3 Volt Transistor Relay Circuit for Wireless Xbox 360 Controller

[Llamma123]

3 Volt Transistor Relay Circuit for Wireless Xbox 360 Controller

I saw some valuable responses to a similar circuit on a post in this forum thread956-122655 I thought I would start a new thread and hope for the same helpful responses. Thanks in advance.

We have come upon a new learning situation. We like to do some cosmetic mods to Xbox 360 controllers.

Normally all is dark but one 1/4 of the ring around the X logo button. This is done with one SMD LED, in this photo all four are lit as happens every time when the controller is powered on.

When working with a wired controller power can be wasted without any reprocussions. With the wireless controller we need to disable the lighting when the controller goes to sleep. We have access to power that is always on of the appropriate mAh to power the lights but how do we shut them off when the controller is off? Unable to find an already switched power source, the plan is to use one of the indicator LED's to trigger a relay for main power(two AA batteries about 3V). The indicator LEDs are surface mount running at ~2.3 volts @ 20mAh and all have a common ground. I would like to cut the trace going to ground past the LED's and use that power to switch a seperate circuit connected to a higher mAh source.

I am what you might call a prfessional hobbiest and always learning... this is where my knowlege runs out. I know I could use a mechanical relay for a similar function in car 12V electronics, but in this case with a low voltage/amperage source I think a solid state solution is required? Perhaps couple transistors is the way to go or a small logic chip. Ideally the solution would draw little power from the LED circuit as this will effect the brightness of the LEDs. Any input would be greatly appreciated.

 

[itsmoked]

Your description is confused to me.. You want to cut the ground trace and use that power to switch a separate circuit? Ground trace = Power?

If those LEDs are all on only during boot up, why not find the signal that turns them ALL on and jumper that to keep them on when the single always-on-one is on.

Or just glue a new set of LEDs, the colors you want, next to and on the same arc as the existing ones and run them entirely separately from the gametronics, switch them on with a standard tiny toggle switch mounted somewhere.

 

[Llamma123]

The ground trace is the only common trace amongst all the surface mount LED's, when any one of the four is on it will have power going through it on its way to ground, so yes ground trace = power ...I think

In the top photo we see illuminated ABXY buttons, the dome with the X on it, and the two buttons on either side of the dome all of these are normally dark. The lighting was accomplished by adding 10 3mm LED's, those are the ones that need power. And the single surface mount LED seems to be the most likely place to triger from.

The reason only one of the 4 led's are on is to signify which controller 1-4 that particular controller has negotiated with the system. I am not trying to change that as it is useful information to the user.

I think this may give some useful background into what I am doing

http://llamma.com/xbox360/mods/Xbox 360 Controller LED Mod.htm

 

[fsmyth]

Lemme get this straight; you are adding LED's, and you want
them to turn off when the controller enters sleep mode?

If so, and the added LED's have a common cathode, then
simply add a transistor switch from the cathode common to
ground. Find a signal that is activated when the controller
comes out of sleep, and use that to drive the transistor.
<als>

 

[Llamma123]

Yes thats it! That is exactly what I want to do. What type of transistor should I use?

 

[fsmyth]

One with 3 legs.
Just about any small signal transistor will do the trick;
the more gain it has, the less drive it will require.
NPN if your drive signal is positive-going, PNP if not.
<als>