The Wallet Prototype Revisited

In this post I’ll follow up a post from over a year ago in which I discussed a wallet prototype that I designed and fabricated. To recap, I never had a wallet that I felt was well designed for me so I decided to design one of my own. I had a couple of key criteria including that it was super thin, protected my business cards, and allowed my to get my cash and license out of my pocket without having to take the entire wallet out. My first prototype was fabricated out of duct tape and worked quite well. It survived a surprisingly long time as well, till about a month ago.

Granted, it had some issues that prevented me from fabricating another one out of duct tape, but it was clearly good enough to keep me from making something better until it literally fell apart. It’s amazing how durable duct tape is! One downside of the material is the fact that it can get a little sticky at the edges where the adhesive is exposed. It also tends to stretch out over time which wasn’t ideal. Ok, so on to the next generation!

Before fabricating something usable, I decided to make some prototypes out of paper to determine the best possible fabrication pattern. Now that I was going to use a sheet material (rather than strips) the parts would be quite different. I can up with four potential fabrication plans which put the seams in different places … and one that was made from a tube of fabric. Some required glued, or bonded, seams others did not. Ultimately, I settled on a minimal design that requires only six straight-line sewn edges, or six heat-bonded seams depending on the fabrication material.

The final design uses lass material, requires three pieces of material and includes several other improvements. These include:

  1. better business card protection due to a slightly deeper pocket.
  2. reduced lint/dirt contamination due to openings at the bottom of the pockets.
  3. slimmer, due to less material used.
  4. better edge protection for bills due to outside seam placement.
  5. easier card access due to shortening of the inside pockets, fabric with less friction, and the removal of triangular cut outs.
  6. more durable, due to synthetic fabric.


Now that I’ve got a super solid design that I’m happy with, I’m looking forward to moving away from the white material (which was helpful far marking) and fabricating samples in higher fidelity with the use of a heat cutter and sewing machine. For those interested in seeing some of the process I went through to get to this design, I’m including images of some of the earlier prototypes below.

Earlier Prototypes









A Prototyping Conundrum

A good friend and I are working on an invention that we believe will solve a problem faced by urban bikers. I can’t say much more than that, but that’s probably all you really need to know in order to consider my prototyping conundrum. It deals with a common problem, I believe, that arises when prototyping to test your concept versus prototyping for manufacture.

When should we be thinking in terms of the final (manufactured) design and when should we be thinking in terms of the design that is required to test and get feedback on the concept? You see, we’re planning on doing a short run of the device (say 100 units) so we can do some testing and it doesn’t make sense to have them cast. Following this, we have to change some elements of the design to accommodate manufacture by other means.

Should we have two separate prototype paths?
In reality, the details aren’t THAT different but it can be confusing because we haven’t been good as saying “with respect to the testing prototype, I think we should …” My gut tells me that we just need to add some structure to our process to resolve this issue for now. But, you do have to wonder how to balance your time and effort between the two prototypes.

Is it a marketing issue?
Some of the details in question are purely aesthetic or at least partially aesthetic and it’s unclear how much weight to give them. Though clearly, that’s more of an issue with the manufacturing prototype. There’s also the issue of cost of goods sold and how our choices will effect that. Our designs have evolved quite a bit so we haven’t had the chance to speak with potential manufactures about the impact of our choices. My partner is an engineer, but still we don’t really have a sense of if we’re talking about dollars per unit or cents for some of our choices.

When should we think about cost? For me, and with regard to this device,  it boils down to the fact that no matter what we do our device will cost significantly less than other devices in the same category …. so I’m not really worried about cost too much at this point. Maybe that’s wrong, but it seems to me that we should come up with the “best” solution and try to control costs from there. I guess this stems from my belief that people are willing to pay for great products and that pricing is in large part irrational (refer to Predictably Irrational if you want more on why).

I welcome your thoughts!

Putting Your Design Where Your Money Is: A Prototype Wallet

For the past several years, I’ve been walking around with a wallet that is actually the insert for a larger one. At first this was because wallets just seemed bigger than they should be, But over the years I realized that I’ve never found a wallet that really anticipates my behaviors well. For example, being able to reach into my pocket to get my driver’s license or cash without having to pull out the entire wallet. I’ve also never had a wallet in which I can hold business cards without mashing their edges. There are other issues, but those seem to rise to the top.

In true Adaptive Path fashion, I decided it was time to do some rapid prototyping. I started with paper prototypes which I unfolded and used to create a fabrication drawing. I then sent it off to a leather guy to make a better prototype. Regrettably, the fabricator did not fully understand the project, despite lots of notation on the fabrication spec, and I got back something that was worse than my paper version. The dimensions were off and it was made from thick leather that made the wallet too big and stiff. The lesson I took away from this is that you should always try and make the prototype yourself if possible because you understand your goals better than you can possibly explain in a spec. So, I decided that I’d look into making a prototype that was better than paper, but which didn’t require special tools. That’s when the duct tape came in. I’d seen duct tape wallets before so I decided to try making one myself.

I liked the basic design of the insert wallet I had, but it needed some adjustments. Below you can see images of my old wallet next to the prototype I created. I’ve only been using it for one day but I already know I’m heading in the right direction. I’ve turned up a couple issues that will impact my next prototype as well. Yay for prototypes! Let me know what you think!

Old Wallet Inside View – As you can see the cash is simply folded in the middle which allows you to peel off bills like a bill fold. I used to use a bobby pin to keep the cash in, but ultimately found that it was unnecessary. Also, I liked being able to take the cash out of my pocket without the wallet (this requires that you put the wallet in your pocket with the open end up).



Prototype Wallet Inside View – As you can see it’s very similar, though instead of using clear plastic that tears easily, I opted for triangular thumb pulls which make getting the cards out easier.



Old Wallet Inside View Without Cash – here’s what it looks like without cash in it (I hate it when that happens)



Prototype Wallet Inside View Without Cash – same.




Old Wallet Outside View – you can see here that the driver’s license is held on the outside, which I really liked. This way you can quickly reach into your pocket and pull out just the license.


Prototype Wallet Outside View – I kept the license on the outside, but added a pocket on the other side for business cards rather than keeping them on the inside like in the old wallet. This allowed me to create a flap of material over the entire business card that keeps the edges clean (note that the pocket in which the license sits leaves the edge of the license exposed). My next version will add a thin plastic card over the business cards to protect them even more.



Old Wallet Side View – The old one was pretty thin, which I really liked.



New Wallet Side View – the new one is slightly thinner because of the material used. Ultimately, I might have this fabricated from a thin, durable, and slightly stretchy cardura.




Here are some other interesting thin wallets:

Wallet Pens