Helicopter pedals improvements

While building another set of helicopter pedals, I’ve accidentally cracked the wall of the frame in its weakest spot while press-fitting a 300mm piece of aluminum tubing.

As the frame is quite a long print, requiring some noticeable amount of plastic, I felt the need to do something with this problem (which I have already tried to address a while ago by inclining the tubing slot to reduce its shrinkage). As the fit is quite tight (which is intended) depending on a printer (and temp used to print parts, which should be higher than usual for pedals, I use 225 degrees centigrade for regular PLA, at first, try printing a frame leg and fitting it on a piece of aluminum tubing, it should not break), and also tubing used (there’s a tubing that is 9,8mmx 19,8mm and there’s a tubing that is 10,0×20,0) it may become overly tight. In this case, one needs to sand it a bit, but if the available clearance is misjudged, the frame can crack. Of course, that’s what happened to me (again!) =)

So, here’s the fix, that hopefully will straighten things out:

I have added 10mm extra width to the back of the frame and removed the forward slot for aluminum tubing because of aesthetical reasons (I’ve never used it anyway, and to make it reliable I would have had to add a similar “thing” to the front of the frame, which would have looked kinda out of its place). Note that I have also added a little chamfer, hoping to reduce shrinkage on edges thus reducing chances of an overly tight fit.

I have also added a mod with rubber band holders removed. I have been testing the spring-loaded version for a while now, and it works perfectly (better than rubber bands) yet this is a very refined thing I like to improve gradually. Besides, one can still use it with rubber bands just fine, but note that the latest force-trim mode for a spring-loaded cyclic will only work with pedals with springs. That’s because pedals have to return to the same exact spot every time when released, what actually cannot be achieved with rubber bands.

I hope to be able to print the new frame until tomorrow and tell you guys how things worked.

All changes are already in the repo.

Important pedals upgrade

Here’s what has been done to the pedals:

  • adjusted electronics housing dimensions so screws will fit correctly
  • added nut sockets to the main frame part
  • redesigned magnet and SS495A Hall effect sensor mounts (IMPORTANT!)
  • changed inclination of apertures for a rectangular pipe in the main frame part to 40 degrees for easier fit of the pipe
  • the frame was lightened to reduce chances of warping during a long print
  • files renamed to fit the new naming scheme
  • everything published to GitHub

This is a very important upgrade! Along with mostly cosmetic stuff, it includes new HE sensor and magnet mounts, that are really game changers. New mounts work the same way as in cyclic or collective levers, and add A LOT of precision! It have been really noticeable when I spooled up the Dreamfoil 407 for a quick test ride. The heli felt unusually stable! As a nice bonus, these mounts noticeably simplify calibration and add some mechanical resistance to drops or accidental hits  (this happens to pedals from time to time as the unit usually lies under the table).

Download an upgraded version from GitHub:

 

Thoughts on sensitivity of controls

I have been testing new hardware more thoroughly and noticed, that different sims have very different controls sensitivity settings (and ways to adjust it).  More than that, some of the sims tend to react on even the slightest jitter from Hall effect sensors and ADC (which is really almost nonexistent), while others ignore it completely.  That means that often, there’s a need for per-sim or even per-aircraft setting.

Simchair MKIII cyclic and pedals are sensitive enough to emulate the control response of lightest and twitchiest helicopters out there. But what if you feel it is too sensitive for the particular helicopter model you want to fly? Or, maybe the sim you are flying in treats joystick sensitivity settings differently, or even doesn’t have proper controls settings at all? What if setting curves is not what you want, but your sim doesn’t have any linear sensitivity adjustment options?

Continue reading “Thoughts on sensitivity of controls”

A better resolution for cyclic and pedals

While experimenting with adjusting controls sensitivity for different sims, I have found an interesting thing: in fact, the ADS1115 is so precise its values can be used without filtering at a 15-bit resolution! It is rather impressive 32768 points per axis. I can’t say the difference is as huge as between 8 bit and 12, but it depends on the game. For example, while I  only felt a marginal difference in DCS and X-plane, it was very noticeable in Arma 3. That’s why  I added an ADS1115_RESOLUTION constant to the master controller sketch.

You can set ADS1115 resolution like that:

#define ADS1115_RESOLUTION 15 //from 12 to 15 bits

I am now curious if changing a connection scheme of an ADC to a differential one will give even better results!

You can download an updated .ino file from GitHub.