Using Android tablet as SIRC remote control (#2)

This is my second program to use a tablet as a remote control. The first one (read here for additional infos) was based on a simple IR-Led plus resistor, placed on the “hidden” serial port present on the tablet’s dongle. Such solution was very cheap, but needed for some firmware modding and and for dongle opening, to solder wires on (sometimes) difficult points. So, I modified the software (and the hardware) to make it easier to install on every “original” Android tablet. The only mandatory request is that the tablet must have a “driver” for USB to RS232 interfaces. I tried with units based on popular PL2303 chip (from Prolific) or CP210x chips (from Silicon Labs) and both were detected (as ttyUSB5). The whole system is shown in the picture below :

Note that the “dongle” is open, but it’s only ‘cause all my devices are always “under testing” 🙂 . You don’t need to “look inside”, just plug the USB to RS232 interface in the USB socket and go. Note that the interface shown in the picture is based on PL2303 chip. Obviously, the USB to RS232 isn’t enough to send SIRC commands to your TV. You must build (or ask to a friend to build for you) this VERY SIMPLE interface :

As you can see, there is one DB9-F connector (for RS232), one resistor, one IR-Led and one diode. With such components, I can control my Sony Bravia TV from up to 1.5 meters distance (aiming the receiver spot). If you add some active components (transistors), that distance can be widely enlarged.

Well, now let’s look at the software. When you install the apk on your tablet and start the program, you will receive a screen like this :

The program was written for 800×480 screen tablets, landscape orientation. For my tests I used a LAVA 7″ (original firmware) tablet. This tablet recognized the USB to RS232 interface and assigned the /dev/ttyUSB5 name to it. My program, actually, uses this name as fixed setting. It will NOT work if the interface is recognized with another name (you will receive an error). Obviously, this can be modified, but I will do it in a next release.

In the “display” box, you can see “cmd: 21” ; this is the default command the device will send to your TV when you touch the button “Send”. This command is the TV-On or TV-Off. If you want modify the command, for example to send a Channel+, type on the numeric keys “16” then touch “Set” and your display will show “cmd:16”. Now, touching “Send” will send the command to your TV that will ( if powered-on ! ) skip on next channel. The “Can” key will erase a bad typed number. Note that this behaviour isn’t particular “user friendly”, just ‘cause I developed the program as a “tool” for my experiments. Not a problem to write some “fixed” keys, more user friendly  🙂

For a list of available commands, you can take a look at the following picture (the red rectangle at the right) :

Note that all the images in this article can be enlarged clicking on the miniatures.

Finally, the apk to be installed can be download directly from this link. It doesn’t exists on “the market”, ‘cause I don’t like that way to distribute software. I think it’s too monopolistic way and I don’t agree with such terms. So, the disclaimer is : TRY THIS PROGRAM AT YOUR OWN RISKit’s my original work, and is not certified or approved by others than me 🙂

8 thoughts on “Using Android tablet as SIRC remote control (#2)

  1. Genial su blog amigo.

    Quiero preguntarle lo siguiente:
    Las tablet basadas en infotmic x210 tienen puerto serial en el adaptador de 24 pines?

  2. Ola Tomas 🙂 ti rispondo in Italiano, perché riesco a comprendere lo Spagnolo, ma non sono capace di scriverlo…
    Non ho esperienza sui tablets basati sul processore infotmic x210, così ti consiglio di provare a cercare sul forum di HcH / TechKnow, dove esiste una sezione dedicata proprio a quel processore. Trovi la URL del forum nella colonna a destra del blog, dove c’è il link al “Robotop’s Place”, che è il mio spazio personale sul forum. Partendo da lì, poi risali alla home page e cerchi le informazioni sulla porta seriale del tablet.
    Saludos Amigo ! ( l’ho scritto bene ? 🙂 )

  3. Oh my goodness! Awesome article dude! Thank you so much, However I am
    experiencing issues with your RSS. I don’t know why I can’t subscribe to it. Is there anybody having identical RSS problems? Anybody who knows the solution will you kindly respond? Thanx!!

  4. Thank you for appreciating ! I’m not so accustomed with RSS and other “social networks” activities, being much “asocial” 🙂 After a specific request of a reader, I added the RSS button in the upper bar, then activated it ; now, if it doesn’t work, I have to indagate… But I will promise to study “how it works” and solve the problem. Sorry for removing the URL on your attached comment, as you can see even on all other posts, my blog’s rules have “no links” at first place 🙂

  5. This looks promising. I was looking for an alternative (read ‘cheaper’) to the Sony S tablet.
    It would be great if it used USB directly, without the RS232. Just a small IR led you could hook up to a USB (not bigger then USB stick). I’d buy that in a flash.
    Looking forward to seeing this evolve.

  6. Hello SilentBob, it’s extremely simple to build a stick with a PL2303 chip, a couple of transistor and IR led. I did this circuit using an USB-RS232 “commercial” interface just ‘cause is very cheap and widely available on the market, but thank you for suggesting to create a “product” around this small gadget. I will think on, seriously 🙂 !

  7. After some googling (is that a word these days?), found this site –removed link– . They use the audio jack to connect the IR led.
    Turns out ther are commercial version already 🙁

    but it’s not USB, so there’s still a market there 🙂

  8. Hello SilentBob. I removed the link, due to “strict policy” of my blog to NOT host commercial links in the comments, but I had a look on that site. Nice idea ! I just have some doubts on the range of the remote, ‘cause I think the output impedence, implemented for headphones, can give only few milliamperes to the IR led. Also, I think they must build a wav file to play “on the fly”, in order to send the command, and they must reproduce many short bursts of 38KHz, that is very high frequency to send out in the headphones output. But still it’s nice idea ! Thank you very much to point me toward this different approach. Good ideas are always a starting point for new ideas 🙂

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