DIY Atari 7800 stick guide?

[RawSteelUT]

Hey everyone!

 

I'm looking to put together an Atari 7800 stick (well, I wanna use it for my 130XE, but also for my 7800). I have, however, been having trouble finding a good, step-by-step guide for it, which is odd, since I've found a pretty good one for 2600 controller DIY. Anyone here know a link to a good step-by-step guide and what I'll need (aside from the obvious stick, buttons and button wires) to get this job done? Thanks for you help!

[Trebor]

Hopefully this helps:

2600/7800 pinouts:
 _________________
 \ o5 o4 o3 o2 o1/
  \ o9 o8 o7 o6 /
   \___________/
 
 pin #  2600 control     7800 control
   1    WHT- Up          WHT- Up
   2    BLU- Down        BLU- Down
   3    GRN- Left        GRN- Left
   4    BRN- Right       BRN- Right
   5    unused           RED- Button (R)ight (-)
   6    ORG- Button      ORG- Both buttons (+)
   7    unused (+5v)     unused (+5v)
   8    BLK- Ground(-)   BLK- Ground(-)
   9    unused           YLW- Button (L)eft  (-)
 
 
 2600 control (button)
 
 pin 6 ORG(+) --------------()------------BLK(-) pin 8
                       Button
 
 7800 control (buttons)
 
                                        /----------YLW(-) pin 9
                             Button L  /
                       /---------()---| YLW splits
                      /                \----///-----\
 pin 6 ORG(+) -------| ORG splits           620 ohm  |---BLK(-) pin 8
                      \                /----///-----/
                       \---------()---|     620 ohm
                            Button R   \RED splits
                                        \----------RED(-) pin 5

Source: http://atariage.com/7800/faq/index.html?SystemID=7800#cat2_9

[RawSteelUT]

OK, so does the ground for each button get their own 620ohm resistor, or are they sharing one between the two buttons? Also, that diagram says that pin 6 is both, but pin 5 is right. I'm assuming that's just for people who want to use both buttons in 2600 mode?

[alex_79]

OK, so does the ground for each button get their own 620ohm resistor, or are they sharing one between the two buttons?

2 resitors, one for each button.

 

Also, that diagram says that pin 6 is both, but pin 5 is right. I'm assuming that's just for people who want to use both buttons in 2600 mode?

No, if you don't connect pin 6 to both buttons, they won't work at all even in 7800 mode.

You must follow the schematic posted bu Trebor:

 

Left button between pin 6 and 9

Right button between pin 6 and 5

620 ohm resistor between pin 9 and 8

620 ohm resistor between pin 5 and 8

 

You can probably use 560 or 680 ohm resistors which are common values instead of 620 ohm

[RawSteelUT]

 

Left button between pin 6 and 9

Right button between pin 6 and 5
620 ohm resistor between pin 9 and 8
620 ohm resistor between pin 5 and 8

 

OK, so put each 620 ohm resistor in the ground wire for each of the buttons, and then mix the pin 6 wire into the wires for pin 5 and 9 each? Like this picture?

[alex_79]

like this:

 

This is the full joystick:

[RawSteelUT]

I'm not entirely sure I've got this right. I'm using western buttons/microswitches, so I wanna make absolutely sure. Pin 9 and 5 go into the ground port, with the wire from pin 8 mixing into those wires, and then pin 6 goes into the actual circuit port of the microswitch?

[alex_79]

What do you mean with "ground port" or "circuit port" of a switch?
In a 7800 controller, none of the pins of the fire buttons is directly connected to ground (which, on the Atari, is pin 8 of the joystick connector).

You need a simple "normally open" switch for this application. There are just two pins which are disconnected when the button is released and connected when it's pressed. If the microswitch you're using has 3 pins, two of them are labeled NO (normally open) and NC (normally closed), the third is the common pin. In this case, when the switch is released, the NC pin is connected to the common one while the NO is disconnected. When you press the switch, the NC contact is disonnected, while the NO is connected to the common one.
Just leave the NC pin unconnected and use the other two (it doesn't matter in which order!).

