Heng Long recoil trigger

[Scoopey]

Hello there folks,
Hope you can help me..may be this has been covered before but I just can't find it.
I'm looking to convert a Heng Long recoil unit. Based on the idea to turn the unit 18- degrees I'm altering the mechanics so they work backwards instead. Anyhow despite my electronics being somewhat rusty I want to trigger the recoil and gun fire with the "K" button. I'm assuming I'll have to take a signal from the connection responsible for the track recoil/canon fire sound.
Does anyone know which connection this is. If my thinking is right it would be the same signal used by the add on circuits that stop the track recoil.
This leads me onto another question. If you operate the left stick up it activates the BB gun motor (which I'm removing). As the pellet fires the tracks recoil again with the canon sound. What I'd like to know is how the sound and track recoil are triggered in this instance. I've seen a micro-switch on the BB unit and was wondering if this was responsible.
Essentially my ideal goal would to have the left "Up" stick function operate the elevation motor in the opposite direction to the down stick movement. With a couple of microswitches, a pair of MOSFETS and a relay this could translate to up stick = barrel up, down stick = barrel down. However if whatever triggers the sound and track recoil when firing the BB gun is electronic in nature as opposed to being mechanical the result of raising the barrel would fire the gun!
If anyone can help me out in understanding the gun trigger(s) I'd be much appreciated,
Regards
Steve C

[MichaelC]

My HL is rusty (all Taigen and Clark now) so I can't quite remember exactly what happens when you push the button K but I know that the microswitch triggers the sound and hull recoil i.e. when the BB/Recoil motor pulls the pin back it will trigger the microswitch and that's how you get the cannon sound and the hull recoil. That's the same reason why if you recoil/BB motor is stuck the microswitch stays on and you will keep getting cannon fire and hull trigger/shudder.

I think on the BB version the K button will trigger the firing sound and the hull recoil but no BB shots, and on the IR version it is exactly the same as pushing left stick up. So you might have a working idea here provided that it is a BB version......... Like I said, rusty on the HL radio now.......

[Scoopey]

Thanks,
That means if I'm right the add on circuits used to prevent the track recoil will probably tap into the signal feed I need.

[MichaelC]

Well I guess that is one way of getting to it if you have an ATRC/Dragon. Basically they get the signal to Fire/Recoil and temporary kill the power to the motors so there is no track recoil. I think you might be go around this the long way though. I mean if you want to ascertain that Up left stick won't trigger the firing electronically other than the microswitch on the barrel which I don't think its the case, just disconnect the barrel motor and connect it to the elevation motor an see what happens. if it doesn't then Bob is your uncle. You just have to figure out the polarity switch for up and down and K switch should still fire the main gun.

I think that is what you are getting at, right ?