Adaptive Technology, Arduino, Electronics, Making Stuff

Using Digital Joysticks As Analog With The XBOX Adaptive Controller (XBOX AC)

A viewer recently asked about connecting a digital arcade joystick (ex. a Sanwa with the 5 pin Dupont type connector) to the X1 or X2 jacks on the XBOX Adaptive Controller.

What he was seeing was odd values — the XBOX AC would show “full left” and “full down” (or visa versa). This is because the X1 and X2 jacks require Analog input — in other words, potentiometers. (Or an equivalent.)

I provided him some technical details on why this is, and why it can’t be (easily) done with discrete resistors. I’m working on possible solutions. In the meantime, here’s the info. I hope it helps others.

I’ve been experimenting with the digital joystick for use with the XBOX AC X1/X2 analog ports. Due to the limitations of the joystick you have, I’m not sure if it will be possible.

The Technical Details:

The X1/X2 jacks on the XBOX AC are expecting analog (potentiometer) input. This means a resistance between VCC and X/Y and another resistance between X/Y and GND. In electronics, this is a voltage divider, which the XBOX AC uses to determine position. A simple On/Off will not work — it needs the proper values for both connections (VCC/GND), and both directions (X/Y).

The easiest solution is to use an analog joystick. One that has potentiometers (one for X, another for Y).

When you plug in the TRRS jack without the proper resistance values, the XBOX AC will see that as “all low” or “all high”. In other words, you’ll see the joystick go full upper-right, or full-lower-left, etc. That’s why you are seeing that strange behavior.

If you have the parts on hand, you can experiment with how this works. You would need a 10K potentiometer and a selection of resistors. In one of the photos I’ve attached, I use the potentiometer to control the X axis. 

In another photo, you can see two 4.7K resistors hard-wired to the jack. One is connected VCC to X, the other GND to X. This creates a voltage divider with equal values on each side. The result is that the “stick” appears centered.

To make a digital stick simulate analog, it should be possible to connect resistors in such a way that the XBOX AC thinks there is a potentiometer in the circuit. There would be three states for each axis (values are examples):

Centered X : GND — 4.7K — X — 4.7K — VCC

Negative X: GND — 10K — X — 0K — VCC

Positive X: GND — 0K — X — 10K — VCC

It’s more complicated, but possible. But — here is the problem with the 5 conductor SANWA type joystick: it uses a common ground for all four switches. In other words, all four aren’t completely independent. Resistance on one switch would affect the others, throwing them all off.

Normally, I would go one of two routes with this:

* Use a microcontroller (ex. Arduino) to convert the digital signals to pseudo analog and pass via the USB connector.

* Use a DAC (Digital to Analc og Converter) to convert digital signals to analog and pass via the X1/X2 connectors.

Both of those solutions require additional electronics skill and/or programming to accomplish. If you want to follow one of those paths, I can help you through it. But, it won’t be as simple as “wire up and go”. The easiest wiring would be to purchase an analog joystick.

3D Printing, Adaptive Technology, Arduino, Electronics, Making Stuff

XBOX ADAPTIVE CONTROLLER (XAC) WITH JoyCon Style Stick and ARDUINO

For those of you interested in using a JoyCon style replacement stick with Arduino (like I’ve done with the bigger “Playstation 2” style sticks), please take a look at the files on github.

3D Models (in OpenSCAD) and STLs can be found here:

https://github.com/nelsonii/joycon

Code for running the joystick can be found here:

https://github.com/nelsonii/XBOX-Adaptive-Controller/tree/master/JoyConStick_Converter_ForXBOXAC_v2D

A word of warning: The Joycon replacement sticks are more difficult to work with. They use small (0.5mm) carbon leads and require a connector and breakout board. I’ve yet to find an easily available breakout. Send me a note if you’re interesting in learning more.

Why The JoyCon Stick? A person I’m working with needed a lighter touch stick. The easily found “PS2” style sticks are too stiff. The stick works very well, but, boy, is it a pain to wire up.

3D Printing, Electronics, Making Stuff

More Bench Testing The Matter And Form Scanner

Or: Baby Yoda goes for a ride.

My brick solution was working fine, but I couldn’t see what the table motor was doing. So, I put the whole thing on its side.

I did confirm that the brass insert in the middle of the table is 1/4-20. So, I put in a short bolt, some Fun Tak (or clay) and a lightweight object to scan.

The table started to spin, but is now hanging up. Motor doesn’t seem to be doing much. Either a bad motor (not too horrible to replace) or a bad driver board (into the garbage we go). I’ll have to remove the table motor and see if that’s it.

3D Printing, Electronics, Making Stuff

Taking Apart A Matter and Form 3D Desktop Scanner

For all of you poor souls looking for how to take apart a Matter and Form Scanner, here are a slew of photos I took. My turntable was no longer turning, so I wanted to see if it can be fixed.

While it’s possible to replace the table and its three bearings without taking everything apart, don’t bother. There are three wide tabs. You might break them. And the bearings will fall out anyway.

While I certainly appreciate the look and thought put into the case, this thing is like a 4th year design project. Like “you must use 5 different methods for assembling the case” — I guess a couple of screws are too 20th Century.

Enough of rant.

Get your T8 Torx screwdriver ready. Everything is Torx and prying.

Take the three obvious screws out of the bottom. That’s the only simple part.

Take the two screws that are not so obvious , above the camera head area, above the Matter and Form logo. These screws will likely fall into the case. Don’t worry. You’re taking the whole case apart anyway.

Using a pry (I used a tool I have for removing 3D prints — it’s metal, thin, and flexible. Pry the black back case. Follow the photos. Easier to see than explain.

Once the black cover is off, you’ll need to free the bed from the back camera assembly. There are two silver screws on one side. Remove, along with the half gear (you’ll see), and one side is free. Carefully rotate to release the other side — see photos.

For the turntable itself, pry the completely meaningless plug out of the center. You’ll see a brass insert. I have not determined a use for that, except it looks like 1/4-20 AKA tripod mount. Maybe they use it during assembly.

Carefully remove the rubber mat. There’s some sticky near the center, but mine has been sitting long enough that the sticky is gone. It’s just six little rubber nubs which are press fit into the metal turntable.

Now, CAREFULLY and SLOWLY rotate the table by hand to align the fix holes with six screws down inside. Unscrew those. Again, don’t bother if they fall into the case, you’re going in there anyway. (A lot of cheapie screws aren’t even ferrous, so mag drivers don’t help. Use a bit of clay when re-assembling. You’ll thank me later.)

Now that those six turntable screws are out, you should be able to gently raise the white plastic, back to front. As you do so, you’ll be able to shift the black decorative pieces out the the way. At this point you will see why I called this a 4th year project — no tabs or screws, but nubs instead!

You’re pretty much home-free now. You’ll probably see some bearings popped out of their plastic holders. The plastic bearing holders are probably broken.