Connect pin 6 to one of those pins and pin 9 (for left button) or 5 (for right) to the other one.
Then connect one resistor between pin 8 and 9 and the other one between pin 8 and 5. All pins connected together by a wire are electrically the same point, so it doesn't matter if you connect the resistor directly in the plug, to the button pin or halfway to the wire connecting the two.

The three configurations below are electrically the same thing:

[edladdin]

In case it is helpful, but here is a collection of photos that show the actual wiring steps for the harness for one of our "Supreme" controllers, where there are two of each fire button. The numbers AND the wire colors shown correspond directly to the diagram posted by Trebor, so the white wire ties to the #1 pin and delivers the (+) side of the "Up" signal. Feel free to let me know if you have questions about any of this!

[RawSteelUT]

That's funny, I just posted now, but it didn't show up.

 

Anyway, I'm using this switch here for each of the buttons. Normally, the outer prong is where you put the ground. So in this case, I can use the outer and the NO pins in any order, and mix ground with the the fire button cables, each with their own resistor on their ground cable?

[Andromeda Stardust]

I know the official schematic called for 620 ohm resistors but Radio Shack does not sell this denomination. I used 560 ohm resistors in both of my sticks as well as my NES to 7800 conversion and they worked great!

 

Joysick use pin 8 GND for the common. The buttons use pin 6 FIRE for the common. Each button gets it's own resistor between ground and the normally open NO contact. The NO contacts are also connected to pins 5 and 9 respectively. What I did for my 7800 joystick was to wire both resistors in series by twisting the leads together. Then I solder one end to one button and the other end to the other button. Finally I tap a wire from pin 8 (also common connection on the joystick) and solder it between the resistors. The switches are close together, won't move around, and all other wires are insulated, so it was easier for me to solder the resistors directly to the microswitches instead of inline and deal with heat shrink, etc, so I only had wires running between the microswitch contact lugs and the 9-pin header.

 

Atari 7800 joysticks work on principal that the resistors pass a medium amount of current. With 2600 and one button 7800 games, pin 6 fire button has a weak pull up signal, about 10k ohms. When either button is pressed, pin six gets pulled low by the 620 ohm resistor.. With 7800 two button games, a strong pull up signal is provided by a transistor inside the 7800. This transistor pushes much more current than the 10k pull up resistor normally used. The buttons alternately connect pin six FIRE to pins 5 and 9 of the Atari. So the 7800 reads the button presses on pin 5 and 9 in two button mode, signal high indicating a button press rather than low. A protection circuit also exists to disable the transistor that drives pin 6 in the event that a standard CX40 is used, shunting the pin 6 connection by pulling it low to ground. This way the transistor does not dump excessive current to ground and otherwise burn out, if using a non 7800 controller.

[RawSteelUT]

OK, so the joystick directions are how you'd normally attach them to the microswitches (with the active pin on the NO prong and ground on the outer prong, then for the buttons, you put the common 6 pin on the NO prong of both fire buttons' microswitches, then link the ground and wire for pins 5 and 9 each, each getting their own 620ohm resistor between the ground and the main wire, in the outer prong? Am I understanding this right?

 

And yeah, I realize my diagram isn't exactly great. Just short-handing it so as to try and make sense!

 

[Jinks]

If you make 90 degree lines on your diagram like all diagrams are it would look perfect.

[RawSteelUT]

Well, at least I've got the way it needs to be wired. Now I just have two more questions.

The resistors seem to have some distinctive markings. Does it matter which side of the resistor is on the active wire versus which one is on ground?

 

Also, is there any place I can find a good diagram with screwholes for the layout? I looked at Slagcoin, and theirs doesn't have screwholes for the mounting plate. I'm using an IL Eurojoystick, if that helps.

