A physical tool to bridge the gap between pixels and people
I took all the the information I gathered from the research into how people really hold and touch their phones, tablets and computers, and made a tool to inspect and create designs that are more human centered, the 4ourth Mobile Touch Template.
Because you cannot design with only pixels. Your finger cannot be measured in pixels. Your eyeballs see photons, not pixels. And more or less of them depending on how far away you get from the screen. We need to set aside things like the iOS 44 px cadence, and any other guidelines that are resolution dependent. We need to get off the computer, and try things out on real devices.
Now in the ninth full iteration, it has been out for over 14 years, and is used by over 5,00 designers, developers, and testers in over two dozen countries, at companies like Google, Microsoft, R/GA, Thomson Reuters, Nokia, Honeywell, Nordstrom, Sprint, AKQA, Verizon, Shopper's Drug Mart, Costco, GoPro, Capital One, Home Depot, Cognizant, Terra Networks, Citrix, Human Factors International, and many more.
It has changed over time to be more an inspection tool, and is now two cards, one of rulers and type size measuring, and the other all about touch target sizing.
We're actually up to v7.3 now, but the changes are minor production things to make it easier to read, fix errors, etc. It keeps evolving but the principles stay the same.
Just hold it over the actual product, or export your drawings to the phone or tablet, and measure directly to check your math is right, or confirm your suspicions that something is too small to be easily usable.
Credit card sized, you can keep it with your design kit or in your purse or pocket so it's always around at meetings, or when you travel for work.
