[Astro]

I think this was talked about earlier in the thread (or maybe it was the DC thread?) but i think both options would be good.
Adjustable regen on the throttle and a separate regen input.

I am aiming to make my EV as intuitive as possible for somebody familiar with driving a regular car.
So having a small amount of regen on the throttle would duplicate the engine braking effect you get on a regular car when you lift the throttle. It really is surprising how much i rely on that effect in traffic. I would find it disconcerting to lift my foot off the accelerator and have the car continue rolling at the same speed. It would also mean much more swapping my foot between throttle and brake in traffic.
Yes, i would get used to it and adapt but it would be nice to keep it consistent with what a regular car does.

Then for more regen i will be doing what Paul mentioned and putting a pressure sensor on the brake line which will give a variable voltage depending on brake pedal travel. Hopefully it will be possible to set this up so that the regen kicks in very early on in the brake pedal travel and increases to near maximum regen just as the normal brake pads start to bite the disks/drums,
So most braking would be via regen but any serious/aggressive braking would cause the normal brake pads to do their stuff.

This would also mean any failure of the controller would cause the regen part of the brake to stop working but the driver would just naturally press the brake pedal harder and the normal brakes would save the day. This seems the safest way , IMO.

It would also mean the controller wouldn't have to interface with the brake light and worry about when to activate the light. The brake lights would still be activated by the original switch on the brake pedal mechanism.
The slight regen on throttle off wouldn't require the brake light as the engine braking on a regular car doesn't activate the brake lights either.