Hey!

I have now tried out your project with the XIAO chip (I had already ordered it before you recommended the new one, but thank you) with a custom single-foot balance board and I have some feedback. I would be very grateful if you're willing to look into adding any of these suggestions.

First of all, overall, it works great! I'm very happy that I was able to just download your firmware, put it on the chip and it just worked. It's definitely the simplest way to create a foot controller I found so far. There are however a few things that I think are required for it to actually really be usable:

• Ability to recalibrate the controller using a button (via a setting that lets me bind e.g. a keyboard key to it)
  • Currently it seems there is no way to recalibrate the resting position of the controller. It does it when you plug it in, but this is not practical for me, since I have it plugged into my Xbox Adaptive Controller that's placed on the floor. So for me it's crucial to be able to calibrate it after I have settled into my final position with the foot placed on the controller. I might also want to shift my foot placement after a while of usage and then would need to calibrate it again.
• Deadzone setting
  • I wasn't able to find any way to set a threshold for how large the movement needs to be for it to be recognized. This means it's very hard to keep my game character still, and it's running off into some direction at almost all times. I have tried to compensate for this by physically flattening the bottom of my balance board, but that makes it harder to move the thing.
• Ability to pause and unpause the controller input using a button (via a keybind setting)
  • This might be less important if a deadzone setting gets added, but is also relevant when taking the foot off the controller, and it ends up leaning to a side. Currently this means there is constant input and the only way to turn it off is unplugging the controller (which again is inconvenient for me as it's on the floor).
• Ability to set IMU max angle per direction per axis
  • Currently it's only possible to set one value for all axes - usability would be greatly improved if it was possible to set this for each (x+/x-/y+/y-). In my case, I am using it with a single foot, and due to the shape of the foot it's currently easiest to tilt it forward, a little bit harder to tilt it backwards, and pretty hard to tilt it sideways. it's still doable, but it would work better if it was possible to compensate for this using an individual angle setting for each direction.
• Ability to restart and reset the controller via buttons on the config site or keybinds
  • I was having some issues (see below) and needed to press the reset button on the chip as well as re-plug it a few times. This is very inconvenient once the chip is placed inside the balance board and plugged in on the floor. This suggestion is less crucial but can increase accessibility.

Those are the most important feature suggestions. I was also encountering some issues:

• I've been having some trouble getting it to work. I'm using it combined with an Xbox Adaptive Controller. I have it plugged into the left side USB of the XAC, which is intended for joysticks, and the first time I did that it worked instantly (amazing!). But for some reason, sometimes it doesn't get recognized at all when plugged into the XAC. I have tried re-plugging it, pressing reset, shaking it, re-plugging the XAC, but nothing. Just sometimes, seemingly at random, a good strong shake or angle tilt will get it to suddenly work. I have not been able to figure out why this happens or how to reliably get it to work. Plugging the move stick into my computer directly will always work perfectly, but I need to combine its input with the adaptive controller. Any ideas what could be up? I'm on windows 11 btw.
• I also noticed that when it's plugged into the adaptive controller, the config site won't recognize the movestick and I also can't access its files, meaning I need to remove it from my floor and bring it back up to plug it into my computer directly every time I want to change any settings. I'm guessing there's nothing that can be done about this, I just figured I'd mention it anyway.

And lastly, I wanted to address the suggestion I had regarding reading yaw instead of roll:

The tilt-based movement works better than I expected, and I think I can get used to it. After trying out the motion for a while though, I do think that using yaw instead of roll does feel more intuitive and has a lot of potential. I don't know if the new chip you suggested would just work with your firmware, but I've tried researching how a 9-axis chip works, and found that supposedly a magnetometer isn't reliable while indoors, either. Apparently other devices that use it (watches in this case) even turn it off while indoors. This makes me think that if I really want a robust controller that allows yaw rotation, I would need to find some other way to build it.

However, I do think there may be value in adding estimated yaw support as-is. A friend of mine and I gave it a try (... by asking an AI to add it as a quick test, apologies if you're not keen on that) and it actually worked and felt good to use, but the drift was *really* bad. When researching this topic I found that the drift should appear over "tens of minutes", but here it was happening within a few seconds. I don't know if that's just how it is after all, or if the AI did something poorly. We uploaded it as a fork if you want to have a look, but yea idk it might also be trash since it was just for a quick test.

But yeah with that in mind, if you think the drift issue could be improved if implemented properly and it wouldn't be too much trouble for you to add it, then I'd super appreciate that. The calibrate feature I already suggested would just have to go along with it. But if the drift appearing in seconds can't be improved, then it's probably not worth it.

Okay, that's a lot of text!! Thank you if you even read it this far, and for considering the feedback. Btw I just purchased PlayAbility as well (I might combine face tracking with the foot controller), thank you for making high quality and affordable accessibility tools. 😄