IBU3 - correction to airsoft functionality

[Peregrine]

This is a continuation of discussion from a "for sale" thread here viewtopic.php?f=18&t=20231
It's the answer to the request from tomhugill.

Little summary first:
IBU3 does not correctly handle airsoft functionality. IBU3 user manual claims in its features list “Direct control of standard HL/Taigen recoil /airsoft”. This is a false advertisement, because the HL airosoft does not work correctly. The solution there is like a duct tape on a falling apart plane. Yes, you can set the mechanical recoil time to the length of time it takes for the airsoft motor to fully extend/compress the springs and shoot, and yes, you can play around editing the sound file so after 2 hours of work maybe you can get it synchronized with the exact time the BB comes out... but, there's no way to offset the standard recoil servo so the recoil would start with the BB shot (it only works for Taigen recoil), and more importantly, there's no feedback from the airsoft unit, so the IBU3 CANNOT reliably tell what position the airsoft unit is in. You can set the airsoft to the beginning cycle, and then set the mechanical recoil to the length it takes for the airsoft to extend and shoot. Let's hypothetically assume we set this to 1500ms, and it works. Then you fiddle around with barrel movements and by mistake you go too far up which now starts the gun shot motion, because it's all on the same stick! You let go of that gun shot, because you really wanted to move the barrel at this point, and guess what, your airsoft is no longer at its beginning cycle, because the airsoft motor moved a little. So now when you try to shoot, the shot will come a little sooner, let's say after 1300ms, because your airsoft was already slightly moved before. Next time you fiddle around with barrel movements and go passed the barrel up and by mistake move the airsoft a little, it may take 700ms to shoot the BB next time you try to shoot. And this can continue on, and on, so all in all, your shots will never be synchronized, and you won't even know what position your airsoft is left at after the shot. Do you really want to store your tank with the small outer spring extended and the big inner spring compressed for few weeks or months?

The proposed fix:
These are partial extracts from my emails to Ivano (slightly modified to fit this post better), which he totally ignored.

Explanation of concepts used in the modification logic (lower):

* - What I refer to as the "airsoft trigger switch" below, is the airsoft microswitch, also called a recoil switch, standard part of the HL/Taigen airsoft unit. I think the "trigger" term suits its functionality better in this content.

** - Obviously, I don’t know the circuits on the IBU3, but there has to be a port we can spare designate to accept the airsoft trigger signal. The most logical would be 2 pins of the xenon port, because if someone is using xenon then they can’t be using airsoft in the same gun, and vice-versa. So you could create additional configuration to allow selecting xenon OR airsoft functionality on the same port. And if the xenon port is impossible to use because of the circuitry, there has to be some other 2 pins you can designate this functionality on, even on the expansion port if nothing else.

*** - I added the word “positive” to the airsoft trigger offset setting, because we can only add a delay to the trigger (and if no delay is needed, that setting can be left by user at 0). Obviously we can’t do a negative offset, because we can’t predict when the trigger input would come, so we can’t start sound and recoil actions before the trigger input. Any negative offset, the user would have to do manually by adjusting the switch arms on the back of the airsoft unit.

Modification logic:
Step1:
Add config setting for user to select “airsoft trigger offset (positive)”.***
Add config setting for user to select “xenon” vs “airsoft”.**
a. If xenon, then no changes, leave all as it is now, goto StepEND
b. If airsoft, continue to Step2 below

Step2:
Change citruitry logic relative to 2 pins of the xenon port.**
Pin1 – constant ground output to the trigger switch (personally, I prefer to connect this to another ground pin, like one of the servo ground pins, so I don’t have to run redundant wires through a slip ring to the turret, but for other less understanding users, it would be better if you kept those 2 pins next to each other, so they could connect both trigger switch wires together).
Pin2 – trigger input from the trigger switch.*

Step3:
If receiving input from receiver to shoot main gun, initiate ONLY ground output to airsoft motor (motor starts rotating, extending the spring) for the length of time defined in the “mechanical recoil time” in user settings.

Step4:
If received ground signal on the trigger input, wait the amount of time defined in “airsoft trigger offset (positive)”, then do all steps below simultaneously:
a. initiate gun fire sound.
b. initiate recoil servo motion.
c. stop ground output to airsoft motor.

StepEND
end of logic

Last explanation:

- Action in Step4 c. (stopping ground output to airsoft motor) is necessary, so the motor would not continue moving the springs anymore. If the trigger switch is closed, it means the small spring is extended all the way, and within micro or milliseconds the airsoft will fire. So the “airsoft trigger offset (positive)” setting is there to make sure the motor motion is stopped right after the shot is fired. If this is not done, then every time we shoot, the motor will always work the same amount of time as defined by user in “mechanical recoil time”. The user should set this to the length of time it takes the airsoft motor to move from starting point to the time it shoots. But because the shooting is done using the same stick as barrel-up movement, it’s possible for the user to often move the stick up passed the barrel movement, and that sends a signal to the airsoft motor, but not long enough to move it the whole distance because the user would stop within a second when he sees he’s not getting the right action he wanted. That happened to me a lot fiddling with the sensitive barrel movements. So eventually, that airsoft motor may be moving many times little by little, extending/compressing the springs from the starting point, so when the user finally wants to shoot, the starting point of the motion is no longer when the small spring is short, but it may be mid point or maybe even when the small spring is extended. So the shooting results will vary a lot, and there’s no control over which point the springs will be left at after the shot. And we don’t want the springs extended/compressed for weeks when the tank is not used. So the best option is to make sure that motor stops moving right after the trigger switch closes. And then we can be always sure the springs are in their default positions right after every shot. And if the user sets the “mechanical recoil time” too high, it won’t matter, too, because the movement would stop when the trigger switch closes, anyway.


Sorry for some redundant explanations above, but this last one came from the email extract, and I didn't feel like editing it anymore, so it wouldn't loose the meaning.
Other than that, like I said, an easy fix.

[Peregrine]

[deleted (updated content of the first post, so this explanation is no longer necessary)]

[tomhugill]

Thanks for the explanation

[Peregrine]

Hope it helps someone fix this functionality in the future.
I'm switching to asp. Kevin doesn't run away from any problems, and improves his product continously.
Wish I could say I had good experience with IBU, like few other people here. Too bad that didn'the happen.

[theibuman]

The FW update (available for download within days) will fix this issue, we will take care of the airsoft switch and play the "boom" in sync ...

[Rad_Schuhart]

The FW update (available for download within days) will fix this issue, we will take care of the airsoft switch and play the "boom" in sync ...

Great news! Now it would be great to have it in Ibu2 too and be able to update ourselves.

[Peregrine]

The FW update (available for download within days) will fix this issue, we will take care of the airsoft switch and play the "boom" in sync ...

Really? Excuse my skepticism. Will it be fixed exactly as I proposed? Or to rephrase the question, will sound and recoil servo initiate when the trigger signal is received (not earlier), and will the airsoft motor be stopped at that point? Can you provide any more details?

[theibuman]

Yes