VANCOUVER — The strangest collection of projects come through Robin Jeffries’ door.

There was the tennis court ball sensor, the Bombardier Ski-Doo, the electronic drum kit, and the medicine-dispensing skin patch.

“It was kind of fun when a guy sent us a skateboard with a motorized pair of wheels on it and asked us to make a force sensor that would act as an accelerator for it,” Jeffries said. “Longboarders like doing downhill, but hate going uphill.”

Jeffries’ Sytek Enterprises Inc. is something of a magnet for inventors. Most inventions need an interface for human interaction and Sytek (ISO 9001-certified, with 32 employees) makes screen-printed electronic overlays that do just that — think of the touch pad on a microwave oven.

The company also uses a proprietary polymer ink to screen-print “force sensors,” which recognize the amount of force applied to an electronic drum kit, for instance.

“You can take the pressure applied to the surface as you press or slide or rotate your finger, and translate that electronic signal into a sound, or a volume of sound, or a brightness of a light, or some other point that’s a threshold,” Jeffries said.

Inventors or corporate engineers often phone in with cloak-and-dagger queries.

“Sometimes we will have guys who won’t tell us what the thing is for,” said sales manager Kirk Hutton. “They are afraid we’ll steal it from them. So quite often, we’re working in a vacuum.”

One customer in Japan sends encrypted emails with separately supplied passwords, Hutton said.

“The first illustration was very vague. It looked hand-drawn,” Hutton said. As trust grew, the requests became increasingly detailed. “Now it’s not just a flat sensor. It has to go over a bend. And now it’s actually smaller than they said it was.”

Jeffries takes the circumspect approaches in stride.

“It’s exciting getting a phonecall and then finding out that you’re making a product that is new to the world. It’s like opening a Christmas present.”

And while others might be reluctant to take small, experimental projects, Jeffries encourages them.

“We’re quite happy to make five of something and help in the design,” he said. “The majority have turned into large production runs. It’s surprising how successful people can be with the simplest of things.”

Take the Livescribe pen, which only contains one force sensor and will record and play back “everything you write and hear.”

“We made half a dozen to 20 parts in the beginning. They now order 15,000 parts every month.”

Indeed, Jeffries started his entire “force sensor” division, Tangio Printed Electronics, as a result of one prototype job.

“I had a phonecall one day from a scientist/inventor who wanted me to make a product for him and he didn’t explain very well what it was other than the fact that he wanted it to be the length of a tennis court.”

Turned out the Washington state man had invented a “force sensing” ink which a client wanted to use to sense whether a tennis ball was in or out of play. The ink was to be sandwiched between two carrier materials and placed under a tennis court surface.