Truly silent buttons- capacitive touch buttons?


#1

I’ve needed a silent solution for practice for a long time and tried various unsatisfactory mods to existing buttons.
If this has never been achieved, i’m looking for outside the box suggestions to try…

Gamepads and keyboards essentially achieve this and i’m looking to create something influenced by them, obviously needing a large button surface in any form and arrangable in arcade layout and housing.
The two things that create sound in a button are the switch click- easy to replace with a silent version…
and the main offender- force of contact with the housing and as the switch bottoms out. In a pad or keyboard these usually have the rubber press sheet thing behind the buttons that makes it fairly silent.

My first idea is to simply buy 6 backspace/shift buttons or something similar size. some suitable microswitches, and then find some way to essentially house the 6 buttons incorporating a rubber button sheet but in the layout i need (probably having the long shift buttons aligned vertically). Does anyone have any experience or suggestions for how i could go about housing this in a stick? Or alternate ideas?

Many thanks! :slight_smile:


#2

I’ve tried Silent Sanwa buttons, made my own silent pads for Hori Kuro, Sanwa and Seimitsu’s, bought 2 types of silent pads and the most silent button I’ve ever had was the GamerFinger G2’s, expensive but great build quality and the quietest button I’ve ever used.
They aren’t dead silent but there’s no loud slap sound when you press buttons hard and no mushy feeling because they were built around a foam pad, as other silent buttons they added foam to the current design.


#3

Saw on YouTube awhile back some guy put cotton balls in the plunger. Cost next to nothing if cost is a factor.


#4

Yes i’ve tried some of those options too.

A plan is in action and i’ve found a way for SERIOUSLY silent touch-based buttons.

I’m going to buy some cheap capacitive momentary switches like so:

http://www.adafruit.com/images/1200x900/1374-00.jpg

Wire them to the pcb like usual, modify some arcade buttons to not plunge at all with foam stopping it so it has only a slight give. Paint the plungers with a conductive paint. Wire the underside of the plunger through the now nonexistent microswitch hole, to the capacitive touch pad of the switch.

Voila! SILENT AS F*K buttons that engage by touch and still use the normal sanwa/seimitsu housing and plunger.


#5

actually, even better… http://www.ebay.com.au/itm/TTP226-8-way-Capacitive-Touch-Key-Digital-Sensor-Module-Board-/231193238635?pt=LH_DefaultDomain_0&hash=item35d430dc6b

This should work and give me 8 buttons in one, all i need to know is whether the normal wiring will power it enough or if i need to feed extra power to it… any electricians around can help?


#6

That could potentially work, but not in the way you’re thinking. Remember that capacitive touch doesn’t work when you just use conductive paint to nothing. When you use capacitive touch, you are basically adjusting the capacitance of the circuit to ground via your body’s introduction to the system, which the IC is calculating and responding to (I believe Cypress has a lot of app notes on this if you want to read up more on it). You’d have to run a ground wire to the compound somehow, and then hope the IC doesn’t have an issue with an actual grounding of the signal vs. the normally anticipated human interaction. You may find it’s response absolutely terrible.

You’d be better off with literally a gamepad style conductive finger type of PCB, inserted into the button, which would allow for conductive paint setups and have the bonus of running wires to the PCB itself vs trying to tack it into the conductive paint. It also has the benefit of being able to wire directly to the standard setups.


#7

I’m a bit confused sorry… what do you mean “conductive paint to nothing”? what difference will it make running wires from the switch pads to separate pads whether they be paint or something else as long as it’s conductive? or do you mean the switch as a whole won’t work and it doesn’t matter what i extend the pad sensors to?
As far as i can tell, the switch has it’s own power and ground from the separate arcade stick pcb and the sensor function shouldn’t affect ground in any major way? What is the ground wire to the enclosure for?
Please excuse my layman knowledge


#8

Okay, electricity 101, hang on I getting to something here

Here is a basic electrical circuit a Cell (battery) some wire, a switch and a light bulb.

When you close the switch, you complete the circuit and the light comes on. Open the circuit and the circuit is incomplete and no current passes though and the light does not come on.
Arcade buttons are just another kind of switch, the kind that only stays close when you keep the button pushed down.

The basic wiring going to a arcade button works the same way, we are just swapping out the battery and light bulb for an Arcade board. (Yes the arcade board is much more complicated but for now we are ignoring the circuit diagram for the PCB). What you want to do is substitute one style of button for another.

