Vipergear Force Sensor for TM Cougar - is it any good?

[sirrah]

Hi,

As many people here, I wish to revive and update my broken Cougar (gimbal broke). Fellow community member FZG_Immel very kindly told me he would donate the gimbal of his (FSSB updated) Cougar, but I'm afraid I can only wait until that one will also break, not to mention the free play of the original gimbal set.

 

I can't justify the high costs of FSSB, so I was looking for alternatives.

 

Can anyone give any feedback on VFS for the Cougar?

 

I can only find 1 review on their website and 1 YouTube video on the installation. Googled and searched ED's forums for more reviews without results.

 

Would this be a decent alternative for FSSB? It's still not cheap imo, so I wish there were some more user reviews.

[sirrah]

In case anyone else is curious, I received this PM:

Hi

For some reason I can’t post in the tread. I have the VFS installed in the cougar. And I’m very happy with the result. I had to learn how to fly again, because of the system. It’s very precise in the response. The installation was easy. I used the YouTube video and the manual. Now I need to figure out how to hard mount the cougar so it doesn’t move when I tries to pull 9 G’s

 

Regards

Christian

[Terry Dactil]

I also have an old Cougar joystick with a busted gimbal.

I have converted it to a rigid version in anticipation of the arrival of the F16.

 

 

I used BF350-3AA/1.5AA strain gauges which are available on eBay for less than $5 each.

 

 

Some scrap lengths of plastic water pipe and some 3D printing and the job is done.

Now all I need is the F16. :thumbup:

[sirrah]

That's awesome!

I'd sure like to see how you've build/assembled this in more detail.

 

What components did you use exactly and what did you 3D print?

Also, did you entirely replace the old Cougar PCB?

And did you connect your throttle directly to your pc with a usb mod?

 

Please let me (us) know :D

[Terry Dactil]

The strain gauges are almost a drop-in replacement for the original potentiometers.

They have only 3 connections; ground, 5v power, and an outpu, just like the original pots.

Some adjustment is required as the output is 0v to 3.5v with the no-load voltage (1.75v) set by an adjustment on the circuit board.

 

All the dimensions are quite arbitrary:

I just sat in my flight seat (an office chair) holding the joystick handle and measured the distance to the bottom of the seat to where I could put a mounting bracket.

 

Then I cut a suitable length of plastic water pipe to make the bendy bit to mount the strain gauges on.

I 3D printed 3 mounting components to suit. I had all the dimensions for the bit that connects to the handle from previous joystick extensions.

There are videos on the web showing how to use clear tape to accurately position the strain gauges while attaching them with instant glue. All pretty simple.

 

You should be able to use the circuit board from the Cougar base with only a re-calibration of the x and y axis.

My original board died, so I have to make a new circuit board.

 

I converted the throttle to USB a long time ago. This was eay as all the wiring from the buttons and potentiometers was available in the base to connect to Leo Bodnar's BU0836 USB interface.

Quick and dirtyas it was before I could make PCBs and 3D print things.

This is not possible with the Cougar joystick, as there are 18 buttons but only 5 wires coming out of the handle.

It turns out that the button status comes out as 3 bytes on an SPI bus where each bit represents the position of a button.

The tricky bit is combining all that with the x and y axis readings and sendig it all out via USB.

I'm using the USB descriptor from the Warthog as a template to save re-inventing the wheel. :)

I'm using a PIC 18F4550 chip for the prototype as it has extra ports useful for debugging.

The final version will use the smaller 18F2550 chip.

[sirrah]

I'm afraid this will be a bit above my head :(

 

Some adjustment is required as the output is 0v to 3.5v with the no-load voltage (1.75v) set by an adjustment on the circuit board.

already lost you here :P

 

Also, you wrote that I should be able to use the standard Cougar circuit board, but is this board fit with proper connections for the new force sensors? No soldering or messing with the original PCB required?

 

 

 

Even though I'm a little uncertain if I have enough skills to build this, it tickles me to try it. Nothing beats DIY/home made projects imo. Sure, sometimes you win, sometimes you lose, but at least everything is build with passion and is more or less unique!

Edited October 3, 2019 by sirrah

[Terry Dactil]

Also, you wrote that I should be able to use the standard Cougar circuit board, but is this board fit with proper connections for the new force sensors? No soldering or messing with the original PCB required?

Yes. They are standard connections. You will need to get the polarity correct, though.

 

Some adjustment is required as the output is 0v to 3.5v with the no-load voltage (1.75v) set by an adjustment on the circuit board.

already lost you here

An explanation might help:

The normal Cougar X & Y axis potentiometers have a wiping contact on a resistor.

One end of the resistor is grounded (0 v) and the other end is connected to 5 volts. This means the voltage on the wiping contact depends on its position on the resistance and will be somewhere between zero and 5 volts.. All very cheap and simple, but it wears out or gets dirty and then the output voltage is all over the place. This is why hall effect transistors are used now: no moving contacts to wear out.

 

The strain gauge, however, is just a gadget whose resistance varies a tiny amount when it bends and changes length a minuscule amount. This is not directly usable as an output and needs to be amplifies (more than 100 times or so?) before it can be used. For some reason the amplifier used here can only output 3.5v maximum, and so its neutral point is adjusted to be halfway at 1.75 volts.

The output can then be scaled and calibrated with software. I use Leo Bodnar's DIView which is free.

 

 

Hope this helps.

Edited October 3, 2019 by Terry Dactil

[diskball]

@Terry DactilPlease please please can you share your stl files or design files for the Force sensitive assembly you have for the cougar stick?

 

thanks in advance!

[Terry Dactil]

OK. Here they are

.Rigid joystick STL files.zip

 

(If you need to make modifications and use Fusion360 I can probably find those files too).

[diskball]

On 4/22/2021 at 3:16 PM, Terry Dactil said:

OK. Here they are

.Rigid joystick STL files.zip

 

(If you need to make modifications and use Fusion360 I can probably find those files too).

Thanks a lot dude! that's great!
If you can send me the Fusion 360 files will be totally awesome as well, as I will need to tweak them a bit.

 

Cheers

 

[Steel Jaw]

I have that mod and it worked great while my Cougar lived (TQS broke).

[Terry Dactil]

Quote

If you can send me the Fusion 360 files will be totally awesome as well, as I will need to tweak them a bit.

Rigid joystick.f3d

You should be able to extract individual components from this assembly file.

If not, let me know and I can did out the individual flies.

[diskball]

Thanks a lot!