Hi,

I got a pair of car-tube foot-pumps cheap in a sale and joining the tubes together and removing the springs  - I have made a super set of pedals.
Now I have to wire it in! I would like to use the guts from joystick - which one is best to dismantle please? I hope to still use the joystick afterwards as a joystick.

thank you - volunteer

volunteer,

Welcome to the Homebuild Cockpits section.  Here's a "Joystick Hack 101" starter thought for you:

A "joystick hack" is one of the "standard" ways of getting a set of home-made rudder pedals to interface with the computer.  Others include using more specific (and expensive) specialized interfaces like Phidgets cards.  

To do the joystick thing, you will have to first dis-assemble it.  So I can't really see how you would use it as a joystick again afterwards.  At least not EASILY.  I can think of ways to do it .....but it would get very complicated and require some REALLY clean electrical and mechanical work.

For the joystick's built in axis control, a cheap joystick uses two potentiometers (variable resistors) to control the X and Y directions.  A twist grip joystick adds in a third potentiometer for the Z axis (usually assigned to rudder).  And if the joystick also has a throttle control, that is yet another potentiometer.  A few momentary contact (Normally Open or N.O.) buttons usually round out the possible controls on joysticks.  (You can also then remote mount some N.O. buttons to connect to those original button locations... but we'll skip that for now.)

For a set of somewhat realistic rudder pedals you will need THREE joystick axis controls.  One to assign to the Z axis (the rudder left/right function), and one for the proportional toe brake on the left pedal and one for the proportional toe brake on the right.  

On your "tube pump pedals"... how will you machanically address the toe brakes?  The individual pedals need to tip forward when you press down with your toes and spring back to the non-pressed position when released to emulate the real ones.

Most joysticks use some type of rotary potentiometer (or "pot" for solder-jockey shorthand) to make the resistance change that is turned into position data by the stick's electronics.  These are "dial type" units.  SOME joysticks use slide potentiometers.... but they are rare.  Pretty much ALL joysticks use what is called "linear" potentiometers.  This means that the total resistance of the pot is divided equally along it's range of travel.  Turn it 1/2 way and the resistancve is 1/2 the total possible...and so on.

To "hack" the stick for your pedals you usually have to use a NEW potentiometer for you pedals.  Often the originals are tiny printed circuit board (pcb) mount ones that are hard to work with for full sized pedals.  The first step in selecting the correct NEW one is to find out the actual resistance of the originals.  Usually to do this you need a multimeter although sometimes the value is printed on the original pcb (printed circuit board) at the point the resistor is mounted.  To test it you unsolder the original and test it with the multimeter and find that (in many cases) is is a 100K Ohm pot.  Then you go to the local electronics parts store (or online) and order three new ones of the correct physical size and type.

The mechanicaals are VERY specific to your own setup....and I can't comment a lot on that.  You need to hook the pots up so that the movements of the pedals and the toe brakes cause the pots to turn.  The best thing is to set it up so that they use almost ALL of their range of movement.  This gives you the most "sensitivity" in the sim.

Once you have the mechanical stuff solved, you run wires from the new pots on the pedals back to the original locations that they were soldered on the original joystick's pcb.  Make sure that the connections are well soldered and that you don't get solder bridging together any of the traces (little copper roads on the pcb) inadvertantly.  It is likely best to solidly mount the original pcb right onto the pedal structure base somehow...... and then just run the USB cable back to the computer.

Once that is all done, you make sure Windows still "sees" the joystick and then assign each axis to a function in the sim and calibrate it like any other joystick.  

Look in this forum (older pages) for other threads that discuss building pedals for more ideas and some pictures.  Ozzy should have some stuff soon for you too.

Good luck.  Welcome to the insanity.  Hang onto your wallet; you've started on "The Journey"  .  And please post photos here at SimV for all of us to follow your progress.

best,

.....................john

Thank you - I need to digest all this!! what attracted me to the pedals was they were megga cheap - and they are robust and look the part. With the air pipes joined - one pedal goes up and the other goes down. I think oil would be better than air, as the action when joined is a bit spongy. I never thought of toe brakes. Just the idea I had in the store - when I saw the foot pumps at ten $ for two got me thinking.....

Rather than using the air to move your potentiometer (getting a headache just thinking about that), you might rig some other sort of simple linkage that moves when the pedals move. Much easier and cheaper.
JB is on to something brilliant, but I'm guessing you're not looking to go quite that far...

The pump-pedal idea has potential, that's for sure. The movement of your feet will be more similar to braking than moving the rudder, but maybe not very much so.

As for hacking a stick: don't plan on using it again as such, although that's do-able. Rather than go through all the trouble of setting things up so you can restore the joystick to its former state, you'd be better off getting a real cheap joystick and gutting it.
If you're only using it for rudder control, it can be a pretty crappy joystick.