totm june 2019 Custom hardware / simpit repository. For people who take KSP a little too far.

[richfiles]

12 hours ago, c4ooo said:

don't have the tools to work with metal.

Here's a quick tip for anyone who does have wood power tools (like a table saw or circular saw), and need to cut metal, but don't have a proper metal cutting blade. Reverse your blade. If your rough cutting blade has those carbide "chunks" at the tips, then flipping the blade so it spins backwards will let you cut metal. It'll almost certainly ruin the blade, but I've cut through 1/16 inch steel without any trouble using that method. Actually a really unique use for an old dull blade. By reversing it, the blade can't "grab" into the metal and jam, since the angle of the blade pushes the metal out of the gaps between teeth. The the carbide "chunks" at the end will still cut on the back edge, and take the fine bites out of the metal, like a fine toothed metal blade would. Of course, if you can find a proper metal cutting blade, stick with it.
 

12 hours ago, c4ooo said:

Hmm, I too am wondering how to make labels for switches

As for panel nomenclature, You could consider going to a shop that does silkscreening and have them do reverse art on the back side of an acrylic or polycarbonate sheet. If the text is done by either an absence of ink, or a transparent one, and the background is opaque, you can even backlight the panels. That's pretty much how it was done for the Apollo instrument panels.

If you wanna keep it on the cheap side though, a quality label maker can do wonders. Another tip for those, trim the corners of your labels so they are rounded. Corners seem to peel up more easily than edges, and a rounded corner seems more resilient, and it kinda looks nice, I think.

[stibbons]

15 hours ago, Freshmeat said:

I think it was @stibbons used printed decals.

Not me. My panels are laser-etched acrylic. Lovely if you have access to the tools (a laser cutter or cnc mill), but not really feasible otherwise. I wouldn't even expect a commercial shop would be willing to replicate the way that I'm doing it.

Edited February 13, 2017 by stibbons

[richfiles]

https://www.youtube.com/watch?v=LwXZKIfvEkI

Enjoy the final results! I found some usable resistors and installed them onto the alphanumeric displays.That allowed me to drive the ROM at the full 5 volts and allowed the ROM to operate as designed.

The irony of me making such a compact diode ROM to code my characters for the units display, is it kinda brings me full circle, all the way back to page 6 of this thread. Page 6 was the very first time I had ever commented here! Turns out my off topic comment about diode logic is FINALLY on topic! LOL 

**EDIT**

https://www.youtube.com/watch?v=1Wlv3oyobcg
Well, I guess I DO have some pics after all!

 
I like batteries for scale reference... Everyone knows how big batteries are. Coins can be different sizes in different countries.
Have the best of both worlds... A coin cell battery for scale! 

I went ahead and built the small diode ROM to control the "Time to" event indicator. I only needed 4 characters, but for consistency, I also added the all segments test character, and a basic dash, just because. This particular diode ROM is VERY small. It only has to drive a single 7 segment LED after all. Character test function will be it's own line that attaches to all the ROMs that I'll install. That one line will activate every segment at once. 

 

Edited February 14, 2017 by richfiles

[richfiles]

Just sharing that I finally did it... I started my own thread for my build. Kerbal Instrument Panel: In-Desk Apollo Themed Hardware Controller doesn't have a whole lot of content yet. It's more of a preview at the moment, but since I seem to have had a huge burst of progress lately, I think it's time that I should put all build details there, and keep any posts here more restrained. Don't worry though! I ain't leaving! I'll still share any help I can offer to people with questions. I might still post SOME progress here from time to time, but It'll be lighter posts, more limited to milestones, and definitely not the huge build progress posts that I'm known for.

I do think keeping the repository lively is important, but it was time... a year and a half ago... I just kept putting it off. I won't delete any posts from this thread, as those posts have served to inspire a lot of discussion, however I will likely consolidate all the data I've posted here into the new thread over time, focusing on sections of the build. And of course, all new build posts will be there.

[c4ooo]

I found a one axis joystick (pulled it from an rc helicopter controller)

However instead of using it directly, I think some hot glue will do nice in combining this 1 axis and this 2 axis joysticks into a single 3 axis joystick.

