Remotely Controlled Motorized Volume Pot.

[Benj]

Of course, there are lot of similar projects offered on the market either as pre assembled units or as kits. Here we have our own that obtained with the use of Flow Code v5.
The unit is remotely controllable thru the use of RC-5 protocol. A ready RC-5 component is offered by the new versions of Flow Code, so there is no need to build a MACRO for it. Just drag and drop the Flow Code RC-5 compo on control panel and configure it thru its properties window. It is so simple! A brief description of unit: It offers the VOL+ and VOL- functions plus STBY and MUTE.
The micro is programmed to communicate with any RC5 compatible remote control handset. Each handset transmits a unique address code, e.g. TV address = 0 and Preamplifier address = 16. To initialize the micro for communication with a remote handset, turn off power supply then turn it on again. 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 RC-5, the LED starts to blink fast for 10 times and the TV address = 0 is automaticaly stored into micro. That is all. The internal EEPROM of micro retains constantly the address code.
Some details about the microcontroller and program code: I did use of everything I had in my stock and so a PIC16F88. This micro includes an internal oscillator module that is very accurate for the given project so there is no need of use an external XTAL. In higher level PICs - like P16F88X - if we don’t configure their internal oscillator it is automatically placed at 4MHz. In P16F88 the INTOSC module should be configured thru OSCCON register or else will not work. That is the reason of the C-code command “osccon = 0x6C;” (INTOSC = 4MHz) in the beginning of Flow chart. The other command “osctune = 0x00;” maybe is redundant, but in P16F88 datasheet is referred that it places the oscillator in its center frequency. The 2nd C-code command “option_reg.NOT_RBPU = 0;” enables the internal weak pull-ups connected at pins RB.0-RB.7 of Port B. This eliminates the need of use external pull-up resistors.
In configuration screen you can see that I have disabled the BOR reset. I did it for two reasons: 1) PIC16F88 offers just one level for BOR, 4Vdc. 2) The motor of ALPS potentiometer consumes enough current (100 to 150mA) during its rotation and so it can cause a sufficient voltage drop to trigger without reason the BOR reset of micro. Higher level PICs offer two - selectable - BOR levels, 4V and 2.1V. It should be noted that, according to Microchip, when both POR and BOR are enabled the MCLR is usually redundant. In the current project, an external MCLR (reset) circuit is used. You can play with different RESET configurations; for me that was a luxury because i had to send the project for test.
In the picture you can see that I have connected the IR receiver with a screened cable of 20cm to the PCB. That offers flexibility in the mounting of IR receiver. I haven't noticed any interference or signal loss issue.

[fotios]

Here the schematics

[fotios]

Here are the correct fcf files.
One for FCv5 users, and one for FCv4 users.

[fotios]

Here is the hex file of project, for use with any programming device.
It should be noted that non registered users of Flow Code like members of diyAudio forums redirected here to see the project in detail, can post their questions and comments. For this reason i opened the thread here in "Electronics Products" Board.

[Benj]

Here some additional information regarding “Power On / Stand By” and “MUTE” functions.
Inside the program code their operation is predicted either remotely or manually thru two push switches mounted on the PCB. Everything that is needed to upgrade your old preamplifier from manually in remotely controlled is included in program code and in hardware. There are ready outputs from PCB to connect one Power relay for activating the power transformer of analog supply, and one Signal relay for mute the outputs. When mains power is applied to preamplifier, instantly the MUTE relay is activated and mutes the main outputs. Power relay remains OFF and waits for a signal. When Power switch is pressed, the Power relay is activated and the analog section transformer is powered. After few seconds the MUTE relay is deactivated and the device is ready to play music. When “Power On / Stand By” switch pressed to put the device in Stand By mode, firstly the MUTE relay is activated and then the Power relay deactivated. In this way, thumbs and pop noises caused during analog power supply stabilization are not audible.
Attached is the PCB drawing in pdf and in 1:1 scale ready for printing in artwork film for people able to make PCBs at home. The silkscreen is also attached. The PCB is a very simple single sided and its size is 143 X 44 mm. It can be splitted in two parts, one for mounting the motorized potentiometer and one for the control circuit.
PCBs offerd under request. Please contact with me using my direct e-mail address for informations.

