Atari 2600 Rapid fire circuit?

[27ace27]

does anybody have a circuit schematic for an atari 2600 rapid fire type thing?

[imac4567]

Couldn't you just make it where you flip a switch and it closes the circuit to the button, therefore making rapid fire

[27ace27]

Couldn't you just make it where you flip a switch and it closes the circuit to the button, therefore making rapid fire

 

no, because then it would just be one fire.

[imac4567]

True, I will keep thinking and searching for other ideas.

Edited May 26, 2009 by imac4567

[27ace27]

True, I will keep thinking and searching for other ideas.

 

gracias!

[nathanallan]

found something may be useful:

http://nfggames.com/forum2/index.php?topic=3567.0

[27ace27]

found something may be useful:

<a href="http://nfggames.com/forum2/index.php?topic=3567.0" target="_blank" rel="nofollow">http://nfggames.com/forum2/index.php?topic=3567.0</a>

 

yeah, I saw that, but that's for jaguar tho, right?

[BigO]

It wouldn't be too difficult to build such a circuit. It would just be something that turns on and off, known in digtal lingo as an astable or free running multivibrator. There's any number of ways to implement that circuit.

 

One challenge is that there is no +5v connection to the joystick to run the circuitry.

You could solve that problem by replacing the cable on the joystick or placing the circuit external to the joystick (this choice doesn't sound all that appealing).

 

Depending on how strongly the 4 directional lines are pulled up, you might be able to do something tricky with diodes to steal a little bit of power from those lines. (Note: This is theoretical. I have not looked into or tested this to any degree whatsoever so it may not be possible within the design parameters of the 2600 hardware.)

[27ace27]

It wouldn't be too difficult to build such a circuit. It would just be something that turns on and off, known in digtal lingo as an astable or free running multivibrator. There's any number of ways to implement that circuit.

 

One challenge is that there is no +5v connection to the joystick to run the circuitry.

You could solve that problem by replacing the cable on the joystick or placing the circuit external to the joystick (this choice doesn't sound all that appealing).

 

Depending on how strongly the 4 directional lines are pulled up, you might be able to do something tricky with diodes to steal a little bit of power from those lines. (Note: This is theoretical. I have not looked into or tested this to any degree whatsoever so it may not be possible within the design parameters of the 2600 hardware.)

 

actually, there is voltage on all of the other pins beside ground. enough to light an LED (that makes it easier for a lighted joystick http://www.atariage.com/forums/index.php?s...144606&hl=)

Edited May 26, 2009 by 27ace27

[BigO]

It wouldn't be too difficult to build such a circuit. It would just be something that turns on and off, known in digtal lingo as an astable or free running multivibrator. There's any number of ways to implement that circuit.

 

One challenge is that there is no +5v connection to the joystick to run the circuitry.

You could solve that problem by replacing the cable on the joystick or placing the circuit external to the joystick (this choice doesn't sound all that appealing).

 

Depending on how strongly the 4 directional lines are pulled up, you might be able to do something tricky with diodes to steal a little bit of power from those lines. (Note: This is theoretical. I have not looked into or tested this to any degree whatsoever so it may not be possible within the design parameters of the 2600 hardware.)

 

actually, there is voltage on all of the other pins beside ground. enough to light an LED (that makes it easier for a lighted joystick http://www.atariage.com/forums/index.php?s...144606&hl=)

 

Okay. So the corresponding LED to extinguishes when you move the joystick in any direction? And hooking up the LED doesn't load the line down to the point that it's recognized by the console as the line being activated (pulled to ground)? Good to know.

 

Sounds like they're pulled up fairly strongly and should be able to supply power for a small circuit mounted internal to the joystick. You'd need to pick the power off of at least two of the lines that are in opposite directions (i.e. up+down or left+right). I'd probably pull it from all 4 directional lines. You'll also have something less than 5 volts to work with after the power feeds through the isolation diodes. Probably should expect to have around 4.4 volts to power the circuit with.

Edited May 28, 2009 by BigO

[BigO]

...

Edited May 28, 2009 by BigO

[cwilkson]

You can use a 74hc14 hex inverter chip to do this. Connect a 100k resistor between pins 1 and 2. Connect a capacitor from pin 1 to ground. Pin 2 will give you a square wave. It's best to buffer it with another inverter though. So connect pin 2 to pin 3. The buffered output would be on pin 4. Connect that to pin 6 of the joystick port. You can power the circuit from the port as well. The 2600 has VCC (+5V) going out on pin 7 of the joystick ports. Pin 8 is ground. Pin 6 is the joystick fire button input.

 

The firing rate is proportional to the product of R and C. Try 1uF and 100k Ohm values to start. I don't have a 74HC14 handy, so I'm completely guessing the values for R and C. This should be slow enough for you to see the result. Reduce the values to speed it up, increase them to slow it down.

[27ace27]

You can use a 74hc14 hex inverter chip to do this. Connect a 100k resistor between pins 1 and 2. Connect a capacitor from pin 1 to ground. Pin 2 will give you a square wave. It's best to buffer it with another inverter though. So connect pin 2 to pin 3. The buffered output would be on pin 4. Connect that to pin 6 of the joystick port. You can power the circuit from the port as well. The 2600 has VCC (+5V) going out on pin 7 of the joystick ports. Pin 8 is ground. Pin 6 is the joystick fire button input.

 

The firing rate is proportional to the product of R and C. Try 1uF and 100k Ohm values to start. I don't have a 74HC14 handy, so I'm completely guessing the values for R and C. This should be slow enough for you to see the result. Reduce the values to speed it up, increase them to slow it down.

