Hello, here I am, again, with a simple mod for our tablets. In this picture you can see how it’s possible to control a TV set with our tablet using just one resistor and one IR Led ! In the picture you can see the tablet “dongle” (free of the plastic case) with the additional components needed. The circuit is the same proposed at point 3. of my article at this link (in Italian), just the led “color” is IR and the resistor is of lower value to gain some additional emitting “power”.
The IR led anode is directly connected to the 3.3V pad and the cathode to the resistor and this to the TXD pad ; the resistor value is 220 Ohm and must not be decreased in value.
Obviously, the distance you can reach with this small interface is very low, about 20 cm, but I will add in next days a driver circuit to make it working at longer distance. This is just a “proof of concept” (I like this definition).
At this link you can find the zipped APK file (the application) that I’ve written to test the device. Starting the application, you can see 12 buttons keyboard for entering the code to be transmitted, one “display” that shows what you type, and 2 other buttons: one is named “SEND” and simply transmits the IR code while you hold it down, and the other is named “QUIT”, to exit the application.
The program is compiled in debug mode, so without keys or locks. Deflate it from the downloaded zip and copy to sdcard of your tablet, then install it. Obviously, you must have the “unknown source” flag active.
The default command is 21 that in my Sony Bravia TV is the power-on / Power-off ; also test the numbers from 0 to 8 that are for changing channel from 1 to 9 ; for other commands, search on the internet for the Sony IR protocol.
Note: the program needs a small modification in init.rc file (you must be able to do this or the program will open with an exception error). In the init.rc command you MUST disable the console service.
this is the original:
## Daemon processes to be run by init. ## #service console /bin/sh service console /bin/login console
you must change it to :
## Daemon processes to be run by init. ## #service console /bin/sh #service console /bin/login # console
Obviously, this is a first try… so if there are errors, please, don’t shot me ! But give me your feedbacks and suggestions to improve it. Thanks