Enlarger-controller features you've never seen

[albada]

But as far as designs in general, I know the "sloped console" one does look nice on the surface. But it has one big problem from an assembly/internal-design point of view. You can't use the circuit board from the top panel to mount any of the front or rear connectors. So if any of your connectors are board-mounted, that means a minimum of 3 PCBs to make it work with front and rear jacks.

The first prototype of the Printalyzer Enlarging timer actually attempts to fit everything (panel, rear connectors, front ports) onto a single PCB. Of course now that I'm getting started on the second prototype, I've decided to split off the rear ports into their own PCB. Two real reasons for that... 1) To isolate everything that has to touch mains AC into its own board I can update/finalize independently. 2) Because it actually lets me reduce the case depth a bit.

Having two PCBs lets you have a sloped console! That looks better than a flat-top box and is easier to use. Assuming your rear PCB is horizontal, it can abut the left or right side of the case, letting you put the USB and footswitch connectors on the sides, which is probably more convenient for the user instead of having them stick out the front.

I've definitely gone overboard with TVS diodes in my designs, just to be safe. The most frustrating part with them, is actually finding single-line TVS diodes that aren't damn near microscopic. I'm now on the 3rd choice of diode with my various densitometer project PCBs, each time increasing the size a little, and they still look like specs of dirt when you look at them on the table without a microscope.

I was unable to find a suitable TVS array in a through-hole package, so I selected SMT chips with tiny legs. I straightened the legs with thin pliars, and carefully soldered thin wires onto them. After spreading out and attaching the wires to the perf board, the result looks like little smashed spiders, similar to "deadbugging".

 

[Craig]

Here's the fee schedule for the US Patent Office: USPTO Fee Schedule

For an individual person, which they call a "micro entity", the submission fee is only $44.00. Add $300 for search and exam, and another $240 issuance fee. That's $584. Double that for a "small entity", which I suspect means a small company. I can envision that somebody would be willing to pay these amounts to eliminate a likely future competitor, even with our low sales volumes.

The maintenance fees are $400 (micro entity) and $800 (small entity) at 3-1/2 years. Fees are higher in later years. Where did those $15,000 and $4,000/year numbers come from?

Mark

Those are only the government fees. Much like going to court after being charged with a major crime and being self represented, sure you can do it, but your chances of success are low. Similarly before the patent office, you can self represent as an inventor, but unless you know what you are doing, your chances of success are low.

Unless you are skilled in writing the application and doing a proper background search you probably will have your application rejected. Patenting is a highly skilled and specialized area, and like any other specialized discipline has it's own language and nuances.

It's also worth considering that patents are national. If someone has a US patent only there is nothing stopping me from making and selling the same thing anywhere else in the world. If you're a patent holder you also have to do your own enforcement, that can become very expensive in a hurry.

Generally speaking, unless you're a fairly large corporation, patents are not worth it. This from someone who has spent much of my professional career writing and prosecuting patents.