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geekhack Projects => Making Stuff Together! => Topic started by: taquiro on Fri, 17 April 2020, 18:32:44

Title: Backlight mod
Post by: taquiro on Fri, 17 April 2020, 18:32:44
Hi everybody,

I'm working on a project to add backlight leds to my current ajazz ak33.
For some reason my pcb has pads to solder on leds, but once soldered they wont turn on. On further inspection i notice that the pcb (led)pads were not getting current.

I found a way to wire current to the positive pads and leds will be always on.

So here's where my headache begins: I want to find a way to switch them on or off like the CapsLock led indicator(I don't want backlight always on). I can wire the leds to the CapsLock led indicator line but the backlight leds will only be on when CapsLock is on.

Is there a way to reverse the CapsLock indicator so that my backlight is on except when I turn on CapsLock??

Any other ideas on how to be able to turn off and on leds will be much appreciated.

Thanks in advance.

PS: Sorry if this is a bit confusing, my main language is not English so I try to format and explained everything the best I could.
Title: Re: Backlight mod
Post by: Leslieann on Fri, 17 April 2020, 19:28:01
You're trying to make a single purpose switch perform multiple duties, not an easy thing to do.
It's possible if you cut traces and bypass capslock but an easier way is to just use software to ignore capslock, in Windows you can use Anyhotkey to do it.

Bit of warning.
Where you are pulling power from may not be rated to power that many leds and you could end up frying something. The reason the lights were not getting power before is the company likely used the same pcb on a backlit and non-backlit model they just removed the unnecessary parts. Your first though is probably that you can just re-add them but it's not that simple, there's probably a controller missing.  I would recommend pulling power from as close to the usb port as possible so as not to push too much power through anything upstream from where you are.
Title: Re: Backlight mod
Post by: taquiro on Sat, 18 April 2020, 13:25:00
So, I decided that my times is worth more than 10 dlls, so decided to send back the non-backlit and get the rgb for 10 dlls more. thanks for your help anyways much appreciated.
Title: Re: Backlight mod
Post by: Leslieann on Sat, 18 April 2020, 21:21:02
So, I decided that my times is worth more than 10 dlls, so decided to send back the non-backlit and get the rgb for 10 dlls more. thanks for your help anyways much appreciated.
You're welcome and I completely agree, sometimes it's just not worth the effort.
Title: Re: Backlight mod
Post by: EstebanUG on Wed, 09 March 2022, 13:21:07
Hi dude, i want to replace the switches for a new ones that have an integrated led, I really dont care if this keepd on all the time so how do you put current in your pcb? :o ty so much
Title: Re: Backlight mod
Post by: Maledicted on Wed, 09 March 2022, 16:38:10
Hi dude, i want to replace the switches for a new ones that have an integrated led, I really dont care if this keepd on all the time so how do you put current in your pcb? :o ty so much

It would probably make the most sense to open a new thread for this.

What exactly do you mean though? The board currently has switches with through hole LEDs passing through the housings and you want to replace the switches and don't care about whether or not backlighting is retained? If so, you should be able to desolder all of the LEDs and just leave them out when replacing the switches.

Or are you asking about adding switches that somehow have integrated LEDs to an existing PCB that's not wired for it? In that case, it probably doesn't make much sense to use switches with housings specifically designed for through hole LEDs, since there's nowhere for the legs of the LED to go on a board that doesn't already have vias/holes in the PCB. You probably want more standard modern fare with translucent housings and to add LEDs elsewhere nearby instead.

You should just need to figure out how many LEDs you want to use, and where, and find a source of power to tap into (like the USB port) and use something like an LED calculator (https://ledcalculator.net/) to figure out what value resistors you should need. USB is typically around 5v.
Title: Re: Backlight mod
Post by: suicidal_orange on Sat, 12 March 2022, 07:33:31
Many boards
Or are you asking about adding switches that somehow have integrated LEDs to an existing PCB that's not wired for it?
This is what I read it as.  Most PCBs have the holes and pads for the diodes as the same one is used for the more expensive model with backlighting, sometimes even the resistors are soldered on.