[Spanish_dude]

Looks really good !
Very well done.

Nicolas

[logon]

Hi all!
I like this project very much because it is so different from every one I saw out there: I really love its way to select different RC handset address-codes!
Anyway, I'm a newbie in Programming and a little (not too much, however) in electronics too; so I have some doubts...
I've just retrieved the following Components List from schematics (hopefully a bit useful for someone):

Code: Select all

BR1 = 1.5A
C1 = 100nF
C2 = 10nF
C3 = 1000µF 16V
C4, C6 = 100nF
C5 = 100µF 16V
C7 = 220nF
CON4, CON5
CON6
D1-D4 = 1N4002
D5 = LED
D6 = 1N4148
IR1 = TSOP34836
LK1-LK7 = 0R or wire-links
Q1-Q4 = MPS2222
Q5, Q6 = BC547
Q7, Q8 = MPSA06
R1, R3 = 22R
R2, R4 = 2K2
R5 = 4K7
R6, R7, R8, R14, R15 = 10K
R9 - 470R
R13, R16 = 100R
SW1 = tactile switch (1555983)
U1 - PIC16F88 or PIC16F819
U2 = 7805
IC SOCKET

and now I do not know what are LK1-LK7 components; from the pic they seem resistors, but then I'm not sure about their values: please could you tell me about these components?
Furthermore, also I'm not too sure about SW1 component: is the following the right one? (Please note it is not as in the pic: it has 4 regular leads for PCB soldering):
http://uk.farnell.com/bourns/7914h-001- ... 4H-001-000
Finally the microcontroller is PIC16F88, but there are so many versions and I do not know what I have exactly to choose:
http://www.microchip.com/wwwproducts/De ... e=en010243
Any suggestions would be greatly appreciated.
Thank you so much!


[Edited in order to update Components List]

[JohnCrow]

Hi
Looking at the pcb layout, I think the LK1 etc components are just wire links.
Though you can buy 0 ohm resistors, ie look like a resistor but act like a wire link. (The ones ive seen have 2 black bands on them)

I'm sure Fotios will clarify this.

[medelec35]

I would agree with John about asking Fotios.
But here is my view.

The links was probably only used to make the PCB tracking layout easier to do and are just tinned link wire.

RE Switch: The Farnell part for PTH (plated Through Hole) normally open contacts tactile switch looks correct to me.

RE Microcontroller :
Dip type looks correct to me:
http://uk.farnell.com/microchip/pic16f8 ... dp/9761500
As these are used with PTH PCB
It's your choice but you may also want to use a IC Socket:
http://uk.farnell.com/jsp/search/browse ... 1%2B203148

Martin

[fotios]

Hi guys
Thank you so much for the assistance and sorry for the delayed reply. I am busy with a... single ended monoblock tube amplifier that i build for a friend - customer. What an experience! Gold, silver, oxygen free copper, tantalum resistors, mylar in oil foil capacitors, teflon... Wow!
Regarding remotely controlled mot pot:
1) Indeed LK are simple wire links, you can use spare leads from e.g. resistors. I use "0R resistors" just... for beauty!
2) Tactile switch is this exactly: http://export.farnell.com/te-connectivi ... tt=1555983
It is the most commonly used, you can use any alternative.
3) You can use any micro with 18pin lead count so that can fit in the 18pin IC DIL socket. The micro also must have internal oscillator module. In the initial project i used P16F88 because i had in stock, now i use a P16F819 that is less expensive, the program is the same simply the configuration settings are changed. I have stored the code for the 16F819 somewhere in my HDD, i have to search for it to upload the HEX code.

@logon
For the rest that you asked me in your private e-mail (i received it and i have read it) i will reply you in the afternoon. Thanks for your patience

[logon]

Hi dudes!
Thank you all for your quick and appreciated reply: now the issue is much more clear for me!

@fotios
I can't wait to realize your project!
Please tell me the exact version of 16F819...
Many thanks for all your appreciated job and replies!