[richfiles]

9 hours ago, c4ooo said:

I found a one axis joystick (pulled it from an rc helicopter controller)

Personally, I'd consider the 1 axis stick as a viable potential throttle control. The Joystick will see extensive use, and in my experience, hot glue is good for securing loose wires down, but is certainly not something well suited for structural elements. The best cheap source of 3 axis joysticks I've found happens to be ebay. Just do a search for 3 axis joystick or 4 axis joystick, and you come up with a nice 3 axis joystick with a metal shaft, metal pivot ball, and a decent finger operable handle. The "4 axis" version has a tactile pushbutton on the top. I have not decided what I want my pushbutton to do... I've considered a secondary staging button, kill throttle, abort... I'm thinking kill throttle. I already have big glowy red and green "palm slammers" as my stage and abort buttons! 

The ebay joysticks are pretty affordable. About $17-25, depending on seller.

On a side note... It's been great knowing all you guys.
In a week and a half, I will probably disappear, not to be seen again for ages.
That's just what happens when a new Zelda game comes out! LOL 

Edited February 22, 2017 by richfiles

[c4ooo]

8 hours ago, richfiles said:

Personally, I'd consider the 1 axis stick as a viable potential throttle control. The Joystick will see extensive use, and in my experience, hot glue is good for securing loose wires down, but is certainly not something well suited for structural elements. The best cheap source of 3 axis joysticks I've found happens to be ebay. Just do a search for 3 axis joystick or 4 axis joystick, and you come up with a nice 3 axis joystick with a metal shaft, metal pivot ball, and a decent finger operable handle. The "4 axis" version has a tactile pushbutton on the top. I have not decided what I want my pushbutton to do... I've considered a secondary staging button, kill throttle, abort... I'm thinking kill throttle. I already have big glowy red and green "palm slammers" as my stage and abort buttons! 

The problem is - the 1 axis joystick seems to be somewhat inaccurate. It's fine for roll(rockets)/yaw(aeroplanes) (where its either center, left r right), but quite frankly i would want something more accurate for throttle control. Plus i already have a linear potentiometer that is well suited for throttle control. I do have to agree on the sturdiness of hot glue though - i think i could make a platform from wood that fits snugly around the knob of the 1-axis and that could have the 2-axis screwed onto it.

Although i may disagree, I appreciate all tips 

[richfiles]

How are you doing the third axis? Is it rotation of the entire stick and assembly? I guess you could try epoxy. I'd say that's a fair bit more durable than "hot snot". Building a platform sounds decent too. It gives the joystick assembly a solid base to mount to. It's really hard to see exactly how your 1 axis is set up in the pic, so it's hard to offer too many alternatives. There is one thing I could recommend. You could make your platform to mount the stick to, and drill out a hole in the center and simply mount it onto the shaft of a potentiometer. The potentiometer ought to keep the platform and stick base upright.

You could do other things to help stabilize it and keep mechanical stresses off the potentiometer too. Have you ever seen those furniture sliders? It's a little round or rectangular pad to put under furniture so it slides easily over the floor. If you mount one of those to the bottom of your platform (with a hole in the center for the potentiometer shaft to pass through, and then have it rest against the base where the potentiometer is mounted to (maybe with a felt pad to reduce noise), it will take all the forces pushing down on the assembly when you move the stick, and keep the base leveled as you move the stick around. A pair of screws or nails int he corners of the platform, and a pair of springs attached to those are all you need to keep it centered. You can easily create a deadzone in software to compensate for variation in repeatability at the home position.

Your 1 axis stick might be inaccurate due to a worn potentiometer. finding a replacement for it might solve the problem of repeatability and accuracy for it.

Of course, whatever materials you get have potential costs. Personally, I chose the easy route, so this is what I'm using.
Far simpler than trying to build something that will see constant motion, and trying to make it both durable and accurate.

The two joysticks are about $18 US off of ebay, come with rubber boots to keep dust from accumulating in the ball pivot (which is metal). They move forward and back, left and right, rotate clockwise and counter clockwise, and have a single clicky button on the top. Both of them use three 10K potentiometers for the three analog axes, and the button is just a switch.

The middle device is going to be my translation (RCS) controller. It's salvaged from a Fairchild Channel F game console from the mid 1970s. It's a digital controller, but it's actually a genuine 4 axis controller... up and down, left and right, in and out, and rotate CW and CCW. I got the controller from ebay, only cause I remembered the unique controller, thanks to my owning a Channel F as a kid. It's about as close as any controller ever got to the real translation controls on the Apollo and Shuttle vessels. I have no intention of modding the controller... I just want to make an opening where it can insert through, and then have a soft clamping mechanism to secure it. It'll plug in to a DIN-9 socket on the inside of the panel. That lets me preserve a vintage video game artifact, while still making use of it.

