This is a brief description how to mod an CY-822A USB joystick controller into accepting analogue input. I’ve done this modification now with two of my PCBs and worked with both for an extended period of time without any problems. To achieve this two things have to be done – at your own risk!
sdl2-jstest detected 5 axes
The PCB comes with 5 analogue axes according to my Linux PC and sdl2-jstest and while I’m not sure where the 5th is located a tiny modification will allow us to use at least 4 of the axes.
Locate the central lane and simply scratch off the track with a sharp knife at the 3 indicated positions.
Locate the resistors R1 – R8 on the front that make up for 4 possible connections for analogue input with the use of potentiometers. There are 2 resistors with ~10k on the PCB that have to go. The 2 resistors hold 4 of the 5 axes perfectly still in the centre because the middle lane is bridged on the backside. This is the part where the conductor path has to be interrupted. Locate the central lane and simply scratch off the track with a sharp knife. Also clean all the holes of R1 to R8 so you can solder in some new pins for easier access. Use a multimeter to make sure that none of the 4 central soldering points are connected with each other any more. The upper and lower ones stay connected (Plus and GND).
The wire bridge at J1 makes the board boot in analogue mode
Next we want to remove the zero ohm resistor at J1 and add a wire bridge instead. Look for an resistor with a single black ring next to R2, remove it, and solder in the wire bridge next to R1. This is basically a jumper setting but with a bridge. I’ve no idea why the designer went with a zero ohm resistor and not with a bridge. My only guess is that this was cheaper for the assembly machines.
Anyway, this will make the board boot in analogue mode so we do not have to use a mode switch on power on every time. This serves two purposes: Axes are now read from input and actually send as joystick events on the USB wire while the former digital joystick connector (5 pins) is now mapped to Up/Down/Left/Right buttons – so no extra buttons are needed here any more (but can still be added, of course).
Any potentiometer should do – mine are 100k – 200k. YMMV.
Now it’s time to connect potentiometers as analogue inputs. This is pretty straight forward. Just make sure that the central connector goes to the centre of each axes. Change the upper with the lower pin if the direction is not as desired.
Please note that any axes that has no input attached will report _a lot_ of jitter making your game/app go nuts. This is what the former resistors at R1 and R2 were there for.
The last update has been a while. I focused my attention to the MFDs (Multi-function display). This part didn’t get much attention yet and I was caught between the difficult choice to learn yet another fancy framework, like Raylib, that would do OpenGL ES 2.0 without X11 on the Raspberry – or just throw the might of my CoffeeLake at it and go with ReactJS since most of the data was already available via NodeRED anyway. Also… ARWES is just so cool 🤩
I went with ReactJS and ARWES again, simply because I have some experience in this by know thanks to my Streaming Overlay I wrote with it. Hobbling it up to NodeRED was just a matter of installing SocketIO to transport the messages. It’s all a very hacky mess but it gets the job done.
Video demonstration of my simulated cockpit made from cardboard on a budget mainly used to play Elite Dangerous in early 2022. This is work in progress.
While seeking through the available data I noticed that I don’t get velocity values from Elite. That’s not so important in space but _kinda_ interesting for me in planetary flight to satisfy the flight sim gamer in me as well. I noticed tho that I do get timestamped latitude, longitude and altitude values so shouldn’t it be possible to “simply” calculate this, right? Right?
This was when I dived into the rabbit hole of calculating velocity and heading on planetary objects using a spherical coordinate system and while I didn’t nail it exactly how Elite does it the result is close enough. The game provides the required data to go crazy here – most important the radius of the current object. In _theory_ I could start writing some primitive AFS (Auto Flight System) routines now, which I’m totally going to explore at some point in the future just because 🤓
Checking my maths – yes, altitude is added to the mix so velocity is mostly correct as long as no rapid course changes are made
After spending way too much time with this and the Pythagorean theorem (Yes mum, a game made me do maths. MATHS! 🤯) I settled with some calculations and data for my current ship to the right and targeted ship data on the left. This is sort of tricky because many game events update different parts of the data so timestamps have to be kept in mind and a game specific parsing strategy is required. See the last part of the demonstration video to get an idea how this looks.
