Transistors or something...

Super Cameraman · Post by **Super Cameraman** » Tue Nov 13, 2007 5:35 pm

I'm a little confused when it comes to electronic components like transistors.

Say I have one circuit with buttons, and then a whole different circuit with things that need buttons. Without directly wiring the buttons from the first circuit to the second, is there a way to uh... wiring them to the second circuit? Does it involve transistors?

If it helps at all, it's for my Guitar Hero controller I'm building, and the controller has one ground, but I need to wire it to a USB controller or a PS2 controller or something, and the buttons don't actually go to the ground, they go to a glop top or something. So each button has two unique contacts.

Sorry, if you can't understand what the heck I'm trying to say. Is there a place that WOULD know how to do this?

loup · Post by **loup** » Wed Nov 14, 2007 9:34 am

It might be nice to have a little better description of what you're trying to do. I'm assuming you're building a guitar hero controller and you want to wire it to either a USB controller or a normal playstation 2 controller, is this right?

What are you trying to do with this controller, are you trying to just make your own controller to play on a ps2 version of guitar hero?

Super Cameraman · Post by **Super Cameraman** » Wed Nov 14, 2007 1:34 pm

Exactly. I want to connect my Frets On Fire controller to a USB controller or a PS2 controller. (Even though I don't have a PS2) Or maybe, a Wii classic controller if anyone figures out how to hack that for GH3!

Right now it's plugged into a MAME interface board. Basically, it gives you 30 or so contacts and one ground and when you attach it to buttons and such it registers as a keyboard button press. The problem is that the interface is attached to my MAME, so I can't really bring it anywhere. (And it has the entire control panel with the joysticks and buttons hooked up to it)

khaag · Post by **khaag** » Wed Nov 14, 2007 2:14 pm

I'm trying to do the same thing (you'll know this if you've read SCM's other topic) and I posted this problem there. It might give a better description of what we're trying to do.

khaag wrote:After 8 solid hours of working, I've managed to put a string on the GH X-plorer controller. (I'm not trying to hijack your thread here Super). Now here's the thing. It does work... somewhat. The buttons make connection but I think I mixed the wiring up somewhere along the way. When you press what would normally be the green, yellow, or orange separately, it plays all 3 simultaneously. And if you press what would normally be the red or blue buttons separately, it plays both red and blue again simultaneously. Now here's the kicker, when you press down on the d-pad, it plays green, yellow, and orange simultaneously. Also, when you strum with the pick, it plays green, yellow and orange again.

I have it wired all to a common ground, and the common ground in turn connected to the string. The positive terminals of each button and the strum-bar are connected to the new contact pads and the pick.

Does anybody have any ideas as to how I could fix this? I have no idea where to start...

Here's a quick recap of the button mixups:

Green --> Green+Yellow+Orange+Strum
Red --> Red+Blue
Yellow --> Green+Yellow+Orange+Strum
Blue --> Red+Blue
Orange --> Green+Yellow+Orange+Strum
D-Pad Down --> Green+Yellow+Orange+Strum
Strum with Pick --> Green+Yellow+Orange+Strum

Super Cameraman · Post by **Super Cameraman** » Thu Nov 15, 2007 1:42 pm

Anyone? Two people desperately need this information!

loup · Post by **loup** » Fri Nov 16, 2007 10:13 am

again, correct me if I'm wrong here, but when you say

and the buttons don't actually go to the ground, they go to a glop top or something. So each button has two unique contacts.

it sounds like you already have a controller that you want to wire your guitar into. Are you certain that the different buttons don't have a common ground? I would use a multimeter to test that.

My suggestion would be to gut whatever type of controller you want to use and just solder to the lines you want to use for the buttons.

I know you can play guitar hero with a regular ps2 controller, but there is no strumming, just pushing the buttons when the notes come up. If you are planning on using it with guitar hero, I would suggest taking apart one of the actual guitar hero controllers and using the circuit board(s) from that

Super Cameraman · Post by **Super Cameraman** » Fri Nov 16, 2007 1:38 pm

Trust me, I traced the lines on the board. 4 of them have one lead in common, and two have another lead in common.

loup · Post by **loup** » Fri Nov 16, 2007 4:08 pm

Please excuse the horrible drawing, but this might work for you

This has the guitar string as ground and uses pnp resistors. If this doesn't work, then I guess you'd have to make the string positive and use npn transistors, but that doesn't seem like it's a direction you'd want to go.

The stuff on the right side of the diagram is all coming off the glop top

loup · Post by **loup** » Sat Nov 17, 2007 9:09 am

After thinking about it, I realized that my diagram won't work quite right as-is, but it's close, you're going to need to modify it a bit. Look here on what you will need to do to modify it.

Super Cameraman · Post by **Super Cameraman** » Mon Nov 19, 2007 3:51 pm

Hmm...

I'm really sorry, I tried to understand the link you gave me, but it's all over my head.

Why won't your drawing work?

I thought with transistors that when you "switch them" they just stay on until you switch them again. This would be a problem because I need it to turn off as soon as power stops going to it.

loup · Post by **loup** » Mon Nov 19, 2007 8:21 pm

Super Cameraman wrote:Why won't your drawing work?

you will need a couple of resistors for each transistor to make it work. You could leave out the resistors and see if the circuit works properly, but no guarantees. R1 (from the site I linked) brings the transistor into its saturation state. R2 isn't required, but it will make sure the transistor is actually turned off when it is supposed to be.

I thought with transistors that when you "switch them" they just stay on until you switch them again. This would be a problem because I need it to turn off as soon as power stops going to it.

for a pnp transistor, both inputs need to be grounded for it to switch on, once the ground is broken from one of the inputs, it will switch off.

khaag · Post by **khaag** » Mon Nov 19, 2007 8:36 pm

I spent about an hour and a half soldering transistors, and resistors, and wiring it all up, and then realized that I stupidly grabbed the wrong box of transistors out of my parts drawer. I used NPN transistors by accident instead of PNP

loup · Post by **loup** » Mon Nov 19, 2007 9:14 pm

khaag wrote:I spent about an hour and a half soldering transistors, and resistors, and wiring it all up, and then realized that I stupidly grabbed the wrong box of transistors out of my parts drawer. I used NPN transistors by accident instead of PNP

Might think about buying yourself a solderless breadboard. It lets you try out your setup before actually committing to soldering it all together

khaag · Post by **khaag** » Mon Nov 19, 2007 10:05 pm

the funny thing is that I have a solderless breadboard. I just chose not to use it.

Super Cameraman · Post by **Super Cameraman** » Tue Nov 20, 2007 4:46 pm

Okay, I get it now, I think.

Does this mean that there needs to be voltage going through the guitar at all times?