Also, preview of my next diode ROM module in the background! I'll post all that stuff in my own build thread. 

Edited February 22, 2017 by richfiles

[Ragequit]

I have mostly been lurking this thread for a while, but then i was really inspired by all the great projects and decided to try building my own control panel. I have got a lot of parts lying around

I started with thinking i would just mount some buttons and switches on a piece of MDF, but after doing a lot of research and looking at other projects it ended with me trying with a backlit and CNC-milled piece of acrylic. Im almost done with planning the first panel, but still not really happy with the grid and a bit unsure on how to do it in a good way while still being able to mill it.

The bars to the left and at the top are cutouts for motorized linear potentiometers (Flying faders). With two of them mounted on the board i get a two dimensional analog display. If you are docking, this can show you your relative position to the docking port. If you touch either of the potentiometer knobs it goes from display mode into input mode. If you then, for an example, position the knobs one tick to the left, your ship will use RCS until its relative position is one meter to the left of the docking port. 

The top right is a rotary switch to change what the display is showing and bottom right is to either automatically or manually set the scale on it. (The scale indicators light up individually). The input does different things depending on what mode you are in.

At the bottom you have a status led indicating that its trying to display something out of bounds, which in manual scaling mode basically tells you to decrease the scale.

 

Not sure if its easy to understand the concept of this display/input device. Im not going for the historically accurate or the most practical approach (Which is obvious looking at the picture). 

If anyone has any input on how the grid could be improved i would appreciate it!

Picture inside spoiler:

Spoiler

 

[richfiles]

Have you considered mounting a set of bars to the handles of the faders, to actually create crosshairs for the grid? That might look pretty sweet! 

LOVE the idea you're implementing with the faders!

Edited March 14, 2017 by richfiles

[Ragequit]

13 hours ago, richfiles said:

Have you considered mounting a set of bars to the handles of the faders, to actually create crosshairs for the grid? That might look pretty sweet! 

LOVE the idea you're implementing with the faders!

I actually have! I got some linear bearings and a piece on 3mm steel. Can upload the whole sketch later

 

Edit:

Got the complete sketch here. Not much more than the one before, but here it is

Spoiler

Red is size of (almost) everything behind the panel. Dark blue is the conceptual/planning layer. For an example, i used the planning layer to figure out the rotations of the rotary switch

Edited March 15, 2017 by Ragequit

[Pvt. KASA]

Helle there!

I am currently working on the FDAI and ive got a question:

Why are the Circles on the Ball concentric around the gimbal lock Points and Not the Poles?  http://www.collectspace.com/ubb/Forum14/HTML/000813.html

In KSP it is concentric about the Poles, right?

Also does somebody know what the diameter of the Ball is?

I already made the U-clamp and today I will be working on the central plate.

Thanks for your answers

Edited March 18, 2017 by Pvt. KASA

[richfiles]

The Gimbal of the Apollo craft were a three gimbal system, and there was a position where the gyros could position themselves where two axes of the sensor assembly were reading the same positions... Long story short, is if they let the craft orient itself into the area of the gimbal lock, the AGC could loose track of real attitude, and they'd have to bring the craft out of gimbal lock, and then recalibrate the AGC by triangulating on known celestial objects (typically stars). it was a major inconvenience, and dangerous if it happened near a burn, as entering the real attitude using star sighting took time.

Spoiler

Basically, if two gimbals line up on the same axis, and the vessel moves, the gimbal assembly stops rolling, cause the vessel is now can spin against the two lined axes, without spinning the sensor attached tot he system. It causes the control system to lose track of the real position of the vessel, since the gyroscope and the vessel fall out of alignment.

There are no concentric rings near the poles of the ball, cause the "poles" of the ball represented the gyro position that was at risk of gimbal lock. The vessel can actually be adjusted to represent other attitudes in relation to the ball. The ORDEAL system is what made the ball behave similar to KSP, where it is in reference to the horizon, vs tracking raw attitude. There might also be limitations due to the fact that the printing becomes more concentrated at the poles. My ball is set up to work more like the KSB ball is, with strict North, South, East, and West. The Apollo ball had numerical divisions, and they could take those values relative to the craft attitude and their place in their orbit or transfer.

