The way the video describes the controller in the trunk, I believe it is not interfaced directly to the car. I kind of assumed it uses an accelerometer to notice the car is moving forward and engages the DC motors. If this is true, I would imagine that the same accelerometer could notice that the car is braking.
Not sure why the trunk mount is relevant for interfacing with the car. The brake switch signal activates your brake lights, those are typically at the rear of the car :)
Admittedly, for a universal application you want to interface with as little of the car as possible.
That said, in the US all cars made after 1995 comply with certain On-Board Diagnostics protocols (OBD-II) so you can interface with several standard systems.
One such sensor available in OBDII is the VSS or the Vehicle Speed Sensor. Check out a device like the Scan-Gauge[1] to get an idea of other sensor that can be interfaced with universally. It would be trivial to run some wire under the carpet and plug into the OBDII port to give the hybrid system access to all kinds of engine & sensor info.
> I would imagine that the same accelerometer could notice that the car is braking.
It would not be able to tell the difference between braking and simply slowing down, for example going uphill - or worse, driving in water - hitting the brakes when going through standing water can be disastrous.
As for the accelerometer detecting moving forward it has some nasty feedback going on there, since it detects its own motion. Plus imagine going downhill and the read engines think you hit the gas so they cause you to go even faster.
That said, it should be possible to interface with the engine there are plenty of signals that can be used (throttle, rpm, etc).
> it should be possible to interface with the engine
Agreed. I was simply saying that from what I got from the video, it is not interfacing with the vehicle. Maybe it should be but it seems that is not what they are building. I'll leave it to the people that have been working on it for 4+ years to make that decision as they certainly know a whole lot more than I do.