[bikeguychicago]

The mounting plate pattern is usually provided by the manufacturer of the joystick you purchase. If you buy the sticks from places like Paradise Arcade Shop or Groovy Game Gear, you can usually download a PDF of the joystick plate/mounting holes ahead of time.

[NinjaWarrior]

How about for the Paddles

 

What Pin on the VCS Contoller controls the Paddle Movement?

[Andromeda Stardust]

How about for the Paddles

 

What Pin on the VCS Contoller controls the Paddle Movement?

Paddles use Pin 5 and 9. A 1 Meg ohm pot connects between the wheel and VCC (pin #7). left paddle uses joy right and right paddle uses joy left for the triggers. Backwards, I know. The paddle Fire buttons connects to ground on the common. I have personally found that 1 Meg ohm pots tend to be extremely twitchy for my taste. Most games only use a small fraction of the full range so I used 470k ohm pots in my VCS arcade controller build.

 

My Atari VCS joystick has a DPDT switch on pins 5 and 9 to alternately use Paddle or enable 7800 mode. If you should build homebrew paddles into your VCS joystick, it is recommended to use a switch to disconnect the paddle pots because a few games (including all 7800 titles that expect a 2-button controller, as well as homebrews which read Genesis C button) may not function properly with the paddles connected. Pins 5 and 9 on the VCS are normally low unless a controller is used that utilises these inputs. Most joystick enabled VCS games ignore them but a few misbehave when using a Genny controller or a joystick with built in paddles.

[Andromeda Stardust]

OK, so the joystick directions are how you'd normally attach them to the microswitches (with the active pin on the NO prong and ground on the outer prong, then for the buttons, you put the common 6 pin on the NO prong of both fire buttons' microswitches, then link the ground and wire for pins 5 and 9 each, each getting their own 620ohm resistor between the ground and the main wire, in the outer prong? Am I understanding this right?

 

And yeah, I realize my diagram isn't exactly great. Just short-handing it so as to try and make sense!

 

likethis.png

Looking good.

 

The resistors seem to have some distinctive markings. Does it matter which side of the resistor is on the active wire versus which one is on ground?

Orientation of resistors does not matter. For two lead passive components, only diodes and electrolytic caps you need to pay attention to orientation.

[RawSteelUT]

Well, I put the thing together, but I seem to be having issues. It works fine in 2600 mode, but when I try to play 7800 Xevious, both buttons fire both the bullets and the bomb. Is that normal for Xevious 7800? I've played it on emulator and they were on distinct fire buttons (though the bomb was on left and the bullets were on right), but the instructions suggest it's a one-button game. I'm looking at other games that are more obviously multi-button, but in the meantime, is that normal for Xevious 7800?

 

EDIT: It seems Xevious is single-button on RetroArch, and I now know that BizHawk isn't to be trusted for Atari 7800. Now I need another game to check it out. I'm looking at Ikari Warriors, but are there any other games I should look at to try the multi-button feature?

Edited August 13, 2016 by RawSteelUT

[Trebor]

Well, I put the thing together, but I seem to be having issues. It works fine in 2600 mode, but when I try to play 7800 Xevious, both buttons fire both the bullets and the bomb. Is that normal for Xevious 7800? I've played it on emulator and they were on distinct fire buttons (though the bomb was on left and the bullets were on right), but the instructions suggest it's a one-button game. I'm looking at other games that are more obviously multi-button, but in the meantime, is that normal for Xevious 7800?

 

Check your Difficulty Switch settings on the console.

[RawSteelUT]

 

Check your Difficulty Switch settings on the console.

 

You are fucking BEAUTIFUL, Trebor!

 

WIth the switches both on left, the left button fires blaster rounds while the right fires the bombs. It's alive! Works like a dream!

 

Thank you ALL for helping me out on building this bad boy. It's so hard to find good Atari 7800 controllers, so being able to make one is a HUGE deal. Seriously, everyone on this forum has been such a great help!

 

I'll be sure to post a screenshot later in the day. But seriously guys, thank you all for your help! Love you all!