Improving situational awareness by putting the video feed of wingman / gunner on the central MFD.
Another point to tick off my list was getting the head tracking to work in Elite (again). Now this is very Linux PC specific so you may tune out on this paragraph. On Linux PC I’d usually compile Opentrack with the Wine Glue, patch in my appdata dir for Proton and hope that it’s still ABI compliant to Just work™. Alas recent Proton is sandboxed within pressure vessel and the usual approach of memory mapping is simply no longer working, if I got the gist of this right.
So my _current_ strategy is to download and drop the Windows build of Opentrack into the game folder and chain-load the EXE with the game where the Opentrack EXE would listen on UDP while my native Opentrack BIN would send via UDP. A task not made easy with Proton but it is possible. The following snippet may give you some pointers:
Why running Opentrack twice? The native build performs a lot better with my webcam and every frame really count here. Reading data via UDP is not much of a burden for Proton. This also saves me the trouble of fiddling with Wine Glue, a painful compile process nobody should endure involving installation of many many additional 32bit libraries. Hilarious but it works.
When you have a water cooled computer the last thing you want to see is a message from your CPU driver telling you that it forcefully clamps down power because this means your CPU is throttling down.
Refilling an AIO be quiet water cooling system
This may mean that there is not enough water in your cooler and the CPU starts to overheat. Time for maintenance and a refill!
What we need for this is an external power supply or the pump, a pipe, an adapter, and some sort of filter hopper and of course water for the refill.
The pump is powered by 12V and this model should not be undervolted. Seriously, this one will break when undervolted. 12V is basically what an Ikea LED lights strip power supply will provide. You can also use another PC power supply but this is what I have anyway for a fan providing fresh air for my office.
The hose I used for the pipe is a used DN9 RAUFILAM-E from REHAU that I found in the barn. It costs about ~1 EUR per meter but you can of course buy a “special” hose from your usual PC parts mafia for 10 EUR per meter.
Distilled water should be fine. You can also purchase whatever overpriced holy water you may prefer. I won’t care.
I spare you the details how to remove the water cooler, because I assume you assembled it before and if not there are plenty of other tutorials on the net.
This pump was completely dry after opening the lid with a screw driver. I prepared this contraption held in place with a wire attached to the chandelier. So don’t do this at home. Now I started the pump and added water to the pipe until the pipe was filled.
Now is the time to move and shake the radiator to get all the air out. Do not shake the pump! This takes some time. You’re done when no more bubbles appear.
Don’t forget the seal and screw in the lid while there is still water standing in the hole. Do not use force on the lid, because it breaks easily.
Make sure everything is clean and tidy (and dry) in the end because you don’t want water in your PC. This also helps to see any leaks that may spring. Don’t forget the heat sink compound later or this will be a very short adventure.
When done let the pump run for a little bit to see if any water leaks out.
When everything is assembled again make sure to run a load test and see if any leak springs.
And this is it. The system is able to hold 32°C again where it was hardly able to hold 80°C before.
And as usual, if you break your system you get to keep the pieces.
I like space and science fiction. Diving into epic stories set in some distant future amazes me since elementary school.
I’m also a gamer. And a tinkerer. It’s in the family.
I keep wondering: How can I improve the immersion of my games without going full VR?
DIY Headtracker for gaming (on Linux PC)
I used a triple screen set-up before. It consisted of different models in height and size. When one screen finally broke down I purchased 3 refurbished screens of the same brand and model. What a difference!
The kids love it too. Of course. Means less stick time for me. Anyway.
This is when I started to read about head tracking and went on a quest to get this working for the game X4. As a bonus on Linux PC, my preferred system also for gaming.
