Recently of my experiment how normal audio output signal convert into LEGO Power Functions RC Protocol infrared signal.

My audio command files are specially composed to meet the LPF RC Protocol Combo direct, Combo PWM and Single output mode.

Any MP3 music player with audio socket can act as LEGO Power Functions 8885 IR Remote Control (6034989) and 8879 IR Speed Remote Control (6019910) to send LPF RC Protocol infrared signal.

The demonstration used mobile phone to remote control LEGO Power Functions Motor and Servo Motor forward, backward and PWM in 7 steps.

The basic circuit used 2N3904 NPN transistor to convert MP3 audio output signal into LEGO Power Functions RC infrared signal, to control LEGO Power Functions Motor.

The basic circuit simple but requires higher power to drive.

The advanced circuit used LM393 comparator and 2N2907 PNP transistor to convert MP3 audio output signal into LEGO Power Functions RC infrared signal, to control LEGO Power Functions Motor.

The advanced circuit complex than simple circuit but requires less power to drive.

My LPF RC Audio Command Files Download:

https://drive.google...dit?usp=sharing

Edited August 18, 201410 yr by TechnicRobot

Looks interesting. Do i understand it in the right way, that this if developed further would provide the possibility to let a complex PF creation be controlled by an audio file like: drive - turn - brake - turn- reverse? Could for example an enormous amount of LED by synced to a music song?

Thats quite awesome! This way you can use the entire PF protocol, I especially like the coast and brake functions.

Hi TechnicRobot,

I've been doing more or less the same research as you did with the audio 2 PF. I used a very simple "circuit", I just connected 2 IR LEDs to the audio out as it is mentioned here: http://www.instructables.com/id/DIY-Infrared-transmitter-for-iPhone-iPod/

It works quit good, but the distance it can control the receiver is very short, max 60-70 cm. Have you measured the the maximum distance your amplified circuit can control the receiver?

And also I'm creating the waveform real-time in my android app.

Looks interesting. Do i understand it in the right way, that this if developed further would provide the possibility to let a complex PF creation be controlled by an audio file like: drive - turn - brake - turn- reverse? Could for example an enormous amount of LED by synced to a music song?

right, like the playlist contains a list of different audio (command), or

can compose a long audio file combined with different audio (command). so you can synced to another music

Hi TechnicRobot,

I've been doing more or less the same research as you did with the audio 2 PF. I used a very simple "circuit", I just connected 2 IR LEDs to the audio out as it is mentioned here: http://www.instructa...or-iPhone-iPod/

It works quit good, but the distance it can control the receiver is very short, max 60-70 cm. Have you measured the the maximum distance your amplified circuit can control the receiver?

And also I'm creating the waveform real-time in my android app.

Hi imurvai

both circuit need external power supply to drive infrared LED, i have tested around 3m to 4m is ok, but max distance not measured.

i also want to develop similar app for testing :)

That's very cool, good job.