dapinky wrote:If you need power to operate the handbrake, then there is always an element of 'power failure' (either sudden - fuse? - or not-so-sudden - flat battery) to exist, but i can't really see it as a problem for most people. - Perhaps a second power feed (fused) directly from the battery (or elsewhere), through a 'hidden' switch will overcome the 'unexpected' failure bit????....................
..........As far as the need to have the footbrake on to dissengage the handbrake, living on a hill, it is an everyday occurrence that i need to do a hill-start. If i want to drive away, I only have 2 feet, so can't see how I can have the right revs to pull away, whilst holding the clutch at the biting point, and still manage to operate the footbrake to get power to the handbrake - unless I'm missing something?.......
.....Personally, I'd favour an electrical feed NOT from the footbrake, but that's just MY preference - and easily overcome if/when I do the installation
Missed anything? Just that in what I've suggested regarding the "foot-on-the-brake" would only be required to engage the handbrake. Nothing would be required to disengage other than pushing the switch. So, I'm thinking that takes care of your hill start issue in that you'd use clutch and accelerator with your feet and just hit the brake button causing the brake to release over a second or so. I'm thinking (imagining really since I don't use the handbrake for hill holding) that the ebrake would actually make this whole process much easier then grabbing the lever - just hit a button.
I don't know how you'd ever overcome the flat battery issue on an electronic brake really. I'm sure it applies to most cars with them. I've just read on a Subaru forum that their manual says that in the event of a low battery the parking brake can't be applied nor released. If we wanted to get real fancy you could add a very small battery with enough juice to operate the brake once or twice I suppose.
Not sure anyone knows about this auto adjustment nor pays any attention to it. I certainly would ignore it and, if necessary, just incorporate a few flicks of the ebrake button from time to time to deal with it as you've suggested. As for the "safety" being from the brake switch its all I could think of right now as a way to ensure you're not driving down the road when some dumb passenger (or better half - or child even) says "What's this?" and hits the button causing untold amounts of grief. I figured that "one" way of preventing that would be to have your foot on the brake first (likely not going too fast in that case). But, it could be ANYTHING that makes sense of course and I'd love to hear alternatives. I had also though about the need to hold the button down for a second or two as a safety feature as well.
GeoffSmith wrote: ............Your switch needs to be two position like the window switches rather than the pushbutton type you've shown Blair.
Surely there are two cases to consider: You need to be able to activate the brake even with ignition switched off and you could use the VSS output to disable it to avoid accidentally applying it if the car is moving, although if your brakes fail you might regret this feature! Conversely, I think you should only be able to release the brake with the ignition switched on.
What I was thinking of using was a latching SPDT switch with an LED to light when the brake is engaged. I like the latching strictly as an additional visual indicator that the brake is engaged (like if the battery's dead). What I've seen so far from manufacturers of these actuators is control through a rocker switch with each position (2 position switch) moving the actuator in different directions. All the actuators I've seen so far control the motion simply by reversing polarity. to the 2 wires on the actuator which would be what the rocker switch does of course. I've seen some that are also momentary rockers that make you hold the button down the whole time to extend or retract the actuator but I don't think we want that at all. I can't think of a case when you want only partial application of the brakes but, if so, it would be easy to use this switch (ugly as it is) instead of the nice LED one I'm looking into.
Activating the brake with ignition off would have to be the case for sure. Another thing to potentially draw down the battery but at least there's no draw when the actuator is at rest- only while in motion. I agree about the VSS being problematic. There may also be a case where your brakes outright fail and all you have is the handbrake button. I could have the engineer I've used before (and who I would turn to for the window switch project) create a module that could sense the vss signal and then add a delay (if the car's moving) of a few seconds before activation as a safety measure (gives you a few seconds to slap the hand of the offender and hit the button again). The other thing, which could be the easiest to do, is to simply locate it in a out-of-the-way place so no one can get at it or recess it (as I might do) just to make it so you can't hit it accidentally.
Again, ideas welcome!
The Volt has a lever/button actuated parking brake, which works great---it also releases automatically if you press the throttle when the brake is applied and the car is in a moving gear--which works well if you want to just use the e brake for short stops here and there; I just brought it up to get you thinking about that detail; I'm sure the drive-by-wire helps as it's all in the programming...
