(little) gaps in the market.

[Galenbo]

Hello, sometimes I need some little device, pcb, signal adapter, and can't find it on Ebay or Aliexpress, while it's flooded with different similar products.

Practically, I'm looking for a 4/8/16 channel input protection/filtering/optocoupler input board, and all I find is output boards for microprocessors.
http://www.ebay.com/sch/Relays-/36328/i.html
4/8/16 times an optocoupler with some diodes and RC filter will do, it will be used between the light pushbuttons in a home and the PIC processor.
A board with also place for an SPI Port Expander will even be better.
Everybody who is playing with Arduino or other uP could use it, for connecting end-loop-switches for example.

At the moment my time is needed on different things than developing that thing myself (and eventually distributing it)
but I will surely do this when the moment is there (and the gap is still there)

Did you also bump into a (little) gap in the market? Did you fill it yourself?

[splin]

At the moment my time is needed on different things than developing that thing myself (and eventually distributing it)
but I will surely do this when the moment is there (and the gap is still there)

Sounds good, but unless you have deep pockets presumably you'd have to sell them in the same way as Chinese suppliers - illegally without CE certification - except they are practically untouchable whereas you could be investigated and prosecuted if you didn't have the appropriate technical files demonstrating compliance.

You have to admire the EU setting up a system (or at least as implemented/enforced by the member states) which severely disadvantages small European companies to the advantage of their Chinese competitors. And that's without the additional handicap of our postal services delivering Chinese goods, apparently for a fraction of the price they charge domestic customers...

[JoeN]

Out of curiosity, what are you envisioning a channel on your input board would look like?  MOV, zeners, optocoupler, small transformer?  What parts?  Just interested in what makes for bulletproof input protection for, as an example. an industrial environment or input that gets connected to a phone line that runs out of the house and might get hit someday by lightening.

[m98]

I'd try a gas tube spark gap, ptc-fuse, hrc-fuse, zener and an optocoupler. That should also work for moderate-speed one-way busses.

[codeboy2k]

There's a big thread here too, with plenty of ideas tossed about.

https://www.eevblog.com/forum/microcontrollers/robust-microcontroller-input-protection/

[Galenbo]

Out of curiosity, what are you envisioning a channel on your input board would look like?  MOV, zeners, optocoupler, small transformer?  What parts?  Just interested in what makes for bulletproof input protection for, as an example. an industrial environment or input that gets connected to a phone line that runs out of the house and might get hit someday by lightening.

I had the idea of taking the schematic I added as attachment in the first post.
It is the schematic that is typically used in a PLC.

Clipping diodes, RC, opto. Done. The thing I would definitely buy instantly is the PCB.
So I can choose witch R and C, expander or not, SPI or I2C, all that by choosing components and/or soldering bridges.

[Galenbo]

But this tread is about other gaps too. I found one in another tread recently:

https://www.eevblog.com/forum/chat/how-to-notify-someone-in-case-of-an-emergency-ice/

You need a home device with a big reset button and a sim card.
When not reset for 12 or 24 hours, it starts calling numbers on the list, starting with you and ending with 112 and 911

Does such a device have a name?  Is there a commerial one on the market?