Off the Shelf Trackball Options

[Hetzen]

And the trackball wires
20221226_145314.jpg

Did you get any of the controls hooked to to USB for MiSTer at all?

In that last pic, the black splodge on the circuit board is to stop people working out what the chip is doing with logic probes. I looked into what that would mean a while back and unfortunately didn't save links to YouTube videos or remember what software they were using, but it involved scrapping off that black stuff and connecting those pins to an interface, that would read live what the chip was transmitting.

[Chris23235]

I really want to pick up a trackball to use with Mister and Mame. I am having a hard time finding one on the used market. So, would something like a Kensington trackball work well? https://www.kensington.com/p/products/e ... ackball-3/

I use the GRS Spinner Trackball combo with my MiSTer. It is connected via USB as a mouse and works for me in Centipede with 400% and Marble Madness with 1:4. With said settings in the core I am able to enter my initials in the High Score table of the games without a problem which is to me always an indicator that the settings are at least roughly similar to the arcade machine.

[GuilhermeC]

You will see the block where the trackball connector sits, it's for Ultimarc's own U-Trak Trackball. The connectors are labelled X1 X2 Y1 Y2 +5v and Ground. I'm just guessing, but I would expect X1 X2 is for left and right, while Y1 and Y1 are for Up and Down.

Yeah, this is pretty much it, old school PC mouse / trackball and the N64 analog stick module use the same principle, it's just a couple of incremental optical encoders (one for each axis) and a pair of detectors for each axis. You'll have a couple of LEDs on one side, a couple of phototransistors on the other side and the encoder wheel in the middle.

As the wheel rotates, it lights up and obscures the detectors, but the distance between them makes they get their flashes / pulses at slightly different times. By looking which detector / phase got the pulse first, you figure out the direction of motion, and by counting how many pulses you get in a time interval (for example: 16.6ms or 20ms for one frame in NTSC / PAL systems) you'll know how much movement you got.

This board will work fine with older "dumb" trackball modules, but newer ones may be have a built-in IC to translate those pulses into something else and have serial, I2C, SPI, CAN or USB communication. Newer modules may use the same kind of optical sensors used in modern PC optical mouse / trackball, with or without an IC "translating" the protocol used by the sensor.

[GuilhermeC]

I've had no luck with all the common arduino project out there that say they work with a spinner or track ball.

My guess is that most simple Arduino spinner projects are using a simpler circuit that just has a resistor and a potentiometer between VCC and GND with an ADC pin connected between them, it's great for making simple, cheap controllers, but those modules don't look like they're simple/dumb, the spinner may be using a rotary encoder instead of a potentiometer and the trackball module also seems to have it's own microcontroller, newer revisions also seem to be using the same kind of optical sensor as a modern PC mouse or trackball, instead of optical encoders attached to rollers for each axis. If the trackball module was "dumb", it would have at least 6 pins/wires (power, ground and two phases for each axis), like the N64 analog stick module.

I saw "arcade1up" on the trackball module and decided to search "arcade1up trackball"... quite a few hits with a few different revisions of the same looking module. Looks like they have an internal IC/uC on the module that already digitizes the movement and sends through serial TTL, I2C or USB depending on the revision, I wouldn't be surprised if the spinner module also has a built-in IC and the fact that you can read SDA, SCL, TX and RX on those boards also hint that way. There's even a module you can buy to connect those modules to a PC or your MiSTer through USB, just search for "arcade1up" or "GRS" or "thunderstick", those are the keywords I've seen most often associated with those modules.

[Hetzen]

Re-Couchcade, I spoke to the Thundersticks guys via email, and they said the only way to get it to work over USB was to swap out all the parts with, funnily enough, their own stuff. But at that time, MiSTer wouldn't combine controls from two interfaces, one for their spinners and two buttons? The other was needed to hook up the extra fire buttons. Maybe they've had a word with their China contacts to be able to update this, but doubt it and probably a lot to do with licensing.

My conclusion was, yes it is big, but it is comfortable to use on your lap on a chair. BUT, the three left hand buttons you want for Missile Command were too far apart to be comfortable over a period of play; I guess there's a reason they used those volcano buttons on the OG hardware. The On/Off switch and volume directional push switch wouldn't be used. And if I was going to the trouble of re-doing the internals, I'd want to fix the buttons, which would mean cutting out a new front panel and putting on new vinyl then adding the edge T-strip. So what am I paying for? A plastic box and a cushion. It all felt a bit Trigger and having the same broom for 20 years.