More or less.

You only need the three internal axes in the ball to represent the 3 axes on the ball surface, but for the gyroscopes, it's critical to either avoid gimbal lock, or add a fourth gimbal a fourth gimbal only works because the fourth (outer) gimbal is powered, and forced to rotate 90° from the sensed position of the axis of the innermost gimbal. This physically prevents the lock condition, but makes for a more complex system. Kerbals "presumably" have a 4 gimbal system. Interestingly enough, the Mercury capsules used a four gimbal system. Apollo only used a three gimbal system for the weight savings (getting to the moon requires shaving every gram available, to reduce the fuel needed). The limitations were considered as part of the mission, and the computer, capsule, and astronauts together could always reorient the vessel and reset the attitude if required.

... Oh, 3D printing your pieces? I'm thinking of maybe buying a Tronix or an Anet soon.

Edited March 18, 2017 by richfiles

[Pvt. KASA]

Thank you for the explanation! I am still not sure if I should place the gimbal lock region around the poles (probably easier to integrate in KSP) or if I schould do it like apollo (bettet for Launch and landing...) Yeah I am 3D printing some stuff, the C-Clamp is made out of aluminium (aluminum where the non-metrics live ) with printed connectors inside. The Plate between the two Arms is made out of acrylic (because I had it l lying around in the right thickness). I also printed the Part that holds the inner axis Assembly (It is a Metal Tube with Ball bearings at the Ends where the inner axis goes trough) and the Part to connect the middle axis Motor to the C-clamp. I am also printing the parts to connect the hemispheres to the inner axis at the moment ( 1 1/2 h to Go and already 2 hours printing just for the First part ...) I think I will print the second one tomorrow.

Edited March 18, 2017 by Pvt. KASA

[richfiles]

For Kerbal Space Program, you won't ever suffer gimbal lock, as it's a condition only limited to the sensor/gyroscope system. Since the navball is driven (motorized), it'll never fall into lock, as it's not a passive system. The only reason to include a "gimbal lock" region on the ball, is if you wish to mimic it from the Apollo craft. It won't hold any meaning in terms of function though.

I'd have considered letting go of one of my security camera pan and rotate assemblies, with slip rings. Had I not bought a real FDAI, I'd have used them as my base structure.

[Pvt. KASA]

But if two of my gimbals align on the fdai and I move the "missing" axis, would that be possible? I think I didnt understand it because i dont know How this could work if i have 3 axis...

Nice Idea with the camera! Do they move fast enough? I am using the cheap Chinese 28byj-48 and they move at around 0,5 rpm (2s per revolution) max. I think that's enough for me but I will also add a light which indicates that the fdai isnt at the real position and needs time to catch up. I am also not sure yet if I'll add photo sensors for calibration. I think it would be easy to build and I have some here but I dont know if I would need them.

Maybe I'll have some pictures tomorrow.

KASA

Edited March 19, 2017 by Pvt. KASA

[richfiles]

That's a pretty slow FDAI, okay for big craft, but will forever be lagging for a moment, every single time you touch controls while maneuvering a small lander or capsule though. I have no idea if the stepper is capable of coarse steps, and if so, if it'd be possible to drive faster. In all honesty, if you wanna double the speed, get some gears. a 2:1 ratio between the stepper and what it's driving will double the speed. It might even be easier to build it too. Remember, one of the steppers, and ideally two of the steppers (for weight balance) need to be inside the ball, for it to work!


Here's an old pic from Page 7 that I did to kinda explain what's going on inside a navball, physically.

If you wanna use gears, then instead of having the motors directly drive stuff, you have a gear on the motor drive a gear on the axis. The motor would then be slightly off to the side then. You CAN have the pitch motor be on the outside, if the motor is sticking off the end of the C mount, but then you have to have enough room for it to not hit anything, and it imbalances the ball. If you use steppers, then you need at least an index sensor. That can be as simple as a phototransistor and LED with a tab that passes between them once per revolution. When the ball powers up, it will have to spin every axis till it hits the sensor, so it knows where the ball is. If you are good with programming, you might be able to use a camera to "see" the ball position. You'd need something like a Raspberry Pi with the camera accessory and more software skills than I'll ever have to do that. I'd recommend just clicking on that link to page 7, since there was a discussion on ideas for home made navballs way back then. You might get ideas!

