[GreenKeys] Computer to teletype module...

[epvgk at limpoc.com]

On Sat, Feb 17, 2018 at 06:21:37PM -0800, John Nagle wrote:
>    Exactly, My design could easily be made by a PCB assembly shop,
> but it's not an easy hobbyist project.
> 
>    There are no through-hole equivalents for many of the parts
> in that design.  It has a specialized switching power supply which
> uses modern switching power supply components. Those just aren't made
> in through-hole. The layout around the switcher has to have very short
> lead lengths or it won't work at all.  Having been forced to SMD,
> I went as far as I could towards all SMD.  Once you're set up to
> assemble SMD, it's easier to place SMD parts than through-hole parts.
> 
>    If there was a market for 100 of those things, it might be
> worth having them manufactured.  Less than that, not worth it.

I ended up selling close to that many of mine (at cost, mostly just to
subsidize getting them built.) I bet there would be a similar sized
market for yours, especially considering many people have only a single
teletype and don't need or want to deal with a separate loop supply. 

For that matter I want to build one of yours, too. The power stuff is
great and it would make life easier bringing a machine to conferences etc.
> 
> which requires an external 120VDC power supply and an external
> USB to serial converter.  I built and used several of those.
> But surplus 120VDC power supplies are now hard to find.

I feel like a compact switching loop supply is another project that might 
be worth doing for greenkeys...


eric