IRForum

Hi,
I am a newbie to the forum although I have been following for some time - ever since I bought a Send.IR module some months ago.

I have just completed a prototype which emulates a Bang and Olufsen BE04 controller based upon the blog article “Backdoor uPWM Hack on Arduino for Infrared signals using UART”. If I run it using the Send.IR module connected to an Arduino Uno 3, it works perfectly. and I am able to control the radio, CD and a-aux functions on my BeoSound 9000.

However if I replace Send.IR module with a sender based on the circuitry on page 1of the article, it does not work.

I next built another sender based upon based upon another blog article - “Constant current infrared LED emitter circuit”, but again it does not work.

In each case I tested the sender modules using Ken Sheriff’s IRsend routine (http://www.righto.com/2009/08/multi-pro ... brary.html) and found them to be working so I am wondering if the problem relates to the 455Mhz frequency.

Can anyone possibly help me please?

Hi George

That firmware went thru several iterations before posting & I may not have re-tested the 455kHz fully after the final changes were made.
(The original hack provided an inverted IR signal as output...until we figured out another way getting a non-inverted signal using the UART's synchronous clock output.

I will check it out on the scope and get back to you.

In the meantime, if you could post the sketch you are using with your signals that may be useful.

I would also be interested to hear if you have a particular use case for using this uPWM approach vs IRremote or IRLib or direct PWM for generating the IR carrier.

tnx

Hi, and thanks for replying so quickly.

Answering your points in reverse order. The reason I chose the uPWM approach as opposed to IRremote or IRLib was that from my initial reading of the documentation, the latter did not cater for 455kHz without user modification, whereas, you “Backdoor hack” did and, more importantly, when I tested your code (subject to some minor tweaking) I found it worked perfectly.

My development is carried out using Eclipse Sloeber and C++. I am attaching a copy of the main sketch. BnOController.cpp. It uses a library - uPWMArduinoLib -which I created from your hack which I modified to support my BnO requirements. Another library - BnOLib - contains Commands.h which provide the BnO hex codes.

I hope this helps.

Thanks again,

George

Sorry, I initially thought the issue was with the software, but now I see it is with the circuits you built.

please provide the following:

1. Do your own circuits work with normal TV signals at 38kHz?
2. Please post the model # of the IR led & transistor you are using
3. Have you verified the resistor values with a DMM.
4. Please post a photo of your new circuit(s)x2 wired up to the UNO.
5. Can you see the IR from the LEd looking thru a phone camera?

Thanks. I need to rebuild my circuits and I will get back to you once I have completed the task.
Thanks again.
George.