home made controller using variable resistors

[cmallett812]

I built a 2600/7800 arcade controller a few weeks ago, and now I'd like to try my hand at building one for the 5200.

I am seeing however, that this is a whole different beast... digital to analog and all that...

I've seen how some people went about doing it, but the ones that caught my attention are the ones that use variable resistors... from what I've seen, it looks like you can really dial it in that way, with the added benefit of being able to use the horizontal pot with some games like a paddle.

The problem is that although I am handy with a soldering iron, I am not an electronics engineer by a long shot.  I am learning, but I have a good way to go.

 

So my question is, has anyone built this circuit using pots, rather than fixed resistors?

But I guess the more important question is, would any of you who has done this be willing to help?

Even a simple drawing of how you wired everything would be fantastic, because I am stumped on this one.

Any help would be very much appreciated.

 

Thanks!

 

PS:  I have a great schematic of a circuit using fixed resistors and transistors... but I don't have enough background in electronics to use that drawing with variable resistors...  I am a total newb... lol

 

 

[8bitAndy]

I don't have a schematic, but maybe this will help.

Atari 5200 FAQ -- 5200 Controller Pinout (atarihq.com)

The controllers work by putting resistance between pin 9 (Pot common which is around +5v plus or minus a volt) and pin 10 for horizontal and pin 11 for vertical.

 

The range of resistance is from about 100 ohms to 500K ohms, with 250K being about the middle of the axis. 

 

You will want to replace some of your fixed resistance with a potentiometer, which has variable resistance.

 

If the middle of the axis is 250k fixed resistance, you could change it to 200k fixed, plus a 100k pot. The 100k pot will be 50k in the middle.

This would make your controller midpoint adjustable between 200k and 300k.

 

You may want a pot with more than 100k resistance - if you can't find one you can also add capacitance to the circuit to reduce the amount of resistance you need. This is due to the way the Atari measures the resistance:

Homemade Atari 5200 Analog Controller – Dr. Scott M. Baker (smbaker.com)

 

If you have a AtariMax cart you can download Pete's Test Cart, which will show you the output of the joystick as a dot on the screen which makes it easier to test the circuit.

 

 

[cmallett812]

Ok, awesome! Thank you very much. 

I really appreciate the help, and that helps a lot. 

[bohoki]

when i made my altoid tin controller its just 4 push buttons  up button is connected to 9,11 down button is connected to 11,15  left is 9,10 right is 10,15

you connect a resistor between 9 and 11 for uppy downy and 9 and 10 for lefty righty

[Danjovic]

Hey @cmallett812, the thread below should be useful for you. 

 

[cmallett812]

Thanks you, everyone!  All of this info is very helpful!  

[cmallett812]

I got it built and working!

 

Almost every game I've thrown at it works perfectly after centering the dot with Pete's Test Cartridge, though some games require making adjustments to the pots even after centering everything.  For instance, Ms. Pac-Man & Galaxian require adjustments to the pots every time...  Jr. Pac-Man however, I can't get to work no matter how much I adjust the pots.  And of course, the analog only games don't work (next project, maybe?  lol).  

 

So, overall, I'm 99% happy with it.  After everything I read, I knew going in that there would be a few problem games.

 

So, big thank you to everyone that chimed in with help.  It is very much appreciated!