How to connect a LED to TE MC Cthulhu to make input lag test video?



I want to test input lag for various systems like NKI did here


I want to test arcade ST, fba (ggpo) on windows7 / XP, Xbox HDR classic mode, PS2 AE capcore

I have a TE w/ MC Cthulhu but I’m not exactly sure how to hook up the LED to my stick, but I guess it should be fairly straight forward.

Can someone help? Thanks.

Official shmupmame Super Turbo thread
Official shmupmame Super Turbo thread

I’m guessing you want an LED as soon as you press your button down?

Connect positive, longer leg, the anode, to the signal wire of the button. Connect the negative, shorter leg, the cathode, to ground. Be sure to put a resistor between one of the legs and the wire, to avoid drawing too much current. 100 ohms or so should do.


Grab a 1k ohm resistor for each button you want to light up, connect one leg to the button’s signal line, and the other leg to one of the LED lines used on the LED panel.

But I have to ask, please separate the boards out. I’m down with testing and all, because of the dual modding, one board can affect the response on the other. I think it’s a little unfair for the MC, since the capacitors on the TE board can affect the button response. But, I could easily be mistaken and the MC could affect the TE board unfairly. I don’t know. I just do know that it’d be more fair for the boards to be tested separately. Better yet, test them individually and together, so people can know if there is an affect.


I usually drive the button lines separately with a microcontroller. I suppose I could go track down some optoisolators and fully separate the electrical circuits that there’s less doubt about that sort of thing.

FWIW, I’m inclined to rig up a transistor to modify the video signal instead of using an LED. That should control for monitor lag somewhat, and provide better timing resolution.


The resistor can be wired to either leg?

So the other leg should go to the LED panel instead of ground like Nerrage said? I’ll look inside the LED panel to make sure I know where to hook this up.

Did I read it correctly? Dual modding TE 360 with MC will introduce input lag??!


I’m not sure I understand you, are you saying you’ll do this test to save me the trouble? :slight_smile:


Forget I said anything. This notion of any lag being completely unacceptable is getting audiophile-level crazy, and I want nothing to do with it.


Toodles, I don’t think most people would care about 2ms lag (like the asus monitor).

But if there is a 1 frame lag ~= 16ms that’s not quite acceptable…


For almost all setups, I would suspect it would barely register in the microsecond range, and usually nano- or pico- range. CAN one board in a dual mod setup affect the response time of a board it’s dual modded with? Yep, sure can, and almost all cases, it’s in that nano- to micro- second range; strictly speaking, its lag, but to think it actually matters or affects play in any way is flat-out, house of 10,000 cats, parachute pants wearing, Crisco-masturbating lunacy.

But the core of science of to test hypothesis. You may be able to test your dual mod and get some average result, but to say that it proves inherent lag in either board is crazy, unless you also test the boards separately. Sure, yes, I think the capacitors on the TE board could make the MC test lest responsive than it would be by itself. But, I could have that backwards; maybe the MC makes the TE crap the bed for some reason I can’t put my finger on. Lots of testing, together and separately, would be needed to show one way to the other.


Papasi, I’ll put something together and have it for you at WCW. I don’t have all the systems you want to test on handy.


Here’s what I did

  1. Connect positive, longer leg, the anode, to the signal wire of the button.

  2. Connect the negative, shorter leg, the cathode, with a 500ohm resistor, then connect it to common ground

Now the LED is lit up all the time and only turn off when I press the button.

I guess it still works for my purpose but it’s not as nice as NKI’s setup…


papasi, reading your thread, I all of the sudden was reminded of this From ben heck .com

PS3 Controller Monitor
New Xbox 360 Controller Monitors

Ben Heck (Heckendorn) sold a few to several game studios for game testing, including Infinity Ward when they develop Modern Warfare 2


in case any of you are interested in the results

PS2 CCC2 ->CRT 8 frames # [media=youtube]JoJzobmdGzU[/media]
PS1 ST ->CRT 4 frames # [media=youtube]JoJzobmdGzU[/media]
DC ST ->CRT 5 frames # [media=youtube]JoJzobmdGzU[/media]

cps2 s-video encoder->CRT 4.5 frames *

cps2 vga encoder->LCD 7-frames *

xbox classic mode->LCD 6-7 frames *

PS3 classic mode->LCD 8 frames

ps2 ae->CRT 6 frames *

w7 aero 8-11 frames (and a lot of dropped inputs) *
w7 fullscreen 7-9 frames *
w7 disable aero 7-8-frames *
xp 6 frames *

w7 aero 8-10 frames (and a lot of dropped inputs) *
w7 fullscreen 7 frames *
w7 disable aero 7 frames *
xp 6 frames *

xp offline fba version 029708 6 frames *

xp offline mame version 0141b 6 frames *

console are tested with 360 TE dual modded with MC, hdmi out to Asus V236H
Emulation are tested on Dell Dimension 9200 2ghz core2duo / ATI 4850 / Asus V236H

thanks ultracombo for lending the ps3 for testing


That’s weird. Flip it around.


How did you measure that .5 frames?


average of 4 frames and 5 frames

updated with xbox & ps3 ssf4 test

xbox SSF4 ryu cr. rh 6 frames

PS3 SSF4 ryu cr. rh 7-8 frames


Any idea what an arcade would be at? Like, is it possible the PS1 version (ST) runs FASTER than arcade?


cps2 = Capcom arcade board. Actually CPS2 is a 2nd (or 3rd) gen Capcom arcade board that is not develop for 1 dedicated game, there are boards named the CPS and CPS3.
The CPS2 similar to a Neo Geo board in the fact they both take large game carts that hold the game ROM data as well as any minor hardware upgrades necessary to run said games. The CPS2 sort of resembled a Large blue game console minus the connectors for Jamma harness, a kick harness and its audio/ video out put and its power connections. THE CPS2 is easy to consoleize or connect to a “supergun” (I always felt the name is inappropriate for what the device does).


Ah, my bad. I thought it was CPS2 emulation.


I’ve heard crisco works quite well… O_o