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Cube Switch Modding

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By popular request - guide to using the Cube Switch.

Some time ago I did my first mod putting a Mac Mini into a Cube casing. I had a few Cubes I had been repairing and selling on and had a stock of spare parts and thought it’d be good to use a Cube switch - as they are cool. :headbang:

Others have found my write up on the web and used it and I realize it is probably better to add a few bits to the write up now and make it clearer as it is not just there to remind me how I did it, but needs to be understood by others!

Background Discussion

You can skip this bit if you wnt and just go to the "How To" further down. If you get stuck though come back to this as it may help you understand what you did wrong.

Starting off it is useful to mention here what my investigations with a multimeter into how the switch actually work found out.

The image below is one I took to explain how to hook up to a Mac Mini to control it. Hooking up to a PC switch is the same though:

Cube Switch.jpg

I have labelled the picture above with numbers working downwards from the connector wires of the white connector on the left of the photo. Looking at this connector there are five pins that I have numbered 1,2,3,4,5 working down from the top. The picture shows the connector as it is originally and NOT after conversion. The writing on the picture was my own notes at the time on what to do with the pins to make a working conversion.....

For the original Cube only pins 1, 3,4,5 (counting down from the top) are used. Pin 2 is not connected to anything at all on the board and is just there to make up the numbers.... Of the pins that are connected, this is what I saw when looking at the signals that a real Cube uses:

A. Pin 1 is ALWAYS connected to 5v as long as the machine is hooked up to a mains outet.
B. Pin 2 is not connected.
C. Pin 3 is referred to in other write ups as a “command line”. Basically it gets stuff from the Cube motherboard and I think it actually controls the LED of the Cube proximity switch to stay either “steady” or “pulsing”. If you cut this line to a real Cube then the LED stays off and the volts at that pin are around +5v. However, if you ground (momentarily) the wire then the LED glows strongly - regardless of whether the PC is on or off and this condition persists until the power is physically removed from the computer (unplugged at the mains!) - it glowed at full strength all the time.* Interestingly if you connect the line to ground a second time, then the LED goes off, but as soon as the line goes back to a floating condition again the LED comes back on again persistently. I thought that maybe this function could be used to work the LED function in a correct manner, but I couldn’t find any combination in which using this command line would give me what I needed. I suspect it needs some sort of extra external control circuit from the Mac Cube to make it work properly and merely using a pull-up resistor to 5v or pull down to zero volts is not adequate. While this is all interesting, it didn’t get me anywhere so in my mod I left this pin unconnected.
D. Pins 4 goes to the +ve (plus) side of the power switch connection to the mobo
E. Pin 5 goes to the negative side of the power switch connection to the mobo.

The switch works by connecting pins 4 and 5 together internally when a finger approaches the proximity sensor - i.e. these are the ones that actually turn the Cube on or off according to the proximity switch state.

How to use the switch

Before you do anything a two warnings.

1. In the pictures and description you'll see I have made solder connections directly to my PicoPSU. These connections MUST be made precisely and with a fine tip on your soldering iron. This is not a mod on which to make your first solder joints......the consequences of making a solder bridge (short circuit) between pins on the pico can mean a fried pico or could harm the mobo. If you are using an extender cable on your picopsu I recommend tapping into the wires of the extender instead of directly to the board.

2. While the switch has no visible earth connection, it does still need one. The switch takes it’s ground from the two screws that hold it to the Cube front plate. So when testing this switch you need to either be using it connected to your computer case and that case needs to be earthed so that the switch picks up the ground from the case OR give the switch it’s own local earth by connecting an earth wire (e.g. black from a molex plug) directly to one of the mounting screws. Failing to provide an adequate earth means it’ll do some very funky stuff with shutdown and restart looping. Here is an example of how you could earth the switch:

P1180311.jpg

In that example I have just taken one of the black wires from a Molex plug and connected it to the metalwork of the case. This grounds the case and because the switch is also electrically connected to the case it grounds the switch too....I had to do this because where the power plug enters my case it is a plexi panel instead of the usual Cube metal one, so my case get's no natural earth/ground connection.

