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Old 21st October 2012, 04:41 AM   #51
Dagwood is offline Dagwood  New Zealand
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Hi Fotis

I had a few issues once a added the IR reciever on an extention cable, have now just folded the legs on the reciever and will drop it throught the chassis, will work fine but wondered wg=hat type of cable would work?

Also the unit does not seem to hold the remote data, each time I power it up I have to go throught the configration process

Other issue is that the motor is not powerful enough to turn the extention shaft and knob full rotation
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Old 21st October 2012, 04:43 AM   #52
Dagwood is offline Dagwood  New Zealand
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Opps....forgot to add photo
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Old 21st October 2012, 06:51 AM   #53
fotios is offline fotios  Greece
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Quote:
Originally Posted by Dagwood View Post
Hi Fotis

I had a few issues once a added the IR reciever on an extention cable, have now just folded the legs on the reciever and will drop it throught the chassis, will work fine but wondered wg=hat type of cable would work?

Also the unit does not seem to hold the remote data, each time I power it up I have to go throught the configration process

Other issue is that the motor is not powerful enough to turn the extention shaft and knob full rotation
Hi Dag
I'm sorry to hear that you still have issues.
1) I allways try to mount the PCB as is on the front panel. In this direction i did the PCB drawing, the IR receiver is placed in 3 to 3.5 cm distance from mot pot shaft on PCB so there is enough space to not be covered from the knob of potentiometer. If there is need to place in a distance the PCB from IR receiver i use stereo screened cable, though most people use simple 3 conductors flat cable without problem.
2) Regarding remote control address, if your handset transmits a true RC5 code there is no case for the micro to not store into its EEPROM and hold the address code. Neverthless, because i did a small mod in your custom code i will take again a look on it to confirm you that is working properly.
3) From your picture, it is clearly that the motor of potentiometer has to turn a relatively heavy load. I can see a long extension shaft, a coupler and 3 supporting holes of the shaft on your cassis. To be sincere, i've never tried a such type arrangement, but if the whole extension armament of shaft is not in perfect alinement then will be "bend" due to the weight of the heavy solid aluminum knob. In such a case, you could turn the knob manually without trouble. But the motor of potentiometer is a unit of small torque and probably will have problem. Additionally - from electrical view - the actual voltage that applied on the motor is just 3.5V, the rest 1.5V from the total 5V of supply is the voltage drop accross the transistors of "H-bridge". It should be noted that these 4 transistor (Q1, Q2, Q3, Q4) are biased into full saturation when the micro activates either of the 2 driver transistors (Q5, Q6) and the base resistors (R1, R2, R3, R4 which are carefully selected to not cause extra voltage drop). The nominal voltage of motor is 4.5V but if this can resolve your problem, you could remove the 5V supply of PCB to Q1 and Q2 and to connect their collectors in an extra supply source of 6V, thus you will have: 6V-1.5V drop = 4.5V exactly as much is the nominal supply voltage of motor. Please take a look on schematic to understand what i described.
I quote bellow - again - the process of remote controll RC5 address initialization:
The microcontroller is programmed to communicate with any RC5 compatible remote control handset. Each handset transmits a unique RC5 address code, e.g. TV address = 0 and Preamplifier 1 address = 16. To initialize the microcontroller for communication with a remote control handset turn off its power supply, wait for a while and turn it on again - causing thus a master reset. The red LED mounted on PCB immediately starts to blink fast for 10 times. Within this time, press firmly the button mounted on PCB until LED stops to blink and remains constantly glowing. Release the button. Now, within 3 seconds, press firmly a button (MUTE is preferred) on remote control handset. If its address code has been stored successfully into micro, the LED blinks slowly 6 times. If we don’t press any button on remote control handset then the TV address code = 0 is automatically stored into micro and the LED does not lit. If the remote control is incompatible with RC5 protocol the LED starts to blink fast for 10 times and then again the TV address = 0 is automatically stored into microcontroller. That is all. The internal EEPROM of microcontroller retains constantly the address code.
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Old 21st October 2012, 08:04 AM   #54
Dagwood is offline Dagwood  New Zealand
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Hi Fotis

Q1 & Q2 or Q1 & Q3?
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Old 21st October 2012, 08:21 AM   #55
fotios is offline fotios  Greece
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Quote:
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Hi Fotis

Q1 & Q2 or Q1 & Q3?
Q1 and Q3. In schematic is clearly shown that the collectors of these transistors are connected in +5V supply rail. Leave Q2 and Q4 (which of emmiters are connected to GND) as is!
Just now i looked in program and i found a small mistake in the beggining of code that causes the need of re-initializing micro each time power is applied! Sorry friend for the confusion, i removed the related command and now everything works OK.
Check please your mail box, you have a new message with the corrected HEX file attached.
Don't forget to make initialization of micro again, then re-apply power to check if everything went OK.
Fotis
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Last edited by fotios; 21st October 2012 at 08:24 AM.
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Old 21st October 2012, 08:36 AM   #56
Dagwood is offline Dagwood  New Zealand
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No need to worry, tested the pot with 5v directly to the terminals and it still got stuck! As you say, a very small misalignment will cause it to fail.

I will have to re-think this now as the whole idea was to keep all of the audio circuitry well away from the high voltage EM84 VU displays.

Option 1, move pot to the front of case and try to sheild it for the VU meters

Option 2, use this setup on a solid state project ive been working on
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Old 21st October 2012, 09:11 AM   #57
Dagwood is offline Dagwood  New Zealand
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Hi Fotis

Thanks very much for the hex update tested and working.

I cannot walk away from this now! Will re-build the chassis to suit direct mounting of the motorised pot wouldn’t be DIY if it was easy!
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Old 21st October 2012, 10:43 AM   #58
AndrewT is offline AndrewT  Scotland
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Hi,
I used an over the counter remote controller.

It works resonably well, but I have a problem that I would like to improve on.

When adjusting the volume control, the digital control/adjusting signals cause a quiet buzzing clicking in the speaker output. Pretty quiet when the vol is stationary.

Is this likely to be motor noise or control circuit noise?
Where do I look to try to find a way of reducing that noise?
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Old 21st October 2012, 11:09 AM   #59
fotios is offline fotios  Greece
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Quote:
Originally Posted by AndrewT View Post
Hi,
I used an over the counter remote controller.

It works resonably well, but I have a problem that I would like to improve on.

When adjusting the volume control, the digital control/adjusting signals cause a quiet buzzing clicking in the speaker output. Pretty quiet when the vol is stationary.

Is this likely to be motor noise or control circuit noise?
Where do I look to try to find a way of reducing that noise?
Hi Andrew
Digital control - included of course the motor of potentiometer - power supply must be separate from this of analog section. That is the best practice, i allways use it and never had interference issues. There is issue if digital and analog section share a common GND node or rail. Motor is noisy during rotation, microcontroller internal oscillator (4MHz) could also add a small noise - be it so inaudible. With a scope you could see this noise on analog signal path. Thus i never had to solve such a problem like that you refer and so i can't enlighten you
Cheers
Cheers
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Old 21st October 2012, 11:34 AM   #60
AndrewT is offline AndrewT  Scotland
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I will try the scope but I suspect the level will be too low to be useful.
The remote circuit and PCBs have their own separate transformer.
The remote control ground is NOT connected to Audio Ground and NOT connected to Chassis.

Thanks for looking after me.
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