 

ummmmmmmmmmmmmmmmmm... schematic?

[cwilkson]

ummmmmmmmmmmmmmmmmm... schematic?

Yeah, I know. But I don't have the tools to prettify something for you right now. And I'm not about to attempt ascii. The above was a verbal schematic. The only thing missing is "connect pin 14 of the 74hc14 to VCC and connect pin 7 to ground." I think. If you have schematic tools available, try drawing up my suggestions and posting them. That's a great way of catching design errors, btw.

[Prodos8]

I'd probably go with a circuit using a 555 timer, they seem to be the simplest.

 

Here's a how to with pics for a guncon that could easily be adapted for the atari: http://www.syste.ms/guncon/

[BigO]

ummmmmmmmmmmmmmmmmm... schematic?

Yeah, I know. But I don't have the tools to prettify something for you right now. And I'm not about to attempt ascii. The above was a verbal schematic. The only thing missing is "connect pin 14 of the 74hc14 to VCC and connect pin 7 to ground." I think. If you have schematic tools available, try drawing up my suggestions and posting them. That's a great way of catching design errors, btw.

http://mysite.du.edu/~etuttle/electron/elect13.htm

Look for "relaxation oscillator"

[+SpiceWare]

One challenge is that there is no +5v connection to the joystick to run the circuitry.

The Atarivox plugs into the joystick port and doesn't use an external power source.

[Prodos8]

One challenge is that there is no +5v connection to the joystick to run the circuitry.

The Atarivox plugs into the joystick port and doesn't use an external power source.

The port does provide +5vdc, but the standard Atari joystick cable doesn't have a wire for it. A nine-wire genny cable is very handy for projects like this.

[MiKOTRON]

One challenge is that there is no +5v connection to the joystick to run the circuitry.

The Atarivox plugs into the joystick port and doesn't use an external power source.

The port does provide +5vdc, but the standard Atari joystick cable doesn't have a wire for it. A nine-wire genny cable is very handy for projects like this.

 

I agree a 9 wire cable would be ideal for this project. You could use a 555 running in astable mode with a pot in between pins 7 and 8 to adjust the frequency (timing) of the output pulse. It would work and be awesome as well! Good luck!

 

Oh yeah look up 555 circuit calculators online so that you can figure out the values of your RC circuit. (RC means Resistor Capacitor). Plus build the thing on a breadboard first so that you can play with different RC values to get pin 3 pulsing the way you want it. If you have an oscilloscope you can see the duty cycle of your output pulse. I guess I would want it to be as close to 50 50 as you can get it. That means that when the pulse is triggered, it goes up to 5 volts and stays up at 5 volts for half a cycle then drops to threshold for the remaining half before it goes back up again. It'll be a square wave. Have fun!

Edited May 29, 2009 by MiKOTRON

[+SpiceWare]

The port does provide +5vdc, but the standard Atari joystick cable doesn't have a wire for it. A nine-wire genny cable is very handy for projects like this.

ah - that makes sense, thanks for the clarification.

[cwilkson]

http://mysite.du.edu/~etuttle/electron/elect13.htm

Look for "relaxation oscillator"

Thanks! That's the circuit I was describing. I suggest reading the text description on that page but here's the pic for the lazy people.

For oscillators, it really doesn't get any simpler. BTW, the translation would be a<=>pin1 and b<=>pin2. In this picture, it is assumed that the capacitor is 0.1 microfarads (uF). You'll probably want a bigger value. Try 10uF for starters. If you substitute a 100k pot for the 10k resistor shown, you can have a variable fire rate.

[27ace27]

ummmmmmmmmmmmmmmmmm... schematic?

Yeah, I know. But I don't have the tools to prettify something for you right now. And I'm not about to attempt ascii. The above was a verbal schematic. The only thing missing is "connect pin 14 of the 74hc14 to VCC and connect pin 7 to ground." I think. If you have schematic tools available, try drawing up my suggestions and posting them. That's a great way of catching design errors, btw.

 

heres a good tool (I use it all the time!) http://www.expresspcb.com/ExpressPCBHtm/Fr...ic_software.htm

[cwilkson]

ummmmmmmmmmmmmmmmmm... schematic?

Yeah, I know. But I don't have the tools to prettify something for you right now. And I'm not about to attempt ascii. The above was a verbal schematic. The only thing missing is "connect pin 14 of the 74hc14 to VCC and connect pin 7 to ground." I think. If you have schematic tools available, try drawing up my suggestions and posting them. That's a great way of catching design errors, btw.

 

heres a good tool (I use it all the time!) http://www.expresspcb.com/ExpressPCBHtm/Fr...ic_software.htm

Thanks. I actually have schematic capture software. I just didn't have any on the machine I was borrowing.

[27ace27]

ummmmmmmmmmmmmmmmmm... schematic?

Yeah, I know. But I don't have the tools to prettify something for you right now. And I'm not about to attempt ascii. The above was a verbal schematic. The only thing missing is "connect pin 14 of the 74hc14 to VCC and connect pin 7 to ground." I think. If you have schematic tools available, try drawing up my suggestions and posting them. That's a great way of catching design errors, btw.

 

heres a good tool (I use it all the time!) http://www.expresspcb.com/ExpressPCBHtm/Fr...ic_software.htm

Thanks. I actually have schematic capture software. I just didn't have any on the machine I was borrowing.

 

you're welcome!

[Video]

Cool, but considering how many games only shoot one shot at a time, how useful would it be? (though I could see useing it on left and right on a Track and field type controller )