@medelec35
Very nice reply: you pointed in the right direction with further appreciated suggestions, thank you!

@JohnCrow
Many thanks for your first, appreciated and correct reply!

[fotios]

Hi logon
Here is the type of P16F819 i use exactly: http://it.farnell.com/microchip/pic16f8 ... dp/9760784
In the same page that opens, you could see IC sockets, programmers etc. I mainly use the Matrix Multimedia EB006 PIC programmer and i have as a backup the MPLAB ICD2. PICKIT 3 is also a good and economic solution, it can be used with Flow Code software. It is on your own the decision. If you are intented to go deeper in programming i strongly suggest you a bundle of MM FlowCode + MM EB006 programmer. I did it before 3 years and now i can build my programs by alone, i know your problem "audio guy" I had same problems like you in the past. We are here to help you.
Ah! I found the software version for P16F819, attached are the FCF and the HEX files.
A last question: Can you make PCBs at home? Have you tried it sometime? If not please let me know.

[logon]

Hi fotios,
so many thanks for .hex file and for .fcf one too: I thought .hex file was enough in order to flash P16F819 though, and I do not know how to use .fcf file...

Many thanks also for your EB006 suggestion, I'll definitely buy that model!

Regarding PCBs, thank you the same: I just solved ordering a low cost "service" here.

I'll post a related feedback as soon as I'll finish your project, of course... unless I'll return again to ask for more help!

Thank you so very much, really!

[logon]

Hi fotios and everyone!
Sorry if I may sound picky, but I found virtually all the components to finish the project and now I just realized that I miss an information about capacitor types: so I'm here again for your appreciated suggestions...
There are only 7 capacitors in the project:
clearly C3 (1000µF 16V) and C5 (100µF 16V) are electrolytic ones.
C1, C4, C6 have the same value in schematics (100nF), but in the uploaded pic I can see that they do not seem identical and then I'm a bit confused.
Is C1 only a different type (please, which type?), but with the same capacitance, compared to C4 and C6?
Also, which is the type of the 4 red capacitors in the pic (polypropylene, or ceramic, or...)?
Every pointing will be most appreciated.
Thank you very much in advance: I'm learning a lot here, not only about PIC programming!

[fotios]

Hi logon

C1 is the commonly used 100nF multilayer ceramic capacitor for decoupling accross the supply rails of each logic IC.
All rest caps are common MKT (polyester foil) rated at 50V-100V. These used in my project are Philips (those i had in my stock) you can use any brand e.g. ARCOTRONICS (made in Italy).
All capacitors are inexpensive, please don't spend money for polypropylene caps.

[fotios]

Here a WIMA Polyester (PET) 100nF: http://it.farnell.com/wima/mks2c031001a ... tt=1890134
Here a WIMA Polyester (PET) 220nF: http://it.farnell.com/wima/mks2c032201b ... tt=1890135
Here a multilayer ceramic capacitor for C1: http://it.farnell.com/multicomp/mcrr501 ... tt=1216445

[logon]

@fotios
Thank you again for your support... and again!

[logon]

Updated News

Hi fotios,
before to solder the PCB I'm just trying to flash my just arrived PIC16F88 using your "MOT_POT_RC5_FCv4.hex" file, but a warning says what is in the attached pic and then I had not the courage to flash it...
OS Win 7 Pro running PICkit 2.61, PICkit 2 as hardware programmer.
Your valued pointings in the right direction will be really most appreciated.
Thank you very much in advance.

[medelec35]

Hi logon,
It looks like the configuration settings within Flowchart was not set before compiling.
Would you like to try this version?


Martin

[logon]

Hi medelec35,
it does work like a charm!
Thank you so very much, really!

Now I just have to try the programmed PIC on the finished project, but it will take another few days...

P. S.: I've just noticed that, other changes apart, the final portion of your .hex file is smaller compared to original one: is it "normal"?

Many thanks again in advance!

[medelec35]

Hi logon,
You welcome.

P. S.: I've just noticed that, other changes apart, the final portion of your .hex file is smaller compared to original one: is it "normal"?

Many thanks again in advance!

I believe the differences in code size is caused by the different time delays required between the two hex files.

