adding extra "features"

codeman · Post by **codeman** » Mon Sep 05, 2005 7:30 pm

I started a NESp over the summer and got all the electronics working, but then had to go back to school, so it's currently at a standstill. Anyway, I've still been thinking about it and since i'm taking electronics in school I want to try to impelement some extras. My ideas are:

1) Add a tact switch that can switch the built-in controller from player 1 to player 2. Especially handy for SMB3
2) Add another tact switch that puts it on "standby" by turning off the screen. Also handy for SMB3 because it doesn't have a save feature

I know this can be implemented using flip-flops and NAND gates. Seems like you guys know about electronic stuff...any ideas?

Also...anything else electronic you'd love to add to your NESp? I'm always open to new ideas!

usbcd36 · Post by **usbcd36** » Wed Sep 07, 2005 2:44 pm

Um, first of all, tact switches wouldn't work for that. Second, with the controller, you'd need a TPDT (triple pole, double throw) switch at least for the controller (data, clock and latch, or maybe just clock and latch), and they're pretty uncommon. Third, for the screen, you could add a DPDT switch that cuts the ground for the screen and for the controller (so you don't press anything by mistake when you can't see).

S q u e e ! · Post by **S q u e e !** » Wed Sep 07, 2005 2:51 pm

Instead of switching with a button, I just connected two chips from two controllers together and A, B, Up, Down, Right, Left, Power and Ground, then add an DPDT switch so that it turns the power off and on between them, then I can push one button and it counts for both players.

Reaperman@home · Post by **Reaperman@home** » Wed Sep 07, 2005 3:01 pm

couldn't one just rip apart the NES advantage arcade stick for the p1/p2 controller switch? they're cheap enough, $3 should buy one.

I wonder what they look like inside...

Turbo Tax 1.0 · Post by **Turbo Tax 1.0** » Wed Sep 07, 2005 3:11 pm

Reaperman@home wrote:couldn't one just rip apart the NES advantage arcade stick for the p1/p2 controller switch? they're cheap enough, $3 should buy one.

I wonder what they look like inside...

yeah thats wat i was thinking too it would probly work really well too

codeman · Post by **codeman** » Wed Sep 07, 2005 3:24 pm

well, i drew a circuit right after i made that previous post. I just didnt have the time to scan it in to post it. If you go to

users.wpi.edu/~cody/projects

there's something called NES circuit.jpg

A tact switch would work in conjunction with a toggling flip-flop and some NAND gates. There's nothing analog on the ninendo controller, it's all digital, so i configured the gates in such a way that they'll pass anything from the controller to the respective board pins. The standby works essentially the same way.

The N-Channel MOSFET is essentially a switch, in that if it has +5v on the gate, it will have a resistance of about 0.5 ohms...close enough to a short circuit. When the gate voltage drops to 0v, the resistance increases exponentially, creating an "open circuit". There may be micro-amps flowing, and the BJT will draw about 5mA. But i think 5mA is pretty good compared to the 350mA or so that would be drawn if the screen were on.

usbcd36 · Post by **usbcd36** » Wed Sep 07, 2005 3:29 pm

Geez man, what's so good about flip-flops? Yes, I know what they are, but you could just use some cheap switches to duplicate the effect very easily.

codeman · Post by **codeman** » Wed Sep 07, 2005 3:32 pm

usbcd36 wrote: you'd need a TPDT (triple pole, double throw) switch at least for the controller (data, clock and latch, or maybe just clock and latch), and they're pretty uncommon.

i thought you just said it would be hard to get a TPDT switch? Anyway, i just thing it's nice to be able to simply push a button and have something work. Also if you have a slide switch it might get switched off standby accidentally, whereas with a tact switch you can make it flush-mount, making it harder to hit on accident

usbcd36 · Post by **usbcd36** » Wed Sep 07, 2005 4:22 pm

Well, I actually was wrong about needing a TPDT, an SPDT or DPDT will suffice as Squee said. Also, there is no law saying slide switches needn't be flush mounted, there are switches that are just a slider with a notch, fingernail required to operate.

codeman · Post by **codeman** » Wed Sep 07, 2005 4:26 pm

true...i didnt think of that type of slide switch. I still like pushbuttons though. Besides, you wouldnt get to design the solution yourself, so where's the fun in that?

S q u e e ! · Post by **S q u e e !** » Wed Sep 07, 2005 5:45 pm

Because it would work, and be cheaper than an NES Advantage. You can buy the chips on Digi-Key, and can find a pinout in Ben's Book.

codeman · Post by **codeman** » Wed Sep 07, 2005 6:06 pm

what chips can you buy on digikey? Well during my search i found something pretty cool!

http://www.mouser.com/index.cfm?handler ... deid=59533

the datasheet is on the bottom left of the screen. It's a quad analog switch, so instead of using gates, an analog transmission gate pair can be used, and then even analog signals can be passed!
Well i think it's cool...