Longer Wires = Slower Reaction Time?


#1

This might be a dumb question but does longer wires from the buttons to the pcb board create slower reaction time?

For some reason my modded mayflash feels more responsive then my TE stick… I used the same sanwa buttons on both to test and the only thing I can see different are the longer wiring on the TE stick… (unless, different pcbs have different reaction times?)

btw, the wires that plugs to the ps3 from the TE stick is longer also… mayflash is like 6 ft only… does that make a difference?

or can it be psycological? :looney:


#2

this question can be adequately answered with google


#3

Wire length makes no real-world difference, and I get less than 1ms latency through my 30m network cable.

The difference will either be in your head of in the PCB circuitry somewhere.


#4

Hmm, I cant think of an equation that relates speed of signals to resistance off hand but I would assume (correct me if im wrong) that the speed of a signal is inversely proportional to resistance of a wire. So the question becomes what is the resistance of a wire.

Resistance = Length * Electrical resistivity / Cross Sectional Area

Shortish answer is yes your signal should slow down, but you wont be able to tell. You are best finding an equation that relates voltage/current/resistance to speed of a signal. And comparing how a 100% increase of wire resistance (read: length) changes your response time.


#5

Er… electricity doesn’t work like that. Electrons act like balls in a tube, you push the ball at one end and the ball at the other end gets moved very quickly (in terms of delay) even if the balls are travelling very slowly.


#6

longer wire does not result in a slower signal.


#7

It’s all in your head.


#8

oh man, guess I failed.

Aren’t things like ethernet cables limited to a finite length due to loss of signal/degradation? This is what made me assume that length is related to signal.

edit: then again, things like power lines are all sorts of long… (but do have a very large diameter… ). I think the formulas that govern this would be interesting to see. Any EE’s around?

edit 2: then again power lines are used for transmitting power. How is this related to a signal?? How does a wire carry 1’s and 0’s? Previously someone mentioned flow of electrons… isn’t current the flow of electrons and therefore governed by ohms law?

oh man, im nerding out right now.


#9

Signal loss does occur over very long distances but controller wise, you will not experience signal loss due to the length of the cable.

One of the reasons why I couldn’t move smoothly from my modded Mayflash to the TE was the height of the joystick. I installed my JLF flat to the underside of the surface, making the stick about 1cm taller. It’s not a lot but it can be the cause. I have to make my motions a bit smaller on the Mayflash and my friends who hold the baltop with a wineglass grip say that they can’t play as well on mine because of the height.

This was my experience, at least. You might have installed your JLF at the proper height.


#10

It’s a digital signal being sent serially, so the values on the line in terms of data are either 1 or 0. Electrically this is done by assigning the logical 1 to +5 volts (or some other nonzero value) and the logical 0 to 0 volts. Or you could make the logical 0 positive and the logical 1 negative; it doesn’t really matter. If the receiving end sees a voltage on the line around 0, it will interpret that a logical 0 was sent; otherwise, if it gets around +5 volts, it will interpret a logical 1. The resistance in a conducting wire is insignificant for this distance, so due to signal attenuation you might get some 4.9xxx volts or something for the logical 1, who knows. It’s not going to be a problem.

Although the drift velocity of individual electrons through a conductor is pretty slow, what we care about is the net movement of electrons through the wire. The propagation speed of current in a wire to effect the current at the other side of the wire is about 75% of the speed of light. So the signal travels on the order of 500 million mph. That’s not a problem either.

edit: Processing speeds on the pcbs would make a much bigger difference; regardless, I wouldn’t expect a noticable difference there. I think USB polling rate might make the biggest possible cause of latency, and if it’s 125 Hz like on computers, good luck detecting half a frame of lag at worst.


#11

Speed and signal quality are different things.


#12

You’re actually correct and incorrect. You’re right in that if you push the first ball in the last ball moves out with very little delay. You’re incorrect in assuming that this means the tube length doesn’t matter. In actuality the balls move along at the speed of sound in the medium of the balls, so if you have a tube of steel balls they’ll translate more quickly than if you have a tube of rubber or plastic balls and if you have a tube 30m long it’ll take twice as long for the ball to propagate out as it would for a 15m long tube.

So, technically, the length of a wire does matter, but not much as the limit is close to the speed of light (electricity propagates very quickly, since it’s an EM wave, but various interactions modify it), so unless your wire is on the order of kilometers you’re not going to notice.

tl;dr: It doesn’t matter.


#13

ya, not really trying to argue. Just trying to understand. Nothing like some technical discussion on SRK!


#14

Of course, I was trying to keep the analogy simple :slight_smile:


#15

Electricity travels at the speed of light.

No.


#16

Not exactly. Whats funny is electrons don’t really move shrug its their ‘holes’ that do.