E.g the first hex file you tried (without configuration settings), the Target clock speed is set for 19660800 Hz
With the hex file I posted all I did was change configuration options and the Target clock speed to 4000000 Hz
Since 4000000 Hz is a lot slower than 19660800 Hz, then less delays and NOP's in assembly are required.
This will reduce the code size.

That's my logic anyway and of course I could be wrong?

Martin

[logon]

I've just finished the project and all seemed to work, but the volume pot rotates in a single direction only and in the other one it does not move...
Actually I can not know if the issue is due to modded hex or to an error in my soldering (anyway after some controls it seems ok) and then I'm hopefully waiting for fotios appreciated support about the original .hex file with added the configuration words that PICkit 2 complains...
Thank you very much!

[fotios]

I've just finished the project and all seemed to work, but the volume pot rotates in a single direction only and in the other one it does not move...
Actually I can not know if the issue is due to modded hex or to an error in my soldering (anyway after some controls it seems ok) and then I'm hopefully waiting for fotios appreciated support about the original .hex file with added the configuration words that PICkit 2 complains...
Thank you very much!

Hi logon
Try the attached hex file. I've just tried to program a P16F88 with this hex file thru MPLAB-IDE, using as programmer the MPLAB ICD2. SUCCESS! As target board i used the MM EB006 to test the program in actual mode (unfortunatelly i haven't any ready PCB of the project) using my custom IR-Receiver "e-block" and a LED e-block. I can confirm you that the program works correctly, i've checked both VOL+ and VOL-, also the PWR-ON and MUTE function and to initialize the Address code. I've used both a TV remote control handset (Address = 0) and a Preamplifier remote control handset (Address = 16). Each one can initialize the Address code and can control the P16F88 with success. So, this hex file is a working file.
In the case that you have problems, please let me know. In such a case, i am sure that something is going wrong on your actual hardware and will try to debug it step by step.

EDIT: Maybe this makes sense: On Microchip's MPLAB-IDE, instead "OPEN - FILE" from the Task Bar, i use "IMPORT - FILE" from the Main Menu drop down list.

Medelec's description of circuit was great! Thank you Martin!

[medelec35]

Hi logon,
all I did was change target Clock speed from 19MHz to 4MHz and altered configuration so internal OSC is selected, disabled WDT and LVP.

Did not alter any of the main flowchart.

It should fairly be easy to fault find.

The output's from RA1 and RA2 drive emitter followers which in turn control transistors in a bridge arrangement.

If RA1 is high then Q5 will be on which will turn Q1 and Q4 on. So that means Emitter of Q1 = approx 5V
Collector of Q4 = approx 0V. So that means terminal 1 of CON2 = 0V and terminal 2 of CON2 = 5V

If RA2 is high then Q6 will be on which will turn Q2 and Q3 on. So that means Emitter of Q3 = approx 5V
Collector of Q2 = approx 0V. So that means terminal 1 of CON2 = 5V and terminal 2 of CON2 = 0V

Hence motor should be going in the opposite direction

Both RA1 and RA2 should not be on at the same time.

You can make the motor go one way and take voltage readings from pin RA1 & RA2 first (since if one way RA1 is high and the other way RA2 is high then you know flowchart is OK so must be an issue with the hardware) all the way to CON2, then make the motor go the other way and repeat readings.

Martin

Edit post reply at the same as fotios.

[logon]

I really appreciate your kind and valued help & support!

Hi medelec35,
thank you so much for your appreciated explanation: I have to carefully read it step by step and then I'll follow it.
And please note that my previous doubt was originated from ignorance, not arrogance...
Thank you again, I'll report related results soon.

Hi fotios,
no doubts at all about your program working: I tried (always using "Import Hex" function from PICkit 2.61 software) your recent uploaded hex and now it works like a charm with PICkit 2 programmer too!
Anyway the volume pot still rotates in one direction only...
I've tried a Preamp remote control handset and a CD-Player one: both successfully initialize address-code and both do work only in one direction... so also I am sure that it is a hardware issue!
Soon I'll report my results about board debugging.
Thank you so very much!