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Remote relay volume control kit.

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Hi Tom and others,

Originally, we planned on doing a relay board to support the transformers or 24 pairs of discrete resistors. We decided to do the lower cost option first. The micro-control board supports either style of board and a stepped ladder as well. Please indicate other options that you would like to see on the board. The relay board that supports the TX102 would also have 4 input select relays, plus the HT bypass mode.

We should be able to roll out the second relay board shortly. We have the schematic done, and most of the layout.

I am writing SW for the micro board right now. I am implementing the RC5 codec in addition to the Sony.

Do people think that we should store volume settings for each input or stay at the current level. When turning the system on, should we go to the last volume and input or start at zero volume and first input?

Best Regards,

Dale
 
Retired diyAudio Moderator
Joined 2002
harvardian said:
Do people think that we should store volume settings for each input or stay at the current level. When turning the system on, should we go to the last volume and input or start at zero volume and first input?

Dale,

Interesting project. I have given this thought for my own project. My idea was to have a mute button, and on power on, it would be in mute mode. When a volume change takes place, I was going to store the current volume to the eeprom, so that on powerup, I restore to the last volume setting. By keeping the mute button on powerup, this allows to retain the previous setting without the unexpected loudness (you will see the volume level on the display before you unmute it). I would also keep the last known input, storing to the eeprom, then again reading it on powerup. This is just how I was planning on doing mine. My roommate Jordan just got his new boards made, and is making progress for his. Once he gets his working, I will be modifying it to my needs :)

It will be interesting to see how your project works out.

--
Brian
 
Ex-Moderator
Joined 2002
Who's on First??

OK Dale, Brian, Jordan,

I'm a little confused.:scratch:

Are you guys working in competition, parallel but separate, or in coordination with/to each other??

I know Jordan had been working on his, but Dale, you've caught me by supprise. What's the story?

Rodd Yamashita
 

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Actually, Brian and I talked about what Dale is currently doing several months ago, but we kind of decided it would be more work than either of us had time for. Recently I've been toying with the idea putting together a group order of attenuator boards, but I don't know if people would really want the boards without the control. <shrug> I haven't spoken to Dale about his project, but I'm really looking forward to seeing what he creates.

At any rate, I'm still doing my low cost passive volume control project. I decided it'd be more fun than putting a black beauty in my gainclone.

I can list with some certainty the specifics of the project. The heart is a PIC18f452. The inputs are RC5 encoded IR and a motorized pot (it was like $4). The display is an $8.50 backlit 2x16 char LCD. The relay ladder is right out of the Aleph P. The whole project can be done for under $100 (case included), and the code is just a kludge of past projects. It'll be done by May 2nd, because that's when I graduate--I managed to work out undergraduate credit for this one. Pretty cool, right?

Btw Dale, I'd recommend you put in a software option that allows users to choose the turn-on volume [mute vs previous value], and just store it in the same place where you store the volume level.

I have a question for you though. How are you handling the attenuation on power-up? Does your muting relay have a timer to keep things disconnected until your microcontroller finishes initializing? Or does your logic have a defined power-up state (eliminating the need for a timer)? Just wondering..

--Jordan
 
Hi,

We will try out various power on configurations and see what makes sense. We have lots of EEPROM to store stuff into.

Jordan, great minds must think alike :cool: , we are also using a PIC18F452 (or 442 if we don't need the code space).

With all of the control lines, leds, etc... we decided to do a RS232 based LCD controller. A bit more expensive, but we may take advantage of the built-in buttons on one model. Also, the RS232 gives us the ability to do a bootloader. That way, people can upgrade to new software with a PC.

The pricing on our version includes PCB mounted Neutrik connectors (10 at $4.00 ea) and also input selection. We will offer stripped down versions as well.

We will also be offering a ladder version, which offers constant impedence and can support transformers.

jbateman - The Rentron product would not be a good match for this application. You would not get meaningful remote control interface. Plus, you need some smarts for the various mbb and other issues. Plus, it is not that hard to do software decoding.

Rodd, I have started a little business with a friend of mine (www.dipchipelec.com). We decided to invest some time and money to see if we could come up with an inexpensive, but high quality remote volume kit. I didn't really know much about Jordan's intent for his project. We plan on making the design public, but will be selling it in kit form with many options. We also plan on having a few different relay/resistor options. Some people cannot live with the changing impedence, or want to use transformers instead of resistors.

Best Regards,

Dale

P.S. For the ladder based version, we may increase the number of inputs, but eliminate the PCB mounted connectors. One board would work for two chanel single ended. Two boards would be needed for differential.
 
harvardian said:
Hi,

We will try out various power on configurations and see what makes sense. We have lots of EEPROM to store stuff into.

Jordan, great minds must think alike :cool: , we are also using a PIC18F452 (or 442 if we don't need the code space).

With all of the control lines, leds, etc... we decided to do a RS232 based LCD controller. A bit more expensive, but we may take advantage of the built-in buttons on one model. Also, the RS232 gives us the ability to do a bootloader. That way, people can upgrade to new software with a PC.

Hehe. Can't beat a flash microcontroller with an eeprom. I dunno about the RS-232 LCD controller though.. I'll be interested in seeing what you come up with.

Speaking of bootloaders, how are you going to handle your customer's lack of a PIC programmer? I suppose you'll sell pre-flashed PICs? Another option would be to put the in-circuit programmer logic on the board, so that the customers could flash the PICs themselves. Of course, that has its own complications.. Any thoughts?

For debugging and development, I use Dr. Peatman's loader.

--Jordan
 
This looks great, I'm looking forward to seeing some shots of a complete setup, and the availabilty of the stepped ladder version so I can use the Stevens and Billington volume transformers.

What are the control options from the front panel? Is it up down push buttons for volume, or a shaft encoder perhaps?

Here's an interesting solution available as a kit from bentaudio who have a seiden switch controled by a remote operated stepper motor.
www.bentaudio.com/parts/reminst.html
Now that combined with this would be my absolute ultimate control system.
 
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