The Magic Touch

The HT231 and my TV stick seems to be born for each other. There is a recessed space in the back of the HT231 monitor for connectors. And it has just enough space for the TV stick. The stick can plug directly into the HDMI port without extension cord and it is secure enough to not disconnect.

I then hook up the USB A/B cable between the monitor and TV stick. Not surprisingly, there is no touch being recognized. I have also heard from previous discussion from freaktab that if I put all 10 fingers (the HT231 is a 10-point multitouch panel). A touch cursor will show up. Indeed. And I can sort of move it around by moving one of my hand. But it jumps around and completely not useable. 

Now it is time for some digging. The freaktab forum has a lot of information scattered around. There is a thread dedicated to touchscreen; however the only success reported so far was those monitors with 2-point multi-touch. I have read the entire thread before I started the project but I am confident that there will eventually be a way to make it work with 10-point multi-touch. Especially since all these new touch monitors are natively supported by Windows 8. There must be some standard which they are all following.

And then, someone reported that with another Android TV box and some custom firmware running kernel 3.10, the touchscreen works automatically. This is a huge encouragement for me.

I have basically 2 options. Try moving to 3.10 kernel (from current 3.0.36+) or try to get touchscreen working with my current 3.0.36+ kernel. The former is a step too big for me. I also recall seeing another interesting thread that is very useful. I decided that I will go making my own kernel.

There are several useful threads related to building kernels. I ended up returning to a thread specific for my TV Stick. Where an experienced forum member who had built custom kernel for the stick. There were reports of working Wi-Fi but Bluetooth does not work.

I decided to just replace my current kernel with the custom kernel. And it worked! Not only Wi-Fi worked. BT also worked! If it was a week ago, that alone would not be too useful for me because my rooted stock firmware is just as good. 

However, I learned about 1 thing. I can also build my own kernel. The member also wrote a thread about beginner's guide to building kernel. Which is perfect for me.

After switching between the 2 threads. I figured out the right source tree and git cloned the source. It didn't took too long to build the kernel. I also found some tool online to extract the kconfig from kernel.img. So I can build a kernel that is as close to the working one as possible. I bring out the flash tool and overwrite just the kernel.img.

And surprisingly, my kernel boots up! I can confirm that my kernel is being used from "About device" page. The Wi-Fi works. But BT does not. Exactly like many has reported. Although with me, the custom kernel works just fine. BT is nice to have but not a deal breaker. I proceed to touchscreen driver.

I see kernel config has several options for touch input and USB touchscreen. I enabled them and build. My stick won't even boot! Complaining No Command. No big deal. I can always revert back. Later I think it was likely because I tried to make certain drivers as loadable modules.

I restart the kernel config and followed the instructions from the thread I mentioned earlier. I carefully created entries for the USB device of my H231, which has Vendor ID of 0457 and Device ID 1057. The only thing not clear was what device type to pick within usbtouchscreen.c since I am using a different touch monitor as the author. I picked one that looks close to my vendor and build my kernel.

When the stick boot up, I immediately notice something different. Although the touchscreen is not working, I see a touch cursor jumping all over the screen. This is a good indication that my stick is now seeing the touchscreen differently. It means I am on the right track.

After some trial and errors, I landed on using the same device type as the author - 3M. Although Hannspree and 3M appears to bare no relationship, it worked! The touchscreen works perfectly! Every point, every corner. My touch is perfectly recognized. My plan is executing exceptionally well. 

I have a Giant Tablet in front of me!