Jumping Jack Flash weblog

Turn your phone into an universal remote control

Posted in hardware, Infrarossi, Sviluppo, Symbian by jumpjack on 10 giugno 2008

This short tutorial shows how to turn almost any cellphone into an universal IR remote control.

CHECK GoogleCode page for downloads and updates

Old post (with detailed instructions about how to build hardware)

How I did it (and credits)

Why it should work also on non-stereo cellphones (but it does not?!?) (see also excel file)

Useful links (explanations of remote control protocols)

Other uses for old phones
Available patents (not mine):
Infrared generator from audio signal source
IR receiver using IR transmitting diode


Ready-made transmitter: irDroid



– a cellphone with stereo audio output (audio left , audio right , ground) or symmetrical audio output (audio+, audio-)

– 2 IR leds

– a wired headset compatible with the phone

– a PC with audio card

– an audio recording software on PC

– an audio editing software for PC or an audio sinthesyzer software for PC

This project does not depend on O.S. used: you just need ANY computer capable of recording audio and create audio files from scratch. Linux, Windows, MacOSX or whatelse makes NO difference.

Please look at this post to know how to:
– build an IR receiver for the PC
– sample a remote control
– (create a WAV file using Audacity program) (not strictly needed: this article describe an alternate method).

Once you sampled all needed buttons of your remote, it’s just a matter of building a proper WAV file for each one of them. If you don’t want to use Audacity to do it manually, you can use SOX program: it creates pieces of “raw” audio file, which joined together build up the final WAV file.

Here you find example scripts (for DOS/Windows environment) which build a WAV file based on binary description of the remote signal. You have to setup the unizeri.bat file to have it matching the sampled signal. Then call create.bat specifying as parameter the “creator file” (unizeri-raw, or unizeri-tv,… ), the final WAV file (testbutton) and the number of additional times you want the command is repeated (at least ONE occurrence will be alway created):

create unizeri-raw testbutton 4

(no extensions required for filenames) (NOTE: script must be run inside SOX folder).

This will result in a tesbutton.wav file which, played on a phone (or on PC, or on any audio capable device), equipped with audio-to-IR converter, to control your device.

The audio-to-IR converter:

It is just a couple of LEDs connected in oppopsite ways to “audio output left” and “audio output right” (for normal phones) or to “audio+” and “ground” (for phones with symetrical audio output like nokia 6680). In symetricl ouptu, Left- and Right- must be connected together (see below).

Audio-to-IR converter:

Connections for nokia 6680:

(10 Ohm resistor not strictly needed)


Study about physics/optical phoenomena involved in this project:

Excel file – how to play a 38000 Hz “sound” through a 20000Hz-capable audio device

Big image summarizing Excel data


Forums about Ledrem:



PLC Forum

PC Tuner

HW upgrade





What can you do with an old cellphone?

Posted in GPS, hardware, Infrarossi, intuizioni, Symbian by jumpjack on 7 giugno 2008

An old nokia series 60 phone (like nokia 6600 or 6680) costs around 50$. But it has:

– bluetooth support

– infrared support

– fotocamera

– internet access

– SMS support

– USB support

– Python support (pys60)

– java j2me  support

Mix all these things together, and you could obtain:

1) 3d foto/video (*)

2) touchscreen (wiimote-like)

3) remote video surveillance

4) Add an IR led to your recipe, and you obtain an SMS-controlled remote-control. (GoogleCode page)

5) Add a bluetooth GPS receiver and you have a GPS antitheft. (GoogleCode page)

6) Home intrusion detection system.

7) Simple guitar tuner.

…any more ideas?

It’s just a matter of writing proper software!

(*) To make 3d photo of moving subjects, or 3d video, you need two separate but synchronized cameras. Bluetooth conection should allow such a synchronization, in such a way that when you shoot a photo on one phone, at the same time it’s shot on the other phone.