E-mount electronic protocol reverse engineering

Entropy512 wrote: Hank - I believe that was similar to an approach someone had for a REALLY long EF extension tube that they 3D printed. It had some ideas for going forward whenever I get back around to this. The lens side of almost any mount interface is going to be easier - your strategy would probably work well for most mounts. The problem is the camera side (or for an adapter, the "adapter to lens" side), since those have spring contacts. At least one person has succeeded with pogo pins (the EF megatube guy), although it was really finicky. AHA - found it - https://sherlock-photography.github.io/canon-extension-tube/ I just haven't had the time to alter this basic idea to my needs.

Nice reference. I 3D-print a lot of adapters including the flange parts, and most of my designs print in as few pieces as possible without supports, but that does make the design harder than using an assembly with commercial flanges. I definitely think wire-wrap is better for the connections than straight soldering, but the E breakout extension tube I'm using now was just soldered.

My brother has had some luck using pogo pins on various other projects, and that's certainly a more "official" possibility for the lens end of the adapter, but I was thinking it might suffice to have a bit of springiness to the mounting of the part that holds the contacts. It's quite easy to 3D-print a leaf spring. Anyway, no time to explore this space right now....

BTW, all of this stuff is really finicky. The tolerances needed for alignment of the pins with full contact area are just barely within what a cheap extrusion-based 3D printer can do (gaps between pins are just barely printable without having to drill 'em out like the adapter you reference). Last month, I bought a Mars 2 Pro resin printer in the hopes that I can get about 5X tighter global part tolerances, but I haven't even done a test print with it yet. Pogo pins should pair better with resin prints.

Just to be really technical about this, even pogo pins are not really the officially correct mechanism for a set of contacts that rotate into position -- although they are used by many cameras. It should really be spring-loaded ball contacts... which are even harder to deal with.

Edited by profhankd - 22 January 2021 at 13:56

https://www.youtube.com/watch?v=R_In4C-jsyI

https://www.youtube.com/watch?v=2sM3TctTJBQ

https://www.youtube.com/watch?v=j1_O2dGkk3s