8bitAndy

The digital pot can produce all the controller positions that the old analog pots can.

I'm not selling anything, this will be a DIY project.

Just in parts, it was probably $50-$60. I only planned to build two or three so I went with parts that I know and would make it easier for me to build. Someone with more experience with PCBs and microcontrollers could probably reduce the cost by $20 by redesigning the PCB.

I was thinking of a hot-wire rig to clear out the shell. Something simple with a nichrome wire and DC supply. It would need to be nimble. I used a Dremel with a cutting wheel and cleaned up some with a razor but it took too long and could have easily messed up the shell. As for the start/pause/reset, I had room on the PCB and thought they could be test points or the board could be reused in another project.

Thanks for the feedback. I plan on publishing the STL and KiCad files for anyone to make as a DIY project. The built takes a while because the original controller has to be carved out to make room for everything. There is some wiring and soldering involved with the buttons and PCB components. I'm still working on the extra features of the software. I'm planning on: A way to set the X and Y limits and center using something like Pete's Test Cart. No adjustment of the POKEY pot needed. A more "digital" response curve to the joystick, so a small movement makes a full directional change. I'm also going to make a pure USB version to use with 5200 emulators or other 80's consoles with keypads.

This is a project I've been working on for a couple of years on and off. It's a full upgrade to the internal parts of the CX52 controller with no changes to the outside appearance - Joystick is analog self-centering Keypad has push button switches Fire buttons have micro switches All rubber buttons and the controller cable were reused. It uses a microcontroller to translate the joystick to the 5200 resistance levels and can be set to different joystick modes based on keypad + fire button combos with a piezo buzzer for feedback. It took a while to get everything to fit, but the end result looks just like the original.

The games I played the most -Realsports Baseball Montezuma's Revenge Mario Bros Super Cobra

Do you mean the controller adjustment pot? I don't know about a chroma adjustment pot. In any case, you could try replacing it with a fixed resistor or a fixed resistor plus a lower resistance pot.

The controllers are old school, so you can cross wires to test. Be careful, you could break something if you cross the wrong wires. The keypad and the start, pause, reset buttons are triggered by crossing a row and a column wire. See the matrix table on your link. For instance, Start would be Pin 7 (row for 1,2,3 and Start) crossed to Pin 4 (column for Start, Pause and Reset) The fire buttons are crossed to ground. The bottom fire button is pin 13 to pin 15. The top fire button is pin 14 to pin 15. There is voltage on pins 9 and 12, don't cross anything with these.

I see that the 5200 keypad is broken into 4 rows and 4 columns. An oscilloscope shows each row being brough high to about 5v in turn, with each row being brought high 0.5ms apart, with all four rows being scanned every 2ms. This works out to the keypad being scanned 500 times a second. This is surprisingly fast! Does this seem accurate? Also, how do developers read the keypad? Is time between key scans something that the developer controls or is responsible for? Thanks

I can't find the Spin-Cart for sale anywhere. Are there any other collections of Vectrex roms that support a spinner controller?

It's great that you want to share your extensive knowledge of programming the 5200! I can't join the twitch stream but I'd be interested in watching on Youtube. Thanks!

The top left and top right buttons share a pin (#14), and the bottom left and bottom right buttons share a pin (#13). Many games use the two buttons for different functions. This looks like a cool project. Atari 5200 FAQ -- 5200 Controller Pinout (atarihq.com)

Yes, use the arms that are connected - the controller works by varying the resistance between the two wires attached to each pot. You can use the resistance measurement on your multimeter by selecting the Ohm setting that looks like a horseshoe. Measure the resistance between the tabs connected to the red and black wires. The top pot should read about 250K ohms when it's arm is pointed left. The bottom pot should read 250K ohms when it's arm is pointing down.

You can measure the resistance with a multimeter to get an idea of how bad they are. They should range from close to 0 ohm to 500Kohm, with about 250Kohm when the arm is in its centered position.

This is a must-buy for me as well.

I ended up taking a different direction and converted the TI keyboard to USB to use with the Mister so it looks totally stock. I decided to do it this way because creating a keyboard that fits the TI seems like a lot of work, and I would use a large wireless keyboard for any serious keyboarding anyway. The TI keyboard is fine for basic Mister stuff.

This looks great, lots of polish on the objects and effects. There is a twitter dev thread here: https://twitter.com/minsoftgames/status/1479564281809195012

Protector has a good demo mode that cycles between high scores, game play and instructions. Are there other games with a good demo mode?

I have some experience with bad controller pots and the AtariMax menu, but I've never worked on the console itself.

The pots in the controllers may be dirty, but that shouldn't cause the AtariMax menu to be totally unresponsive. Do you have the service manual? ATARI CX5200 Service Manual, revision Jun 83 (atarimania.com)

You can check to make sure your controllers are good with a multimeter - check the resistance between pins 9 and 10 and 9 and 11 of your controllers. You should see between 0 ohm and 500k ohm resistance as you move the joystick around its limits. You should have ~250 Kohm with the stick in the middle. Atari 5200 FAQ -- 5200 Controller Pinout (atarihq.com) It is totally normal and expected for the AtariMax cart to beep if you are using a controller that is too far out of spec.

Thank you for this. I haven't run your code yet, but one difference I see is that you are pulling a row low and scanning for low columns, while I am pushing a row high and scanning for high columns. I have seen code samples that pull a row low, and code the pushes a row high. Is there an advantage of one over the other? Also, are those current-limiting resistors between the Arduino pins and the TI keyboard harness? Are you using any pullup resistors or relying on the internal pullup on the Arduino?

Thank you for this. The Phantom Keys section illustrates the problem perfectly. The problem I'm seeing in my code is that typing "the" too quickly often inserts a "k", such as "thke". The keys must be momentarily pressed down at the same time. Maybe I need to adjust the scanning rate.

Hi, I have a TI keyboard but not a working computer. I'm writing a keyboard scanning routine using an Arduino so I can use the keyboard in another project. When I press and hold (for example) T, H and E, I will also get a K due to the way my scanning routine handles the keyboard matrix. Does this happen with a real TI-99 computer?