Thread: "Transflective" LCD panel with res touch+controler for $101+$36 S+H

Originally Posted by dyne

Is there any way to control the backlight other than the up/down type buttons? I'd like to have an autodimming function and don't mind making my own circuit, but it'd be nice if there were pins that would correspond to something like "apply 3.3v to pin 2 and get 50% brightness" rather than going through a menu.

emm. I don`t think we can do this now. will check with the tech anyway

Originally Posted by dyne

Is there any way to control the backlight other than the up/down type buttons? I'd like to have an autodimming function and don't mind making my own circuit, but it'd be nice if there were pins that would correspond to something like "apply 3.3v to pin 2 and get 50% brightness" rather than going through a menu.

I did actually ask this question a page or so ago. Now that I actually have the PCB in front of me I think it is possible. I already had two of the older style VGA only control boards, which I don't think you can change the brightness on, so I purchased two of the newer ones along with my third panel. Now I have them this is what I have found:

The connector CN13 that has not been added to the board (right next to one of the screen connectors CN18) has an ADJ pin, pin 3 I think. If you follow this track it looks like it connects to a surface mount capacitor and resistor, this resistor then feeds pin 7 of U11. The light in my study is pretty bad, but I think U11 has S142 written on it, which could very well be a PWM controller for LEDs the datasheet of which is this I believe. And sure enough, pin 7 is the brightness control. The datasheet has some pretty good instructions on how this brightness pin works, sounds like it can accept a filtered PWM signal or you can feed it with an analog voltage. I suspect that the resistor / capacitor network that the ADJ pin on CN13 connects to is some kind of filter, so maybe if you jam a PWM signal on that ADJ pin that will do the trick, but you would need to figure out what frequency it would cope with I guess.

This was all at a quick glance, I could be quite wrong. I'll need to actually put some time into it to verify, which I'm not going to do now as I am ill, by brain hurts and I'm hungry.

Spaghetti calls....

Excellent find theBlueLight!

S142 is indeed the order code for MIC2297-42YML PWM LED Driver and it can take an analog voltage as well as a PWM control. The control formulas are already there in the datasheet you've linked to. Thanks!

Originally Posted by theBlueLight

I did actually ask this question a page or so ago. Now that I actually have the PCB in front of me I think it is possible. I already had two of the older style VGA only control boards, which I don't think you can change the brightness on, so I purchased two of the newer ones along with my third panel. Now I have them this is what I have found:

The connector CN13 that has not been added to the board (right next to one of the screen connectors CN18) has an ADJ pin, pin 3 I think. If you follow this track it looks like it connects to a surface mount capacitor and resistor, this resistor then feeds pin 7 of U11. The light in my study is pretty bad, but I think U11 has S142 written on it, which could very well be a PWM controller for LEDs the datasheet of which is this I believe. And sure enough, pin 7 is the brightness control. The datasheet has some pretty good instructions on how this brightness pin works, sounds like it can accept a filtered PWM signal or you can feed it with an analog voltage. I suspect that the resistor / capacitor network that the ADJ pin on CN13 connects to is some kind of filter, so maybe if you jam a PWM signal on that ADJ pin that will do the trick, but you would need to figure out what frequency it would cope with I guess.

This was all at a quick glance, I could be quite wrong. I'll need to actually put some time into it to verify, which I'm not going to do now as I am ill, by brain hurts and I'm hungry.

Spaghetti calls....

Thanks for sharing

We need opinion. Is a Capacitive Touch worth extra $60? We are plan to update the touch to Capacitive but the cost looks a little high. It use the new USB touch controller with only one chip

Originally Posted by 8838.com

We need opinion. Is a Capacitive Touch worth extra $60? We are plan to update the touch to Capacitive but the cost looks a little high. It use the new USB touch controller with only one chip

Only 60 more! That's cheap if you ask me. Right now we have to spend something like 100 more to add capacitive.

Originally Posted by 8838.com

We need opinion. Is a Capacitive Touch worth extra $60? We are plan to update the touch to Capacitive but the cost looks a little high. It use the new USB touch controller with only one chip

Capacitive Touch is totally worth it and $60 is not a high price to pay for the benefits.
Currently I'm using 3M Capacitive touch screen and its very difficult to think going back to resistive touch screens.

When can you start offering the Capacitive Touch option?

We need to place the order at least 1000pcs at a time. That is why we need everybody`s opinion, to see if it worth to do it

If we can get more positive responses. We will place the order soon and should be able to sell in a month or so, depends on how fast the manufacture fulfill the order.

It is a customize capacitive multi-touch screen, the manufacture needs time to make it. Also we need to pay for the mould