Longer wires technicaly do create a delay, but the difference is beyond ‘just negligible’.

As someone else mentioned, look at the hardware (the stick throw range/button range/etc)

  • :bluu:

#17
  1. Yes, but those are digital signals. the ‘signal’ is read as the voltage on the line. Because of inherent capacitance and resistance in the wire that can’t be gotten rid of, the signal on the other end gets ‘smoothed out’ and looks less and less like the straight lines that were originally sent.
  2. Most power lines are sent three phase. You’re not ready for that. But the power loss due to wire size and length (both of which affect the inherent resistance in the wire) is the normal ohm’s law equations. P=VI=RI^2 and V=IR. So double the wire length, which doubles the resistance, will double the power loss at the same current. None of this has anything to do with game controllers though.
  3. Power lines have a voltage on them, sorta like compressed electrons in a can. When you connect your light bulb up to it, the electrons have a path through the light bulb to get out, which they try to do because its less crowded through the light bulb than inside the wire. So power lines always have voltage on them, if they’re working. Signal lines (in a common ground pad) have that same build up of voltage/high pressure electrons waiting to shoot out, but there is no where for them to go. The pcb sees this build up and knows the button hasn’t been pressed. When the button is pressed, the signal is connected to ground, which has no compressed electrons in it, just tons of room for the electrons to go to. The electrons shoot out to the spacious ground as quick as they can, so quick that even the wire before the switch shows no pressure or compressed electrons because they’re leaving faster than they are arriving in the wire. The pcb sees the lack of pressure, and knows the button has been pressed.
  4. high voltage = 1, low voltage = 0 (usually, but it can be the other way around.)
  5. Yes, but if the circuit is designed well, the flow of electrons through the signal wires should be at a minimum. We don’t need to push a lot of electrons, we just need to know if there pressure at a point is high or low.

#18

So of course moving electricity through a long-ass copper wire will add a “delay” on the order of nanoseconds or some shit.

This thread did make me think of something else though:
At what point does a standard media cord (anything like TV hookups, a video game controller, computer peripheral, I dunno) need to be to cause signal deterioration over its length? I know using a lot of adapters or a splitter without some sort of amplifier can obviously reduce a signal’s strength but I’m just talking about plain having a long cord. I swear I remember hearing a recommendation about how some USB device or something had like a 12 or 20 foot cord length maximum before problems were introduced because of this. Can signal deterioration eventually cause either a detection delay or lost inputs or whatever?

Sorry for the dumb questions, thanks in advance for any explanation that any of you can offer. Don’t be afraid to get scientific on me because I love that shit, haha. :shy:


#19

Not really. I forget the explanation, but it stemmed from the Hiesenberg uncertainty principle. The main thing you already understand though; no delay that has any impact on anything at all.

That kind of question can’t be answered without talking about a specific type of communication. For instance, if its digital, and they all have CRC type checks built in, there’s no degradation; if its received, its received perfectly, and if it isn’t, its resent by the source. If you take some uber long coiled up length of RCA cable, and use it to connect a digital audio port from a DVD player up to a stereo, the sound quality will be identical to using a short cable. The worst that could happen is that the impedance of the uber long cable is so bad that some packets can’t be understood by the receiver, and have to be resent (with the possibility of ‘skips’ in audio) or just flat not received at all (no sound). But that’d have to be an UBER long cable. The impedance of a cable affects higher frequency signals worse than lower frequencies, so you have to take into account the transmission frequency as well; faster protocols require either higher quality cables (e.g. Cat 5 10 Mips ethernet versus Cat 6 gigabit) or shorter cord distances to manage.

If the transmission was analog in nature, like the red and yellow audio channels over RCA, then the resistance of the uber long cable would attenuate (re:quiet) the signal, while the inductance of the uber long cable would cause worse attenuation of the higher frequency/higher pitch sounds and leave the bass relatively unaffected. Without an oscilloscope to measure though, the difference in sound quality isn’t noticable (even to you damn self deluded audiophiles) unless you start talking 100’s or 1,000’s of feet worth of even the cheapest crappiest cable imaginable. Human ears hear in something like the 200Hz to 20kHz range, while the digital signals are way way higher frequency. If you have no problem with a digital transmission over the cord, you sure as hell won’t have any problem with analog audio over the same cord.

So the lesson here: Audiophiles are crazy, and anyone who buys an $80 Monster RCA cable for digital audio is a damn moron. Extension cords of any kind do not cause lag, period, in anything.

Note: Still a student and quite subject to error. If anyone wants to correct anything I’ve gotten wrong, feel free, unless you’re defending audiophiles :slight_smile:


#20

Thanks a lot for the response, Toodles. :smile: