MobiFlight Community Support

Hello greetings to all this great community of passionate about simulators, I have a question and I am adding a switch with parking break function so I have no problem because it works perfect but I want to take it to another level, what I want to do is that when I apply the parking break and it is active when I touch the pedals with the differential brakes I do not disable the parking brake that always remains active while the swicht is on, how can I achieve that. I thank you for taking the time to read my post and you can help me, thanks

Hello willysim17,

Welcome to MobiFlight.

First of all something fundamental: it would be very helpful for us if you tell us which simulator (FSX, P3D V ?, X-Plane V?) and which addon (Standard, PMDG, Aerosoft etc) you are using.

For your project:
When cockpit construction, we usually have the disadvantage that certain things can not be recreated, as it is the case in reality. This is related to the technology of the components, which are controlled by events and then automatically jump to a predefined state. This can not be imitated so easily.

Assuming that a simple parking brake switch is used, it will not automatically jump back from ON to OFF when the differential brakes are applied. If your differential brakes switch off the parking brake, the parking brake function will be switched off, but the switch itself will remain in the ON position. Thus, the switch position would no longer match the function. This should be considered.

As far as Mobiflight is concerned, preconditions have to be set in the individual configurations that bring the desired results.

But there are solutions that achieve the effect you want:

1. You can create an environment by preconditions, which leaves the parking brake and the associated LED turned on, as long as the differential brakes are not operated.
If the differential brakes or one of them is actuated, the value of the parking brake must be set to 0, so that it is ineffective. The LED of the parking brake would then go out, but the switch would be in the wrong position. The switch of the parking brake must then be operated manually.

2. Instead of a switch (ON-OFF) you use a button. This button now activates a bistable relay, which takes over the function of your parking brake switch when the button is pressed. If the button is pressed, the relay switches and sets your parking brake. The associated LED turns on and indicates that the parking brake is set.
If a differential brake is now actuated, the bistable relay is triggered again and switches back to the original position. The parking brake is switched off and the LED goes off again. It must now be operated manually no switch here.
A suitable bistable relay would be e.g. HONGFA HFD3-005-L2 (5V, 2 coils) ~ 2 €

If you have any questions, please ask here.

thanks stephanHO for your prompt response specifically I am using FSX with the cessna 172 default and recreate the handbrake on how it is on the plane with a handle that pulls and squeezes the parking brake switch to activate that event there is everything ok , but I can't touch the pedal brakes as I was telling you because the parking brake function is deactivated leaving the lever in the pull position, I saw a friend once have his simulator with the same function only that he responded as really it would be in reality, but I lost communication with him a long time ago to ask him how he made his configuration if it was the way like the relay you say or through another one since in the bottom left you saw that he really did the function because it gave the messages that he applied differential brake and when he stopped using them he would be back in the parking brake and if he did not release the brake, the brake would not be deactivated.

Hi Guys

Basicly in not completly understand the thematic.

At first we must talk about how this brake should work.

I was in a B737 Simulator some time ago..... There the Parking brake was something like a mechanical "blocker" . So you not be able to set or relaease parking brake just with the switch. If you like to SET the parking brake you have to use the pedals (maby to 90% of maximum). BEFORE this point the parking brake switch was blocked mechanical. If you reach this "magical" point of force the switch start to be moveable. If you turn the parking brake switch NOW then it "block" the Pedal and parking brake was SET. The Pedal itself now not turn back to Zero Point..... It was "hold" in maby the 90% Position ( by this mechanic)

If you like to release the parking brake you also can NOT simply move the switch. You have to reduce the force on this mechanical by press the pedals again (more then the current 90%) a bit to "release" the mechanic ( maby to 95% of pedal movement) ..... Then the machnic was "free" and the switch swap back by a spring and you was able to release the pedals completly .... Wich mean the parking brake itself was also released.

I not know if this is realistic or if this was just a self build solution.