The thing is: “The” reference product for a headtracker is the TrackIR system. Price as of today: 220 EUR. Ouch! That’s like a cheap VR, right? And it’s Windows only. No thanks.
So I checked what’s in this thing. Apparently a cheap camera, some infra-red LED, and a filter allowing only infra-red waves. And software, of course.
Since this is for Linux I get to pick my poison for the software part, and I settled with Opentrack fast. Onwards to the hardware part. I abused my mobile phone for the testing, sending it’s Gyroscope data via wifi to my PC, and while it worked it also _sucked_. Both, phone and wifi I mean.
Head tracking is awesome. And I knew I want it. So I started prototyping. For this I went with a simple design that I eventually implemented on cardboard. It looks hilarious but it gets the job done.
The focus was on a long life cycle so I wouldn’t have to replace the rechargables in the middle of a session. To get this right I checked with the camera that I was going to use. See (video above), this is way to bright and by trying various resistors I could get this down to 33mA per LED and still get a decent detection rate with Opentrack.
Speaking about the camera. That’s nothing special. It’s a dead cheap 480p Logitech QuickCam Communicate STX that I got from a discounter a decade ago. It was so cheap it doesn’t even _have_ an infra-red filter that I’d have to remove first.
I used tape to attach the salvaged camera cover of a dead G20 controller. That’s a Wii Remote knock-off that does basically the same thing like a headtracker. Various other foils can be used for this as well, as long as they permit infra-red. The idea is to reduce or remove all other light waves but infra-red.
The trick is to also turn off auto exposure and fiddle with the contrast and sharpness until a decent frame rate and a clear infra-red wave source by the LED can be seen.
When I was satisfied with my meter readouts, and my highly professional scribbles, I started working on the prototype while streaming the whole process on the Discord channel of the awesome Fly Dangerous project. If you like racing with a space ship give it a shot.
The prototype is made of cardboard that doubles as isolation for the polarity. The rest is tape and hook-and-loop fastener to attach the headtracker to my headphones. No magic here. The whole contraption is powered by two 1.2V rechargeables. I opted for a micro switch and an additional LED as power indicator, that I dimmed down even more. I can after all not see infra-red so this seemed like a good idea to me. Spoiler: It is.
So how does it play? Over the next weeks I tried basically any game supporting head tracking that I could get my hands on. Please keep in mind that I usually play with lights off but started the studio lights for demo purposes. The tracker does still work just fine.
I quickly found out that each game needs it’s own profile for fine tuned settings. Good thing that Opentrack has me covered on this. First, my beloved X4 using Wine and the TrackIR protocol.
Sadly I came to the conclusion that my GPU is no longer up for the task and Wine would cost me too many frames. I switched Opentrack to emulate a joystick instead and mapped it to camera movements in the native X4 version. It’s not exactly the same but it’s okay-ish. I have an idea how to hack this properly into X4 using an extension and a UDP server but that’s a topic for another day.
Anyway, the same principle works with X Rebirth too, making me even happier. While dated it still has it’s charm and the verse still feels a lot more alive compared to X4. It’s also not taxing my GPU that much.
Now for something different. When Opentrack would list a “protocol” named FlightGear I became very curious. I installed this free and open source flight simulator and crashed my first Cessna into the ground minutes later. By now I’m confident that I can crash a Cessna just about anywhere. I’m not fond of flying in real-life but avionics sure are a fascinating topic.
This was the moment a Steam sale happened and I bagged various flight sims, Space Kerbal and House Of The Dying Sun. All with TrackIR support.
Little did I know what gem I bagged with House Of The Dying Sun by the way. Sadly it’s also very short but I enjoyed every minute of it and will probably play it again. The art, sound and music reminds me a lot of Battlestar Galactica. Easy win 😀
So yeah, this is my current gaming set-up. I built myself a head tracker for 5 EUR. On Linux PC.
I also may have fallen into the rabbit hole called “simpit”.