Here now is a wiring diagram I made up to show how the rest of the stuff needs to be connected:

Schematic 1.jpg

You will also find this pinout diagram useful in an minute as it details what is what on an ATX power supply connector:

atx_pinout.jpg


So taking all this info, and already having your earth connection, now give the Cube switch what it wants on pins 1,4 and 5 of it’s white connector.

Pin 1 of the white Cube connector MUST be connected to a permanently on 5v line. This is available from any ATX supply as shown in the pinout as pin 9. [Purple wire, +5v standby.] So tap into the purple lead and take it to pin 1 of the little white Cube switch connector. I am using a PicoPSU (which does not have the colours to help you) and I simply soldered the wire to the PCB of the Pico like this:

P1180312.jpg

The photo is kind of deceptive, but the solder joint goes to the fourth tab in from the left hand side as shown on the picture - it looks like it is on the third but it's not - that's just the way the solder joint hardened.....but PLEASE take note of the warning about the consequences of messing up this solder connection.


Pin 4 of the white Cube conn. must be connected to the +ve side of the Power Switch output from the motherboard.

Pin 5 of the white Cube conn. must be connected to the -ve side of the Power Switch output from the motherboard.

Remember that this is not just a normal push switch and realize that it does matter if you hook up the Power Switch outputs from the mobo to the switch the wrong way around.

These three connections and the ground are all that is needed to get the proximity switch working.?


LED function.

Hooking up lines 1,4,5 as indicated above (and making sure the metal plate on which the switch sits is grounded) make the switch work absolutely fine, but the LED in that case will simply be illuminated when the switch has a proximity condition. In other words, it is lit only while the finger is nearby and otherwise is dark. If you want the LED to show the power condition of your computer too then you have to make the mod. shown in my wiring diagram by adding an extra connection.

First, here is the connection at the PicoPSU:

P1180315.jpg

It's a simple wire soldered to pin 16 of the pico board.

That wire needs to be soldered to a 500 (or so) Ohm resistor (value not critical but between 400 and 600 is good) and then the other end of that resistor ends up here:

P1180326.jpg
If you squint at my terrible photo you see it is soldered to the bottom leg (i.e. the one on the right!) of the LED.

( Here's the "science bit" as they say in the ad.s, please skip all this expalnation if you don't care why this mod works: LEDs are pretty simple and they basically glow when a current flows through them.

What I found is that the LED of the proximity switch functions by there always being a positive voltage on one side of it (the anode for techies!) and the negative side (cathode) is “floating” most of the time. Floating means not really connected to anything at all....

However, when a finger comes along and comes near to the switch to turn the PC on, for that brief moment the switch causes there to be a path to earth for the LED and so the LED lights up. When the finger goes away, the earth goes away and the LED cathode side floats again....so the light goes out.

Because of this behavior I figured that to get the LED to be on, we need to provide a path to earth for the cathode side of the LED whenever the PC is on, but remove it when it is off. It’d also be great if we could make it so that the LED glowed more strongly when a finger came close - for instance to trigger a sleep condition.

Thinking back to my old electronics I realized that by giving the LED a pathway to ground by using a suitable resistor that ran in parallel to the pathway that the switch PCB provides I could make the switch glow gently when the machine was on and then more strongly whenever the proximity switch was activated.

Looking back at the ATX pinout you can see that pin 16 of the ATX power supply spec is marked “Power ON”. That pin is actually a signal that comes from the motherboard and is at Ground volts (i.e. zero) whenever the PC is switched on, but is at high resistance or floating when the PC is off. Therefore Pin 16, light green wire, provides exactly what we want. However, we do not want to connect it directly to our cathode leg as we need to moderate the current to earth and not overload the LED.

So If you use a suitable resistor to connect this green line to the cathode wire of the proximity LED then it will light with a soft glow whenever the Cube is powered and a strong glow whenever the proximity condition is met. )


You can if you want just hook up a flying wire from pin 16 of your ATX supply to a resistor and solder the other end of the resistor straight to the LED cathode leg. That’ll work fine - no prob.s. YOU ARE DONE - stop here and congratulate yourself.


Beelzebozo kindly made a little video of the connections to the Pico to help out on this and here is a link to that:
[video=youtube;ZUTc_WuN0VM]http://www.youtube.com/watch?feature=player_embedded&v=ZUTc_WuN0VM[/video]

To avoid clutter I'll mention something else in the next post!!!

