Probably the simplest similar adapter would have been a piece of insulation from a chunk of number fourteen copper house-wiring cable. From each foot of wire you could produce about 36 of the 3/8 inch long adapters, and at about 90 cents a foot for the two conductor cable it would have been quite cheap. But those spacers are a more elegant way to do it.
I thought of making a powered propeller hat a few years ago. I wanted the propeller to turn slowly enough to be able to see the blades (2 or 3 revolutions per second or so). I programmed a PIC to PWM the motor, but I found that there were a bunch of things that affected the speed (temperature, humidity, battery voltage...) and since I was trying to run at the hairy edge, it just didn't work very well.
This must be a magic adapter. The ID and OD are the same.
A long time ago I designed a fabricated part. The machinist insisted there was a dimension problem, I of course insisted it was correct. He later came in with a handful of metal shavings.
"Here's your part" I learned my lesson.
What are the engineering and design challenges in creating successful IoT devices? These devices are usually small, resource-constrained electronics designed to sense, collect, send, and/or interpret data. Some of the devices need to be smart enough to act upon data in real time, 24/7. Are the design challenges the same as with embedded systems, but with a little developer- and IT-skills added in? What do engineers need to know? Rick Merritt talks with two experts about the tools and best options for designing IoT devices in 2016. Specifically the guests will discuss sensors, security, and lessons from IoT deployments.