You have your signal or supply wire, but without a return voltage, negative or ground wire the circuit will not work.
You still need to leave a path for the current to go to, you need your return path/wire.


#9

What @Phreakazoid was trying to say is that you can’t just “extend” a capacitive touchpad by connecting wires to it. You’re thinking that they work the same way as physical switches, but they don’t. You can’t take “one side” of a capacitive touchpad to one conductive surface, take the “other side” (there’s really no such thing on capacitive surfaces) and extend to another surface, have them touch and have the circuit closed.

Have a read about capacitive touchscreens:


#10

@Darksakul , I understand that, but i’m confused about how it causes a problem for my idea? The switches i am putting in are still momentary switches that still have a hot wire and a ground wire going where normal button wires go. So why can’t the capacitive type switch work?

@FreedomGundam I have to disagree, from everything i’m reading I can quite simply extend the sensor for this type of switch unless i’m misreading. Example:


"Attach the connecting wire to any conductive object or surface. That surface will become touch sensitive"


#11

Cool, that’s kind of informative.
I dunno, that kinda defeats my understanding of capacitive touchpads, though.
More the reason you should get it and try it out yourself. I’d be happy to be pleasantly proven wrong on this. :slight_smile:


#12

But conducting to what? If you have the extended the capacitive pad say inside of the button, your plan is to use conductive paint or tape (like in the adafruit example) on the plunger (for this rough plan example). The issue becomes how are you making contact with that extended pad?

If the foil/paint/whatever touch the pad by itself… it won’t do anything, because that paint doesn’t actually go anywhere, it’s just floating in space… unless you are somehow touching it to which it then goes through you to ground.

See what I’m getting at? The switch having it’s own power/ground doesn’t really mean anything, because of the way capacitive touch works you need that added path to ground, in terms of capacitive touch it’s relying on your body’s natural adjustment of the capacitance (since you are adding what is basically your own body/small capcitance, in parallel).

Unless I’m misunderstanding your plan? it just sounds like you’re doing something like this:

Capacitive pad -> Hallowed out button -> foil/paint on plunger -> top of plastic button

So the paint touches the capacitive pad, but it won’t make any adjustment on the pad’s reading by it’s lonesome, you’d need to be touching that foil/paint.


#13

I think i see where you’re coming from. To clarify, the pad sensor would be wired directly to the conductive tape on the plunger which would be either wrapped around the whole plunger and directly touched, or on the underside of the plunger as i’ve read they can still work in very close proximity through plastic, so may try that too. Nothing floating in space so to speak. Just an extension of the conductive area the sensor runs it’s checks on.

Have ordered an 8x pad switch for $2 on ebay like the one above, looking forward to playing around with it!


#14

I had thought about something similar a while ago (zero travel of the plunger, eliminating the possibility of it hitting the housing) but during tests on a breadboard I soon realized that the concept didn’t work out for me.
While it’s true that a rather silent result can be archived while hitting the capacitive area (depending on the material of the surface itself - I used cork and it worked quite well), the main issue turned out to be ergonomics:
Constantly forcing my fingers to hover just barely over the surface ended up getting extremely straining to the hand’s muscles in no time and soon after I found myself getting shaky hands accidentally hitting “buttons”.

I have yet to get back to the breadboard, but here’s two other possible solutions I came up with:
A: Grind off the bottom of the button housing right at the lower end of the plunger groove and secure the switch either with rubber bands or elastic glue, e.g. silicone.
This way, the plunger wouldn’t have any surface to hit against reducing the audible noise to a minimum, namely what’s left with the sound that is being created within the switch’s housing.
B: Drop the idea of a standard microswitch all together and build up new buttons from scratch based on a spring loaded plunger with a hall effect sensor not touching anything at all.
This would most likely look similar to a solenoid, except used in reverse.

Personally I prefer the latter idea as it would also allow for analogue outputs based on the plunger’s travel, albeit requiring additional electronics handling the output signal. This would open up solutions such as actual genuinely working star note buttons for Project Diva, Smash Brothers’ analogue movement or shallow/hard presses in DOA. What’s even more interesting is adjustability of deadzone, travel and spring-back force independently of each other, which to me sounds rather sexy~
edit: It’s just that I ain’t got access to a lathe, laser cutter or 3D printer, which renders building a prototype kinda impossible.


#15

hmm good points, perhaps i’ll try leaving a bit of extra space between the top and bottom rows for resting or simply recessing the buttons a little so i can sit on the rim… This one’s just for a silent practice stick so i don’t need to think about real fighting with it.