Remote Control

trwh

Member
2002-04-28 2:11 pm
UK
Hi palesha

I really wanted a remote volume control on my Elliott P88 preamp; getting up to change the volume when you've just got comfy is a real pain. A motorised potentiometer seemed an obvious, sonically transparent, and aesthetically pleasing control method. However, I couldn't find any suitable control circuits on the net, and only one somewhat overpriced kit (100USD from Michael Percy audio, not including the pot).

I ended pinching the receiver circuitry schematic from the service manual of an amp made by the same manufacturer as my CD player. This allows me to use the volume buttons on my CD player remote with my preamp. I would post the schematic, but it is based around a PIC, and you would need the same one as used in the amp (I was able to scrounge one as a "spare"). Also, it's a commercial circuit.

Anyway, just a hint!
Tim.
 

trigon

Member
2002-05-09 4:35 am
Canada
Here it is.

Trigon.
 

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I hope you all can download the files from the following location:

http://blu_dot.tripod.com/audio/sch.pdf

http://blu_dot.tripod.com/audio/Final_V1.c

Otherwise give me a mail.

The design is based around a PIC16F84 with several PCF8574's so called IO expanders.
The PIC does the decoding of the RC5 codes send from a standard remote control. Every Device, cd, TV, has its own 5bit address followed by the command, being volume up/down etc.
The decoded RC5 codes are here indeed used for volume control, channel control and steering of an LCD.

The RC5 receiver is a standard device which is sensitive to the particular 38KHz modulated code. The device just gives you serially what you've send.

The micro also decodes the rotaty encoders, also used for volume and channel control.

After decoding all the stuff and updating the respective variables it is send out via I2C to the io expanders.
These control relays for the volume and channel selection.

The SW is in C and written for the CC5X compiler.
The eval version lets you make code of 1k max. But that is enough in this case.

Via a PIC programmer (dont buy that expensive stuff, look for the taite programmer and SW) i download the code into flash.
And that is it folks.


grtz

Simon
 
blu_line said:
I hope you all can download the files from the following location:

http://blu_dot.tripod.com/audio/sch.pdf

http://blu_dot.tripod.com/audio/Final_V1.c

Otherwise give me a mail.

The design is based around a PIC16F84 with several PCF8574's so called IO expanders.
The PIC does the decoding of the RC5 codes send from a standard remote control. Every Device, cd, TV, has its own 5bit address followed by the command, being volume up/down etc.
The decoded RC5 codes are here indeed used for volume control, channel control and steering of an LCD.

The RC5 receiver is a standard device which is sensitive to the particular 38KHz modulated code. The device just gives you serially what you've send.

The micro also decodes the rotaty encoders, also used for volume and channel control.

After decoding all the stuff and updating the respective variables it is send out via I2C to the io expanders.
These control relays for the volume and channel selection.

The SW is in C and written for the CC5X compiler.
The eval version lets you make code of 1k max. But that is enough in this case.

Via a PIC programmer (dont buy that expensive stuff, look for the taite programmer and SW) i download the code into flash.
And that is it folks.


grtz

Simon

Hi blu-line,

I'm also involved in a project using i/o expansion. As far as I know, the 16F84 doesn't have I2S onboard, did you implement that in software? Any particular problem with that?

Jan Didden
 
Hi,

16F84 to decode RC5 and control a preamp. Sounds familiar to me, check my website. Programming here is in assembly, pic is in sleepmode when no code is received. Other features are an encoder on the volume pot to read the position and the pic can control my kenwood tuner via kenwood XS protocol (8bit version).

The RC5 decoding routines are on the site, i put them there because they are based on a statemachine in software. Works very well. Preamp itself is the Audio&Techniek P11 (Hawk audio nowadays). Tube stuff.

Greetings,

Guido
 

yugaaa

Member
2002-01-26 12:41 pm
india
hi palesha,
there is a kit avaliable in chennai and the remote control is based on a philips ic.it has got adjustments for a valume control ,balance,mute ,2inputs,bass and treble.plus a timer .The shop sells it as an addon kit.i personally didnot check the remote control on my amp as i did not want unwanted distortion.