Joystick switcher?

[olliraa]

Hi.

 

Running a 7 retro computer setup with video/audio switch and a single crt Sony BVM20F1E. Routing the audio and video is rarher easy, but I'm concerned about having to plug my joysticks (the classic Atari connector type) back and forth between the computers. This puts a real and unnecessary strain for the connectors.

 

So: has anyone ever designed a joystick switcher? 2 input connectors for joysticks and then 7 pairs of outputs to the computers.

 

Any tips?

 

 

 

Lähetetty minun SM-G960F laitteesta Tapatalkilla

 

 

[+Stephen Moss]

I designed one of the Jaguar so that all 4 Worms players could have their own controller.

Although I was going many to one the circuit is basically the same just the direction is reversed. You will need a load of Octal line drivers/Buffers, I think I used 74HC245 because it has tri-state outputs which is really what you otherwise you have line loading loading problems.

 

Connect the same input pins of 7 buffers to each of the joystick input, i.e. Joystick Left to input A0 of each buffer, Joystick right goes to input A1 on each buffer and so on, tie unused inputs to either the 5V or 0V supply rail. Do that for both Joysticks.

 

Next you need a way of enabling the active buffer (i.e. pulling its OE pin to 0V) there are several method of doing this...

1) Program a microcontroller to detect a button press and switch sequentially between each output, the advantage of a microcontroller is that you can use it to drive a seven segment display to show the number of the current output device or an alphanumeric display to display the name of the output device.

2) A two pole 6 position switch, advantage in no programming required but only allow selection of 6 systems.

3) Use a Serial In Parallel Out (SIPO) shift register but this gets a little tricky with the preloading of the requires states, but once loading each press of the selection button should clock the active output to the pin, thereby selecting the next device. However, being 8 bits attached to only with only 7 you need to also attach the 7th output to the serial input so that the output states will circulate around.

 

For all the options you could put a resistor and LED between 5V and the Buffers select/output enable pin (assuming active low(0V), otherwise between the enable pin and 0V) so that an LED labled with the systems name is illuminated to show where the output is going.  

  

[olliraa]

23 minutes ago, Stephen Moss said:

I designed one of the Jaguar so that all 4 Worms players could have their own controller.

Although I was going many to one the circuit is basically the same just the direction is reversed. You will need a load of Octal line drivers/Buffers, I think I used 74HC245 because it has tri-state outputs which is really what you otherwise you have line loading loading problems.

 

Connect the same input pins of 7 buffers to each of the joystick input, i.e. Joystick Left to input A0 of each buffer, Joystick right goes to input A1 on each buffer and so on, tie unused inputs to either the 5V or 0V supply rail. Do that for both Joysticks.

 

Next you need a way of enabling the active buffer (i.e. pulling its OE pin to 0V) there are several method of doing this...

1) Program a microcontroller to detect a button press and switch sequentially between each output, the advantage of a microcontroller is that you can use it to drive a seven segment display to show the number of the current output device or an alphanumeric display to display the name of the output device.

2) A two pole 6 position switch, advantage in no programming required but only allow selection of 6 systems.

3) Use a Serial In Parallel Out (SIPO) shift register but this gets a little tricky with the preloading of the requires states, but once loading each press of the selection button should clock the active output to the pin, thereby selecting the next device. However, being 8 bits attached to only with only 7 you need to also attach the 7th output to the serial input so that the output states will circulate around.

 

For all the options you could put a resistor and LED between 5V and the Buffers select/output enable pin (assuming active low(0V), otherwise between the enable pin and 0V) so that an LED labled with the systems name is illuminated to show where the output is going.  

  

Thank you Stephen Moss for these instructions. Will start investigating

[+Stephen Moss]

Just in case it is not clear during your investigation when I said 7 buffers/line drivers that is per joystick (14 total) so to keep the overall size down you might want to consider making two smaller identical PCB's and mount them one above the other rather than one big one. Then you just need to tie the buffer switching together so that both boards are switched from the same push button/rotary switch.

  

Alternatively, if you want to keep the buffer numbers down you could try hard wiring the fire pins and just switch the directions, then you can route the 4 directions for both Joysticks through a single buffer.

 

Using a serial port switch box might work, but I am by no means certain about that as I cannot recall what is being switched, I have a feeling it is only the serial GND pin