Good luck.
 
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I didn't want to clutter up the first post anymore - but here are two alternative ways of getting an LED function:

1. If you don't care about the LED glowing brighter when a finger comes near it and just want the LED to be a basic power on LED then I am told you can just connect the Power LED connector from your MOBO across the LED connectors. You do though need to cut the solder tracks to the LED from the Cube switch PCB so that your new connections do not mess up what the Cube Switch PCB is trying to do.

The advantage is you don't have to cut in to the light green wire of pin 16 of your ATX power supply.

I haven't tried this approach but it has been done and I am told it works!!

2. An even simpler alternative is to take a separate LED and hot glue it behind the Cube LED. This separate LED can be connected to the Power LED output of the mobo (or the HDD activity LED output if you prefer) and if you glue it in the right place it will shine through the Cube LED. I have tried that with the original Mac Mini Cube conversion and it worked fine - that was a micro LED though, so a big fat 5mm LED might not fit there quite so well...
 

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This is great!!

Thank you very much!! I will revisit my sensor later on today or tomorrow and see where it is I went wrong :D

Thanks a lot minihack!!!
 
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Thanks guys.

I wanted to give enough explanation and options to make this (techie) mod a bit easier to manage.

The main points where people can fall down are:

1. In trying to solder onto a picopsu (there's not much room and you need to be quick and fairly accurate) and

2. In doing the optional routing through that plastic connector - again there's not much room and that little plastic connector heats up very quick and could melt. If it starts to go "floppy" (technical word again) then remove the heat and let it all cool down before trying again. It's also easy to apply too much solder and make a bridge between different solder pads of the switch. Inspect everything you do closely before switching anything on!

I am really happy to help though and I hope I have given enough hints on ways to do this that'll get these switches working.....

:wave:
 
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i have 1 question, do you have to solder it directly to the board or can you solder it to the wire and have the same affect? cuz I'm working on a different project where I'm using the g4 cube's proximity switch on another computer and i don't wanna take apart the psu in order to get the switch to work. :D
 

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johna99 said:
i have 1 question, do you have to solder it directly to the board or can you solder it to the wire and have the same affect? cuz I'm working on a different project where I'm using the g4 cube's proximity switch on another computer and i don't wanna take apart the psu in order to get the switch to work. :D
As long as your off the LED you can bypass the board and go right to the wire.
I did that because my solder iron has to big of a tip to get in on the wire off the board into the plug.
So I went resistor off the LED right to the wire.
 
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thank you so much! :D
 
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So I made the mistake of bridging the 5v connection on the picoPSU to the capacitor directly above it. I've having a very difficult time getting them separated. Does anyone know if these connections were supposed to be bridged to begin with?

Would someone be willing to do a quick check w a multimeter? I don't want to fry my motherboard when I attempt to power this on.
 
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cj73 said:
So I made the mistake of bridging the 5v connection on the picoPSU to the capacitor directly above it. I've having a very difficult time getting them separated. Does anyone know if these connections were supposed to be bridged to begin with?

Would someone be willing to do a quick check w a multimeter? I don't want to fry my motherboard when I attempt to power this on.
Gulp. Not good.

I'm not sure that my old Pico does have a cap above the 5v connection. Do some googgling for images of your pico and see what you can find. It is tricky soldering and if you are not directly using the pico (I mean if you are using an extender) then tapping into the purple wire itself is the easiest way to get the connection. Another option is to solder your wire to a small rigid pin and try and shove that down the connection hole on the pico to wedge it in place.


If you think you have bridged a pin by mistake then I strongly advise getting a solder sucker or trying some of that solder wicking stuff that will help you to de-solder the area.

You could also try, if you have just made a slight bridge, using a sharp knife to cut the solder connection that you made by mistake but do check under a magnifying glass and make sure you really have cut the bridge properly before turning on.

I will put a warning about this in the first post.....

Edit: Was it this Pico and capacitor? If so, then unless it is a huge amount of solder then you may have success with a craft knife....if it is a big blob then go for the sucker (!).
picoPSU-120-big1.jpg
Hope it turns out okay for you. Let us know.
 

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