Thinkpads Forum

Thanks to Uwe from this topic - http://forum.thinkpads.com/viewtopic.php?f=30&t=91888 that gave me the idea !
And this is what I've done:
LED is 0603 SMD and is implemented in the LCD's locking mechanism. The on/off button is capacitive because I did not wanted to drill the bezel for a standard switch so the sensor and PCB are behind the bezel. The LED is connected with ribbon wire to the PCB in such a way that the locker is usable in tablet mode but it's hard for me to explain how by words- if someone is interested I can make a drawing ....
The IC I've used is AT42QT1012 (one button capacitive sensor) from ATMEL
A few pics:







And a video how it works : http://www.youtube.com/watch?v=hVrFbXIJP4E

Cool stuff, but wouldn't a backlit keyboard be more fun?

Yes you are right ! It's better when the keys are glowing in the dark but it's a way harder to achieve. The key label has to be with some kind transparent inc or plastic ...

bp409 wrote:Yes you are right ! It's better when the keys are glowing in the dark but it's a way harder to achieve. The key label has to be with some kind transparent inc or plastic ...

I think if you had the light escaping from between keys it should be sufficient to illuminate them with scatter light. I've seen it done on some other keyboard, just don't remember where exactly.

Hi,
greeting from Germany

very cool Mod...
where you got the wiring plan ? (excuse my bad english ...)
I m thinking about modding my x201t with this cool and missing part...

Thanks Marcel

Hi Marcel,
If you mean the electronic circuit diagram of x61t ,I don't have it. I've used that all the devices on the display have a power supply (lcd , fingerprint reader, inverter and so on). Main principle is by using a multimeter to find GND pin and a supply pin with needed voltage. In my case I've used fingerprint sensor connector (it is kind a USB 4 pin interface-2 data,1 GND and 1 3,3v power supply). Because the power consumption of the led and it's circuit is very small it doesn't corrupt by any means fingerprint power supply.

Hi,
there is no Problem to find some Power on the mainboard (USBor some else...)...
Im looking for your sheme of your electric work...

witch is shown on your pics...

LG Marcel

Sorry, I miss-understood you,
I've used a basic circuit configuration from chip's datasheet -



I didn't have DTA143 so I've replaced it with some n-mosfet but don't remember exactly it's number. But if you do so ,you have to put an resistor divider before n-mosfet (or at least 100k between OUT and GND in order to get active high output)
Here is the datasheet of the AT42QT1012 - http://www.atmel.com/dyn/resources/prod ... oc9543.pdf
It is pretty easy circuit. As I remember I've played a little with Rs and Cs to get the exact sensitivity I've needed .

Thank`s

so I´ll try

Marcel

Hi,
it`s me again
now i found a suplier for the AT42QT1012 but i`m not sure what you used as sensor?
...
you should sell your thinklight as Option

Your Marcel

You can use any kind of conductive material with surface area bigger than 25mm2 or 5 by 5 mm. I've used 6X6 mm copper foil stripped from PCB. Main principle is , bigger sensor - greater sensitivity (and depending on Rs /Cs as I mentioned above). For more accurate info read the application datasheet ,it will help you a lot.

Hi,

now i probably found a reseller for the chip
and i read some artikles how to "make" my own PCB

how you made yours? I tested a freeware tool called "Eagle"
but as student i´m not tallented in it...

greetings
Marcel

Yes, I've used EaglePCB -> transparent foil negative laser printing -> UV light positive on PCB ->FeCl3 etching, but for such a simple circuit can be used direct pin to pin soldering (if you have a steady hands and good vision).

Any chance I can find a pre-built kit of this...?

Cheers.

I too would be interested in a pre-built kit for this!
What are our chances?