the chip if it's broken into might be a useful addition.

Also, the issue of cracking it with tension is important as well. Some way to lock the discs when tension is applied would do quite well.

However, this is certainly a novel concept. If it were a bit more secure (and reasonably-priced), I know of people who would buy it.

jim_lewis1 (author)2012-10-19

Nice. As others have mentioned the removable part could potentially be too 'deep' to sit well when inserted into a laptop, but in fact this part doesn't need to be a complete cylinder anyway.

If you flattened the underside leaving just the top two thirds or so of the cylinder it would still lock into the combination part, but would no longer have this issue.

lynx66 (author)jim_lewis12012-10-20

good idea

l33tg4merz (author)2012-10-16

Who need security software when you have this? :) Very nicely done.

soshimo (author)l33tg4merz2012-10-18

Not really. With 10k combinations, and assuming each try takes 10 seconds (fast fingers) you could have it open in less than 27 hours using brute force. It just keeps the honest people honest ;)

But I agree, well done, but let's see it when it's printed. ;)

lynx66 (author)soshimo2012-10-20

also when its printed, the finished product will be plastic. so if they wanted it that badly they could just break it

tycj (author)2012-10-19

Yeah just reduce the male part jim.

lorenojr (author)2012-10-18

I'd made onde nor in 3D printer ,but is a lot of piece of PVC tube, in another Intructables (I can't remenber).But It's work well

tycj (author)2012-10-18

Nice idea Robbie... Yeah Jakob in waiting on the 3d printer to churn it out... hope its here soon.

Jakob2803 (author)2012-10-18

So did you actually make this or just draw it? :)

robbied (author)2012-10-18

A very creative way to make something like that secure. Also in that casing, it's more difficult to lose :)

robbied (author)robbied2012-10-18

and for those that like the brute force tension method, you could add slight notches, or 'false gates' to keep them guessing

Sarah86 (author)2012-10-18

I can actually see one big problem right away. How in the world are you actually going to put the ring on the shaft. If the combination ring are actually a complete different piece and the shaft have border on each end that are actually bigger thant the inner diameter of the ring, you will never be able to put them in place.

Ussually in a combination lock, the border facing the other part is put in place with fastener (bold, solder, or the ring is actually a nut with a looking bar).

St Jimmy (author)Sarah862012-10-18

What he's done to work around this problem is to have a smooth cylinder for the rings, then have a cap that holds them in place. If you look carefully at the first picture in Step 3 you can see it.

tycj (author)2012-10-18

That's an end cap which just slides on n stick it on with glue if necessary just for prototype was thinking about a simple threaded finish for the finished piece.

tjesse (author)2012-10-18

If you patent this and sell it, I will buy it.

chrwei (author)2012-10-18

another option is to make it slightly larger and just slide a usb stick into the cavity. the stick could them be removed and used in a laptop or in some other space constrained area. would allow easy upgrade of the stick too

tycj (author)2012-10-18

I like that idea vov !

vov35 (author)2012-10-18

Add some false gates to the combination disks! otherwise, this will be much too easy to manipulate open. manipulation procedure: apply tension, rotate each disk until it sticks, eventually (30seconds?) lock pops open.

No evidence of being tampered with, too.

tycj (author)2012-10-18

Good point James about laptop problem I was looking at a more flater case as you suggested but with slight change to the mechanism.

JamesRPatrick (author)2012-10-18

Interesting idea. Only potential issue I see is that the lock would hit the table if inserted into a laptop. If it is manufactured from metal, you could reduce the diameter and still retain strength. Another way to make it a little bit smaller is to use one of those flat USB sticks without metal sockets.


CescoAiel (author)2012-10-18

Nice idea!

If it works well enough, you could also put it in to a shop on a 3D printing site (like shapeways) and make some money off of it that way! ;)

tycj (author)2012-10-16

Thanks tom. They are just seperate rings with an end cap to hold them on so it will be possible to change the combinations. Probably just use some clear plastic tubing n slide it on to each ring with a little strip with 0 - 9 printed inside it.

Tomdf (author)2012-10-16

Great idea, like uncle marty said, marketable. I can totally see these for sale somewhere.

How do the encoder rings go on? will they be printed together, or will it be assembled later on somehow? It would be sweet to have a way to change the combination.

tycj (author)2012-10-16

Thanks marty I was thinking about it. Will get my hands on the prototype n sort out any problems then see about production.

uncle marty (author)2012-10-16

Great idea. This is probably a marketable device. You should protect it and contact a manufacturer. There are actually 9999 lock combinations as 1 is the open setting it looks like. Again great idea, market it and get rich or some hobby money anyways.

bethekind (author)2012-10-15

If you could add the 3d Solid Works program file, or export it to something and put it on this instructables page, it would make it way easier for everyone else to make it.

tycj (author)2012-10-15

Yeah I will do as soon as I get it. Just want to make sure it all goes together properly !

amandaghassaei (author)2012-10-15

this is so cool! I can't wait to see the final product, will you post your stl files?

tycj (author)2012-10-15

Hey thanks lyron

Lyron (author)2012-10-13

Cool project! I hope it'll work!

About This Instructable




More by tycj:Balsamic Marinade Floating Outrigging For a DroneDigging Buckets/Attatchments
Add instructable to: