This is the tale of an amazingly effective, slender, nearly invisible and inexpensive smartphone case. By posting this I'm making the idea open source, so hi. Dig it, improve it, sell a better version - if you do, I'll probably buy it.

SPOILER: The solution lies, not in padding, but in increasing the finger-traction of a phone where we grip it, the edges.

EXPOSITION: I'm still on iPhone 5 now. I got by pretty well with my iPhone4, only dropped it twice over three years and except for killing its WiFi, it was OK with no cracked screen. After the second drop (slow learner) I got a case for it. There are a lot of cases out there.

I use a belt-mounted "holster" for the phone, and when I stepped to the iPhone 5 I had to find a new holster. And then, after a couple of near-slips, I went looking for a phone case. Unfortunately, there wasn't much available that would fit into the nice snapless (magnets) leather holster I had by then. Which is when I started thinking.

There are actually two principal reasons that we get cases for our smartphones: to protect them from damage when they're dropped, and to keep from dropping them. Right? But this raises the question: if we can keep from dropping the thing in the first place, why worry about protection from a drop?

In other words, the priorities are reversed. The first goal is not to protect the phone, it's to find a way to keep it from being dropped. If we achieve that, we can abandon all the stuffing, padding, covers and shields that try to protect it from damage once it's plummeted to the floor and bounced from our sword and knife collection into the food processor.

I'll save you from the long journey of discovery. There is a nice, tractiony, finger-friendly material made by 3M that is intended for footsteps, walking paths and such. It's peel-off adhesive on one side, comes in spools from 3M but is often sold by the foot in hardware stores. I cut one foot of this inch-wide stuff off a reel, and bought it, ten cellphones' worth, for a buck.

With a ruler and X-Acto (TM, I guess), I cut a ribbon the length of the iPhone's perimeter and half it's width (NOTE: that is its not it's, but I throw that error in as a gift for the pedant within all of us), and then carefully cut that narrow ribbon into shorter lengths to dodge the volume buttons, connector, speakers, etc. Then I stuck them on. The phone still fit easily into the holster because its width was barely affected - indeed, the phone was even easier to put in and out because the new traction helped the grip but didn't stick to the case.


Darn, that worked great! So great that I cut an additional couple of 1cm-wide lengths to stretch down the the backside, which now kept it from slipping off my leg when I set it there.

More details follow, but that's the gist of it.

Here are a few additional actions and observations:

> The straight ribbon segments, with the original 3M adhesive, are still in place and secure after 9 months.

> The 3M stuff is "3M Consumer Safety-Walk Medium Duty Resilient Tread", part number is 7734, UPC 51131-59509. It comes in grey and black and various widths.

> After a few weeks, while the staight sections were still fine, the segments that rounded the corners of the phone started to peel up.

> To re-attach, I kept the original ribbons, removed the original adhesive with "Glu-Gone," and applied a light film of two-part epoxy in its place. Those have remained secure and in place. Note that Glu-Gone was not fully effective, some stickiness remained, but I guess it removed enough of the adhesive, if not all.

> A bit later, another corner piece started to peel and I reattached that using epoxy experimenting by doing this without the Glu-Gone pre-treatment. This did not set well, and peeled off quickly.

HOWEVER: The the failed reattachment left a residual epoxy edging that remained where the now peeled strip had been. And better, after a couple of days, this hardened completely, and has become a very effective traction surface that is both invisible and grabbable. Hey, that's another path to explore!