On-Off switch for rotors

[Robdjee]

Dear Kerbonauts,
 

I seem to have trouble with robotics. I get by, and the parts are great but i would like to find a way to use a single button (non axis) as an on-off-switch for rotors. I would like the off-state to be locked.
The action group options for rotors are somewhat confusing. I find it weird there is no simple ''on-off'' option.

Locking an engine and then using a button to enable motor drive or motor power and unlocking the engine does not work. I think because you cannot set the rotor as braked before launch. So you will simultaneously brake and start the rotor.
Braking ≠ locking

You can toggle locked state with a button but:
-One cannot lock a moving rotor. And,
-One cannot start a locked motor. 

You can turn the motor power off with a single button but:
-then rotors continue to idly turn until friction stops them. 

You can toggle brakes with a single button but:
-One cannot toggle max-min values of RPM or Torque with a button (i know, you can momentarily cycle between those values with an axis control).
in other words, this is no way to start the engine.

The best way i figured out is; somehow increase torque limit for a rotor and then use a brake toggle input as an on-off toggle.
I have used main throttle input as an RPM or torque limiter. This works. And to my knowledge, this is the only axis control that has some kind of ''memory''. But in complex crafts i may need to reserve the throttle controls for other systems.

Is there a way to increase torque limit in the VAB or SPH (other than axis contols)?
It is my understanding that you can only set the max torque limit in the VAB or SPH (engine size). Is that correct?
Do i make sense?
Do you have any other thoughts or ideas?

Kind regards,

Edited October 9, 2019 by Robdjee
readability

[AHHans]

2 hours ago, Robdjee said:

i would like to find a way to use a single button (non axis) as an on-off-switch for rotors. I would like the off-state to be locked.

Sorry, setting locks is bugged, quite often the lock does not get set because "part is moving" (even if you can't see any movement, there are no external forces acting on the part, and the brakes are set). So you can't have a single toggle switch that works reliably. What I do to reliably set the locks, is that I assign the "set lock" to an action and hit that button until all locks are set.

(I think you already meant that, but I also put it in my words:) The brakes are also a problem: you can also toggle them (which actually works reliably), but you cannot start with the brakes set or with the rotor power on. So if you toggle both once then the brakes get set and the motor power turned on., and here the brakes win. What you can do there is to keep the brakes of the rotor also in the "Brakes" action group and tap the <B> key when the motor is on. Tapping the <B> key will always set all brakes and then release all brakes, so afterwards the brakes are not set.

If you do want the locks, then you can set up a KAL sequence like the one below. That will when going from left to right:

• try to set the lock a number of times (if it was already set or gets set before the last attempt then nothing special happens)
• release the lock (this always works)
• toggle the brakes (see below)
• turn up the torque limit

So once it played from left to right then the rotor should be "on". If that set the brakes then you might need to tap <B> to get it moving...

Playing from right to left it will:

• turn down the torque limit
• toggle the brakes (I assume it was moving before that, so that should set the brakes)
• release the lock (well, this shouldn't do anything)
• try to set the lock a number of times (trying more than once to set the lock increases the chance that it actually gets set, but there is no guarantee!)

Depending on the inertia of the stuff attached to the rotor you may need to give it more (or less) time to come to a stop before any attempt to set the locks will succeed. To stop the rotor you can also set the RPM to 0 and keep the motor power on instead of using the brakes. But that will uses the motor torque and not the stronger brake torque to stop the rotor, so I think it won't work as well.

[Robdjee]

@AHHans, thanks for your suggestion. This might work. Too bad it is still rpetty complicated abd without guarantees. 
There is no way to max or turn off RPM or Torque with a single key is there?

[AHHans]

10 minutes ago, Robdjee said:

There is no way to max or turn off RPM or Torque with a single key is there?

Well, "Toggle Motor Power" toggles the torque. But as you said, that won't stop the rotation on its own. And having several "toggle" actions on the same button has the problem that they become out of sync (or start out that way) .