Good luck!

Almost forgot! As for the confusion on 3 vs 4 gimbal systems, and gimbal lock... Understand that there are no motors on the axes of a 3 gimbal gyroscope system. It just has sensors. There's one motor that spins the weighted wheel for the gyroscope, but the gyroscope tries to hold stable while the ship moves around it. As the ship maneuvers, the spinning wheel of the gyroscope stays in the same attitude, and the gimbals rotate to allow the sensors to detect the difference between the ship attitude, and the gyroscope attitude. If two of the gimbals align with each other, then you lose the ability to tell the two axes apart, cause the ship can move and the gimbals can move in pairs and the gyroscope stays still, and the system loses track of the relative difference in attitude.

All navballs are three gimbal motorized systems. A motor and sensor drives each separate axis of the ball to the exact location it needs to be... It's not free-spinning like the gyroscope gimbals. Every axis could line up perfectly, but since motors drive it, nothing can drift out of alignment, and you can't have two axes moving together when they shouldn't.

A 4 axis gyroscope gimbal system has one extra gimbal that is motorized. That motorized gimbal forces the opposite gimbal to lock to it (kinda-ish), preventing it from locking with any of the other axes.

It's literally the difference between a car, a shopping cart, and a bike... The cart (3 gimbal gyro) can roll wherever it pleases, if you let go of it on a hill (pretend the hill is your gimbal lock), you're gonna lose control of it. The car (3 gimbal motorized) is easily controlled, regardless of if you are on a flat or a hill, cause everything is controlled by the driver, accelerator, brakes, steering... Nothing is free-wheeling on a car, you are in complete control. A bike (4 gimbal gyro) can freewheel down a hill, but you still have manual steering to guide it so you don't lose control.

Edited March 20, 2017 by richfiles

[Pvt. KASA]

Thank you again gor the explanation!

Its already too Late to change it but on the real Apollo one, the rate meters at the edges could display 50 degrees/s max so I think Apollo was moving at that speed. If I think of a capsule spinnig at 0,5 rpm, that seems pretty fast if you are not in ksp. I'll make some pictures after school and try to get the contact rings done. I think i'll print a Round part with 2mm height and some rings around the centre to seperate the contact rings. In the places where there is no seperation i put in a thin sheet of copper Or aluminum. I know this explanation was horrible but If I'm finished I'll post some pictures.

[richfiles]

1 hour ago, Pvt. KASA said:

Its already too Late to change it but on the real Apollo one, the rate meters at the edges could display 50 degrees/s max so I think Apollo was moving at that speed.

That's fair. If humans were in a Kerbal capsule doing the tricks it could do, you'd have an omelette in your skull! Actually, the fact that you have the rate meters is good. Using the rate meters alone, it's possible to pull oneself out of a wild spin, with enough time, fuel, and concentration. It is the one thing my FDAI regrettably does not have. The temptation to just buy three thin edgewise meters has been... high... But my instrument panel has strict space limitations, and I just don't think I have room to even try it. 

I've considered making a set of rate meters as my only digital LED bar meter, using these tiny puppies: 

These are routinely available on ebay, and i've actually seen a part like this in person on a very high end bit of test equipment (it was a $14000 digital phase angle volt meter. That was such a fine grained LED bar graph!) They are available in red or green, and I'm 100% certain I COULD fit these in the limited space I have available. The only problem I have is the cost. These tiny LED bar graph displays are only 5 mm long, with just 5 segments, and I've only ever seen them come from Ukraine. Individually, they're quite cheap, but once you add up the cost of enough to line up, it adds up.

[Pvt. KASA]

Here is a picture of the C-clamp:

The white Thing in the upper right contains a Ball bearing and the bar holds pieces of spring Steel against the contact plate which I am working on now.

UPDATE: just finished etching the contact plate, looks nice, tomorrow I will add some rings between the copper rings to prevent the contacts from slipping off.

