Andrew Morris had a problem with a small rotary tool built in China. The tool fit nicely in the hand and was useful for precision cutting, drilling, and polishing. Yet for delicate work, the tool was in bad need of a speed regulator.
Andrew had developed an analog motor speed regulator back in the mid-1990s, but this time, he wanted the benefits of a digital regulator. The digital version was just as efficient, but it was less expensive to build and easier to assemble. The digital circuit also provided more torque.
Andrew Morris' microcontroller-based DC motor speed regulator brings control for delicate work.
Yes, it measures the back EMF after momentarily disconnecting the motor. This scheme would not work with a universal motor. You need to use IR compensation for that kind of motor. The analog version of this gadget, referenced in the article, uses IR compensation. A scaled-up version of that circuit would work fine with a universal motor, like the Dremel Moto-tool.
Also, why do you need to have extremely high speed for working on hearing aids. A Dremel moto-tool runs extremely fast without boosting the voltage. I'm afraid to do delicate work at high speed. Do you know something I don't? High speed would melt plastic parts.
What a cool looking kit, mrdon - that looks like a lot of fun. Thanks for the link, it makes me want to start playing with my PIC stuff again. Another thing I love about using Microchip products is the technical support that is available, their extensive documentation of their PICs, and their forum community. I have gotten some excellent help when I was stumped on a project that I was contracted to do and wound up making a great friend and partnering on the project with him that (speaking of patents) was eventually patented by the company we wrote the code for.
Nancy, I agree PIC projects are really cool and fun to build. In reading Andrew's Build document, the assembly language code used to monitor and control the motor is quite typical of Microchip. All of their microcontroller software reference design documents illustrates the target application with assembly code. Here's a link for a cool PIC Lab Development kit including the PIC10F microcontroller.
This discussion of the patent process is remarkably similar to what I experienced while doing engineering technical consulting for large corporations.....right down to the description of the witnesses and the many co-inventors.
I was routinely asked to evaluate patents for useful information. Often this evolved into equally simple ways in which the whole patent could be subverted.
Without offering any moral judgment, I'll simply note that my engineering career spanned enough years to see what was once ethically questionable becoming a common and valued engineering practice.
It may be at a patent was never as much of a strong protection in reality as it was in folklore. How could it be wit such a low level of international support?
My advice to startups is not to assign too much importance to patents. Lack of a patent should not be the deciding factor. It may be that more businesses failed to get started from fear of not having a patent than ever failed from patent challenges. In my opinion, the real value of the patent process is in the way that it promotes education and advances knowledge.
I would like to see the patent process continue evolving away from it's legal and protective roll and more towards becoming a vehicle for recognizing unique achievement and distributing new ideas.
One of the things we did at the R&D center was break other people's patents. We worked with the lawyers to find loopholes to use ideas that we wanted. This was not the fault of my former employer, but is common practice in big business.
So, yes Nancy, we did exactly what you're talking about. We would make some small change to get around the patent.
I looked into it with my portable trail obstacle small business (no one makes portable trail obstacles and hubby and I do all of the design work). We ended up just using a trade mark symbol for the phrase "portable trail obstacles" which would give us some ownership rights depending on what state you are in...and we could have done a patent pending for a small fee without actually going through the trouble of getting a patent - but as you said, it would be whoever had the deepest pockets would have control. Just not worth pursuing for a business run out of a tiny home office. Also, people can tweak their design enough for a patent to be issued to their design even if it was originally copied from yours...
It's a shame to have to say it, but IMO, patents are no longer a viable option for the individual, except in rare cases. I just wanted to stir up some conversation on the subject and see what came out of it. I also wanted to tell my story about what happened to the patent on my invention, which is being used in this gadget.
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