BUT: What i can say clearly...... If your Switch should interact to the pedals then you need a solenoid switch for parking brake ( that read the differential brakes to interact) ...... Or you need a mechanic (cogwheels, fen belt, rope etc) so the switch is physical connected to the pedals.

*********************
Maby you can tell us detailed..... How should the system look like when you SET parking brake...... And how should it look like when you released it. Maby we find a interesting soluton.

This is how I understand it:

Willy wants to have a Cessna 172 like parking brake.
When you set it, you first push the rudder pedals to apply brake and then you pull the lever under the yoke towards you to maintain this position. You can only pull the lever well if you push the pedals first and take away the tension on the system.

To release the parking brake you step on the pedals again, push a bit and this takes off the tension on the lever so now you can pull it out a little and release the parking brake by pushing the lever back all the way in.

Problem in FSX and P3D is that using any differential brake input releases the parking brake.

Problem in FSX and P3D is that using any differential brake input releases the parking brake.

If you use the "Point ." key that simulate a 100% Brake input i agree.

What i never test is to use the FSUIPC (RegVersion) Axis for Brake Left/Right ..... Or maby if existing the Sim Internal Axis settings.

Does the Parking brake also release automaticly if you just use the Axis ( less then 100% ) ????

Any differential brake input releases the parking break as far as I can say off the top of my head.

Hmmmm.

Then a solution can be the reduce of range at this axis.
In FSUIPC we be able to "split" a Joystick Axis completly custom.

Lets say..... Axis (Poti) have a Range from 0-100% ....... Normaly Brake Input also goes from 0-100% simultary .
Now we reduce the range of Poti ..... 0-80% so the last 20% are no longer in use.
We set the brake Input to this 80% ..... Means
Potti 00% = Brake 0%
Potti 40% = Brake 50%
Potti 80% = Brake 100%
Potti >80% = NO INPUT

To SET the Brake he press the pedals "over" the 80% Position ..... And mechanical "Block" The Pedal by the Parking Brake Handle. ( Somewhere in the 80-100 Position)
The parking Brake itself is set by a microswitch in the Handle.
If my logic is correct then a Touching of Pedal now not release brake cause its over the 80% Position and no longer make inputs to the differential Brake.
To Release the Brake he just need to "Unlock" the handle so the Pedals can move back.
After reaching the 80% Point backwards 100% Brake Input is set and this already release the Parking Brake then...... Or we use again a switch input in the Handle to do this.

Not sure if this work...... But maby a idea.

hello thank you very much for your answers sorry for not answering before but I have been entertaining assigning buttons and encoding arduino seriously this is great I am new in the environment of this powerful tool of mobiflight I like, even make my own magnetic compass and the brakes I will use linear potentiometers to play with the percentage as I recommend it since a swicht is too simple to want to keep them activated always, because a small brake pulse deactivates the parking brake, my question now is what potentiometer value linear recommend me understand that there are 50K 75K and 100K but as I am new to this I would like to know your opinion, success and good day

Hi Willy,

linear poti is great but mostly used for analog inputs are potis with 10k ohms. Other values only if recommend by the manufacturer.

Does the Parking brake also release automaticly if you just use the Axis ( less then 100% ) ????

By default yes, to be exactly >75%. Change "BrakeReleaseThreshold=xx" in FSUIPC.ini to set your own likes. Value 0 will deaktivate this featuere. More in FSUIPC Advanced User Manual.

Anyway it´s not a realistc behavier of parking brake. Like Pizmann said, without pedal pressure the brake leaver will not hold. To release brakes pedals must be pressured too. I think this is allso an savety aspect. Nobody wants a huge mass of tons out of order due to a accidently leaver movement. Feets has to be on pedals not elsewhere.

To simulate a parking brake, its nessesary to connect pedals and leaver. This can do in a mechanical way or electrical. For example with a bowden tire and a blocking mechanism on the leaver. Easy, but may difficult on consumer pedals. A pure electical solution will need a selenoid to hold the lever up. All in all, it´s not a big problem to realize it.

Greetings
Gert