So my SparkFun order came in today. I received some IR LEDs, some IR ICs w/ EEPROM that can record IR signals from any remote, store them and then perform an action when they are detected again (by controlling digital output pins). I also got some Nintendo DS touchscreens and breakout boards for them and a few other little toys.
I’ve already gotten a small touchscreen application put together (I’ll post a video later tonight or tomorrow) and, in the process, discovered a few things that I did wrong. Firstly, I kind of rushed to get a cheap little setup with a touchscreen mounted in a wall plate for an electrical outlet (it’s the first thing I found laying around) but didn’t support the back of the screen and rushed my drawing that I placed under it. The things I learned are as follows:
- Support the back of the touchscreen. I clamped the screen to the faceplate using the metal bracket that came with it, which only pinches the outer edges of the screen. I assumed that this would be best since the pressure of screwing the plate to the bracket wouldn’t result in a false press. The problem with this is that it causes erratic readings when the screen is only pressed from on the top. To get around this I currently have to pinch the screen with my thumb and finger to get a good reading. When used in a real application I would definitely put something over the back to support the screen.
- Take your time if you’re going to place a hand-drawn template behind the touch-screen and make it as straight and level as possible. As I was rushing with this I quickly drew out 6 buttons using a ruler and pen and hastily stuck it under the touchscreen in the back. While the lines are straight, they aren’t all even and the piece of paper itself is slightly crooked behind the screen. You wouldn’t think it would make a huge difference, but it really is a pain in the butt when calibrating because instead of just keeping the same numbers for horizontal/vertical lines you have to take readings for each and every button, which gets old REAL fast.
- The last thing I learned was to be very careful when ordering touch-screens online. I purchased my first Nintendo DS touchscreen from the sparkfun distributor in Toronto (Creatron) and it looks beautiful. I then ordered two more from sparkfun’s website and they were both all scratched and scuffed up. While I don’t care too much because I’m not planning on using them for anything I’m going to use every day, I would have been pretty angry had I planned to use them in some kind of project I would have wanted to display proudly. I’m basically using these for prototyping and have plans to purchase a 17″ touchscreen to put over an old monitor so that I can turn it into a central console for home automation. This experience has caused me to think twice before ordering a more expensive touch-screen (I’ve seen 17″ kits for around $100) from the interwebs, or I’ll at least have to make sure the company has a solid return policy.
Anyhow, that’s it for now. I’m currently researching the IR Protocol that Panasonic uses for their televisions to be able to control my TV. So far the best site I’ve found that describes their protocol is on a site called Davshomepage here. The site has several other manufacturer IR protocols described as well and I will post my progress as I write code and play with IR for the first time. I’m currently charging my camera and hope to have video of the touchscreen project up soon.
**UPDATE** Video is now up here.