Infrared signal

Wireless & IoT
1

hello,

I want to control an Infrared system. with the USB-UIRT I could extract the Pronto Remote code and I have to pass through a microcontroller and an IR LED.

the signal frequency is 37.7 kHz.

the frame is:

0000 006D 0000 0074 0070 0157 0013 003C 0013 0015 0013 0015 0013 0015 0013 0016 0013 0015 0013 0015 0013 0015 0013 0017 0015 003B 0013 0016 0012 0016 0014 003C 0013 003B 0013 003C 0013 0015 0013 003 C 0013 003B 0013 003B 0013 003C 0013 0016 0014 0016 0012 0015 0013 0015 0013 0015 0013 0016 0012 0015 0013 0015 0013 0015 0013 0017 0014 0015 0013 0015 0013 0015 0013 0016 0013 0015 0013 0015 0013 0013 003C 003C 003C 0015 0012 0017 0014 0015 0013 0015 0013 0015 0013 0016 0013 0015 0013 003C 0013 0015 0013 003C 0015 0015 0013 003 E 0014 0015 0013 0015 0013 0015 0013 0015 0013 0015 0013 0015 0012 0045 0070 0158 0013 003B 0013 0015 0013 0015 0013 0015 0013 0015 0013 0015 0013 0016 0013 0015 0013 0015 0013 003C 0013 0015 0013 0015 0013 0015 0013 0016 0013 003B 0013 003C 0013 0015 0013 003 D 0014 003B 0013 003B 0013 003B 0013 003C 0013 003B 0013 003C 0013 003C 0012 0015 0013 0016 0014 0015 0013 003 D 0015 003C 0013 003B 0013 0015 0013 003 B 0013 003D 0014 0016 0012 0015 0013 0015 0013 0015 0013 0016 003B ​​003D 0013 0013 0015 0015 0013 0013 0016 0014 003 B 003 C 0013 003C 0012 0015 0013 0015 0013 0015 0013 0016 0012 0017 0015 0015 0013 0015 0013 0015 0013 0014 003B 003B 0011 0F76

the LED is connected to a pin I / O of the microcontroller.

I have to convert this code to send it and the receiver can receive the frame, decode and execute the command OFF.

I await your suggestions.

2

USB UIRT being USB is not a good choice for IR on a small micro.

IRman (no longer sold) used serial RS-232.

There are many RC5 code (the most common IR code) projects on AVRfreaks.net, projects section, and elsewhere. You use a $3 IR receiver module and process the serial data that comes from that, as RC5 data frames. Sending IR involves a playback of the received timing of when the IR receiver module’s bits change state. A microprocessor’s hardware timer is often set to twice the 38KHz IR carrier then a pin on the micro toggles at 38KHz. You start/stop the timer to reproduce the IR carrier bursts. Feed that to two or so strong IR emitters.

3

wael_007:
with the USB-UIRT I could extract the Pronto Remote code and I have to pass through a microcontroller and an IR LED.

the signal frequency is 37.7 kHz.

Unless I’ve read it wrong, why would you need to “extract” the Pronto code from a remote using a USB-UIRT ? You seem to already have the Pronto code for some command, you just need to implement the code’s timings. The details of the Pronto code are discussed below. Basically the code contains the on and off times for the modulated waveform to be sent. The timing unit is 1 period of the IR modulation. An IR stream of 5 on cycles followed by off time equal to 6 cycles would be represented as 0005 0006 in the code.

http://www.remotecentral.com/features/irdisp1.htm

The modulating frequency is also in the code, the 6D says it was measured by the learning remote as 38028.9 Hz. The formula at the link above is : Frequency = 1000000/(N * .241246). Let’s call it 38 kHz, a pretty common frequency, which makes each unit of time in your Pronto code worth 26.3 usec (1/38000).