Edited March 21, 2017 by Pvt. KASA

[richfiles]

That looks good! If I may recommend, try to find something called a pogo pin. You'll need a few for the each electrical contact on the assembly you printed, and a few for the point on the c frame where it pivots in the back to provide for roll (looks like you have not printed that yet, or if there are mounts of some kind, they are not visible. For a slip ring, you want round tipped versions. Quick disclaimer, I know the guy that runs this business. He actually hosts my website, but he ships internationally, and specializes in hobbyist customers like us. I didn't even go to his site directly, I just saw it as one of the top few hits on a google search for "round tip pogo pin" and decided to click it since I knew it. Okay, so disclaimers out of the way, These things are awesome for contact with a slip ring style PC board, and you can get them from a variety of suppliers. I should warn you, that even on Apollo, there are two spring contacts per ring, to ensure a good connection. Unlike a linear bit of spring, pogo pins won't require a groove to track the ring correctly. They won't drift left or right, and it'll contact directly below the hole you 3D print for it. The spring inside pushes the pin into constant contact with the PC board ring.

Internally, they work like this:

Spoiler

[richfiles]

You'll need to make a disc that that long shaft attaches to on both ends. You'll actually need to split the shaft so you can have one cross though sideways in the middle. Both shafts, the end attached to the motor, and the one attached to your bearing housing, will be firmly secured to the disc. That mechanism will rotate the disc then, in relation to your image, vertically. 

The slip rings on the top bearing housing will then feed wired into the edge of the disc, at the top, and those wires will then feed to a controller for a motor inside the ball (and to any sensors in the ball, such as a home position sensor). The motor inside the ball needs to have a fat coming out both the front and rear, or you need to gear it to a shaft beside it. You'll wanna create bearing housings that hold that shaft 90° though the plate. The ball, which is split into two halves, will fit onto each of the ends of that shaft.

The only thing left for you to do then, is attach the entire c-frame onto one more slipping and motor in the back.

That provides 3 axes, and everything you need to make a 3D printed navball.

I highly recommend having home position sensors for each axis. You can very easily calibrate the ball in software every single time it makes a full spin then. You won't even need a very powerful controller to do it. In software, it's as simple as setting the real ball location value to whatever value conforms to the physical location of the tab that interrupts your photo interrupter.

Here's how someone did it as a speed readout for a lathe. For your 3D printed parts, you just need a simple tab sticking out, vs a slot, and that tab only needs to pass through a photo interruptor once per turn of the axis, to mark a "home" or index position every time it goes around. 

Spoiler

You have to accommodate the width of the tab and the sensor as well... Each direction will have a slightly different "home" position. Those motors are 4096 steps per revolution, so your tab will take up several steps in wdith, even if it'd very narrow, but the edges will always be very reliable points to calibrate off of. Say, if it's going clockwise, and the sensor is interrupted, maybe that means the ball's index is 12° before the axis is aligned for 0°, so it looks at the real ball position value, and seed it says 343°, it would then update that to 348°, and let the software eliminate the drift between real ball position and the value the game is sending.

Let's also say that in the other direction, the photo interrupter triggers 5° positive of 0°, so if the real ball position variable reads 355° moving counter clockwise, then the software would reset the real ball position to 5°. and let the code do it's thing and adjust the ball to then match the values sent over the data packet from KSP. You could have an error allowance, where, say it won't trigger calibration unless the ball is more than 4 steps + or - of the expected values. This would prevent small switching errors when the sensor sits at the edge of triggering and not triggering, to prevent the ball from misbehaving when idle at the home positions.

Hopefully that makes some sense.

Edited March 22, 2017 by richfiles
I have no idea why I couldn't get text entry after the spoiler in the pervious message, or merge the messages... Weird.

[Pvt. KASA]

I just finished the Slip ring:

maybe i will make a notch instead of a tab for calibration...

Edited March 22, 2017 by Pvt. KASA

[richfiles]

Actually, a little notch cut into the edge of the slip ring, with the photo interrupter on the edge of the slip ring would be perfect for that purpose! Good idea!

[Pvt. KASA]

I ran into some problem but I may have found a solution...

The Problem is:

a) it is very hard to get the plate perfectly 90* relative to the axis

b) I am not sure if the way I thought I will build the contacts will work. 

I added some epoxy glue I mixed too much and put it between the rings to prevent the springy contact from slipping of and put it together with tape but I can't get a good contact. I will try it again tomorrow but I am also thinking about using a tube on one side and putting a cable through and then transmit a signal over a single line and decoding it in the ball with a attiny85. Of course i would need a way to get the single line outside but that would be a lot easier than 4 lines. I could do it like this:

If you have any Idea how to do this let me know...

Edited March 23, 2017 by Pvt. KASA