Devo 7E addition switch questions

I recently bought a Devo7E and I'm looking at the mod to add additional switches. I'm specifically looking at the wiring for adding a pair of three-way switches, and I have a couple questions:

All the instructions I've seen shows a diode on each of the throws for each switch, rather that a single diode per switch on the common. Is there a reason for this I'm missing? I'd think only a single diode on common should be needed. I.e. the diode is to prevent current from flowing in an unwanted direction, but as current should only be able to flow between the common and one throw at a time in a SPDT switch all current should be controllable from just the common.

The extra switch mods seem to have started because of two unused slots in the button matrix, but the latest 3x2 switch mod appears to work by exploiting details of how a button matrix works, and no longer uses the NC slots. From a hardware standpoint, doesn't this mean the two NC slots are now open again for potentially adding a pair of two way switches (or momentary buttons) again?

Thanks.

Hi !
The one diode per switch idea should work from what I understand. I believe someone else did it that way too. Sadly I can't find a link.
I don't know anything about the ununsed nc slots. If we can add even more switches great
Have fun modding

I'm pretty certain the use of one diode installed on the center/common post per switch would be fine. The outer two posts can not come in contact with each other as both can not be in contact with the common post at the same time as you suggested.

I completed this mod tonight - very simple. However, I did use two diodes per switch.



The diodes I used are intended to be surface mounted, however, they function as expected.



Don't forget to edit the hardware.ini file so software is aware they are present. The "Channel Monitor" feature is a decent way to verify they are working with default values.

Here's a video of them working:

Thanks for the replies. I have some electronics background and couldn't figure out why there was two diodes per switch; I figured I'd give it the benefit of the doubt and ask first in case I was missing something.

As far as I can tell those two NC slots should allow two more switches with no issues, though TBH most of my investigation so far has been for a bit more complicated wiring (that would add a total of 4 three way switches and two momentaries, with a caveat).

I had some issues finding some basic info about some of the mods, so I wanted to make a set of videos when I mod my devo7e. Unfortunately I don't know how soon I'll have enough time for that extra work now.