[RawSteelUT]

And here she is, my baby!

 

For all the headaches wiring gave me, I had a couple of lucky breaks in sourcing the case. I live close to a cigar shop, so I was able to source a humidor for around $40. While I had to get the bits (particularly the hole saws for the shaft and buttons), my brother had a drill and was willing to drill the holes for me. He did a pretty good job, methinks.

For the stick and buttons, I went with an IL Eurojoystick, paired with IL concave push-buttons (short stem) with Cherry micro-switches. It's an absolute pleasure to use, and I'm just over the moon with joy that I have such an awesome stick! All that's left is to put a lock of some sort at the front to keep any kids that I may have over from getting to the cables, and sourcing an Atari 7800 sticker for decoration.

 

Might do an NES stick one day, though I imagine that takes a lot more work. I'd try for a 5200 stick, but I don't think I'll ever find a humidor that big. For now, though, I'm just going to enjoy my new 7800 stick.

 

Once again, thank you ALL for having been SO helpful!

[Andromeda Stardust]

And here she is, my baby!

 

For all the headaches wiring gave me, I had a couple of lucky breaks in sourcing the case. I live close to a cigar shop, so I was able to source a humidor for around $40. While I had to get the bits (particularly the hole saws for the shaft and buttons), my brother had a drill and was willing to drill the holes for me. He did a pretty good job, methinks.

The craftsmanship on that box is gorgeous. Honestly as a non-smoker, I have not thought to use Humidors. Ripping perfectly straight cuts can be done using a circular saw and and an edge guide, but it is a PITA. Maybe I could check thrift stores / antique shops for wooden cigar or jewelery boxes. I need to make a "starpath" 5-button controller for playing Space Rocks and Star Castle.

 

A professionally made stained finished wood box with beveled edges and a lid that opens easily exposing the internals would be perfect for future projects. A 1/8" bit as a guide and a 1 1/8" spade bit are all you need, and a 1/4" piece of scrap clamped over the top to prevent splintering.

 

Most pros recommend a drill press and a Fresnel bit, but you can't use a Fresnel bit with a handheld drill because it can and will cut sideways, resulting in a wider, uneven hole.

[RawSteelUT]

I might give drilling my own holes on a stick a go. I've never had the steadiest hand in the world, so for this first project (and given how pricy the box was!), I wanted someone who was a bit more capable than I to do the work.

 

But yeah, cigar boxes are great for this sort of thing. Just make sure you get one that's big enough for your joystick. Having never seen an IL stick outside its cabinet before this, I was quite shocked at how much clearance it needed.

[Andromeda Stardust]

I might give drilling my own holes on a stick a go. I've never had the steadiest hand in the world, so for this first project (and given how pricy the box was!), I wanted someone who was a bit more capable than I to do the work.

 

But yeah, cigar boxes are great for this sort of thing. Just make sure you get one that's big enough for your joystick. Having never seen an IL stick outside its cabinet before this, I was quite shocked at how much clearance it needed.

Clamp a scrap of 1/4" plywood to the lid before you drill. This will help prevent slintering of the box lid. Also use a 1/8" starter hole to guide the spade.

 

Also don't use a triple blade speed bore. They are faster than a spade but tend to cause blow out. Forster bits are cleanest hole and perfect for drill press but as they can cut sideways, not recommended for free hand.

 

Happ buttons need around 2" clearance beneath the hole but it depends on wood thickness. Happ sticks need 3" clearance.

 

Sanwa sticks and buttons are lower profile than Happ but not recommended for more than 1/4" thick enclosure. If your control panel is thicker than 1/4" you will need to route out the wood a bit so the sticks sit higher.

 

Sanwa/Simitsu low profile buttons are not standard 9/8" or 28mm hole size. I have only ever used Happ/IL style plungers for buttons so cannot comment on the buttons.

 

Japanese hardware is generally low profile and often used in "fight sticks" commonly sit no higher than 2 inches off the table.