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IR Remote Control [message #72817] Fri, 25 May 2012 15:46 Go to next message
skywave-rider  is currently offline skywave-rider
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from the LSAF 2012 thread:

Wayne Parham wrote on Sat, 24 September 2011 01:38
It's not expensive. The remote control itself is a generic universal - just get any one you like. I prefer those that have the up/down and left/right buttons prominent, as opposed to the remotes that have vertically arrayed channel up/down and volume up/down. But any of them will work. Then there's the control board. I'd say by the time the boards are etched and deals are struck, it's probably going to be less than a hundred bucks for the completed control board.

Having said that, it's all still preliminary. The design is done, prototype is working. I can burn chips right now, and can probably have boards etched in less than a month. But I do need to figure out pricing and delivery model. I don't know if I'll make them available directly or just through OEMs. I have plenty of friends in the business that manufacture amps, preamps and kits, so it might make sense to make it available to them, and let them brand them and resell them. I need to work through all that first. Still, by LSAF, the business side should all be worked out.


Wayne, I'm not up to speed on this yet, but it's exactly what I want to be the potentiometer (with or without remote) for my unbuilt preamp. (PASS hotrodded B1.)

Tell me you are making boards and kits...............?

Re: IR Remote Control [message #72822 is a reply to message #72817 ] Fri, 25 May 2012 18:49 Go to previous messageGo to next message
Wayne Parham  is currently offline Wayne Parham
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Registered: May 2009
Illuminati (33rd Degree)

I actually wrote the firmware for the microcontroller on request of a friend and fellow kit maker. I realized there were a lot of amp kit makers and DIYers using remotes that were cheaply made. A motorized pot is not an improvement, except in terms of convenience. In most cases, they are a step back in sound quality because the pot used is el-cheapo. So this is a way to get convenience and high fidelity quality sound on a budget.

I am not planing to make boards and kits, because I want to leave that to the amp makers. However, it isn't hard at all to do. All the "circuitry" is in the firmware - the external circuit is literally just a three-wire interface between processor and RDAC, a single wire from the IR receiver and a power supply. It's super-simple to build one of these things. More wiring for the audio lines than anything else.

So you can wire one up with point to point wiring in minutes. You'll spend more time making the box and hooking up the RCA connectors than you will building the circuit. Most times, you'll want some nice relays for a switcher - to switch sources - and that's a little more circuitry, but still easy, just a garden variety 2N2222 transistor and a relay. Probably want some LEDs too, one for power, maybe one on each source line (same one that is connected to the relay/transistor) to show which source is selected.

Power supply is split, +/-2.5v. Easy enough to do with a couple of LM317/LM337 regulators. The schematic below shows a supply that is probably overkill, having cascaded regulators (7805/7905 followed by LM337/LM317) for extra noise immunity. This level of regulation rivals battery power for noise rejection.

But a complex supply isn't really needed. It could even be done with 1N5222 zeners in series with resistors on each end. The center is ground, and zeners on each side give +/-2.5v. Resistors of appropriate values to limit current, e.g. 22 ohms per side for a 12v supply. So, for example, if you have a 12v DC supply, hook one side of a 22 ohm, 10 watt resistor to the 12v (+) line, the other size to the cathode (band) of an 1N5222 zener, then connect the anode of that first zener to the cathode of a second 1N5222, then the anode of the second zener goes to a second 22 ohm, 10 watt resistor, and finally the other side of that second resistor goes to the (-) line of the 12v supply. Put 10uF capacitors across the zeners, and they provide the +/-2.5v across them. The connection between the zeners is ground, and the connection between the zeners and their resistors is the +/-2.5 outputs.

Use the split supply only to power up the processor and RDAC chips. Wire the relays and any indicator LEDs directly to the 12v supply. They're controlled by outputs from the processor, but their power comes from the 12v line. That limits the current requirements through the zeners and keeps 'em constant.

I like using a stereo VU meter hooked to a couple of the unused RDACs to give a visual indication of the volume setting for each channel. There are six RDACs and only two are needed for the audio signal, so two of the others can be used to drive a volume display. Just wire it as a voltage divider on the power supply, so the wiper provides a voltage proprtional to the volume setting. A schematic for a simple indicator using an LM3916 is shown below. Gotta use blue LEDs, of course. Smile


http://parhamdata.com/preamp_remote.gif

http://parhamdata.com/preamp_remote_driver.gif

http://parhamdata.com/preamp_remote_supply.gif

http://parhamdata.com/preamp_remote_indicator.gif


Re: IR Remote Control [message #72835 is a reply to message #72822 ] Sun, 27 May 2012 15:39 Go to previous messageGo to next message
skywave-rider  is currently offline skywave-rider
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Thanks, Wayne. Putting together the parts order.
I will be utilizing this along with the Pass Hypnotize.

After reading your very complete info I will put together a separate supply so the IR remote can stand by without powering the entire Pre. I'll then run a relay to provide switched power for the rest, as your IC provides for.

I intend to duplicate all IR functions with momentary switches on the front panel, with indicator LEDs for channel and VUs.

If it all goes up in flames I promise to document it for entertainment purposes.

You know, this chip-set you designed nailed exactly what I have been trying to do with this preamp build. Uncanny. Fantastic. I hope I can get it together.

Thanks again.
Re: IR Remote Control [message #72841 is a reply to message #72835 ] Sun, 27 May 2012 19:50 Go to previous messageGo to next message
Wayne Parham  is currently offline Wayne Parham
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Registered: May 2009
Illuminati (33rd Degree)

I agree with you on the front-panel switches. I like to be able to control the device without needing the remote. That's what the BTN lines are for. All you need is a momentary push-button switch for each function. A momentary connection to V- triggers the line.

BTN_PWR is power switch
BTN_SEL selects source
BTN_UP is volume up
BTN_DN is volume down
BTN_LF is balance pan left
BTN_RT is balance pan right

Re: IR Remote Control [message #72879 is a reply to message #72841 ] Thu, 31 May 2012 13:52 Go to previous messageGo to next message
skywave-rider  is currently offline skywave-rider
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Wayne,
I have not gotten the IR receiver (4838) yet, but looking at your build, it appears that an approx. 1/2" hole is sufficient. I will size it when the order arrives, but I am wondering about mounting options for that. Spec sheet assumes circuit board mounting, but I may glue it to the front panel and extend leads. Another option would be to mount it on a perfboard and line the face up with the hole in the panel. So I guess the question is, do you think it will have decent angle of acceptance butted up behind a 3/16" panel with a round hole?
Re: IR Remote Control [message #72880 is a reply to message #72879 ] Thu, 31 May 2012 17:47 Go to previous messageGo to next message
Wayne Parham  is currently offline Wayne Parham
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It's a pretty good receiver, somewhat environment friendly. However, it is a line-of-site thing, so I would try to get the face as close to flush as possible.

Re: IR Remote Control [message #72928 is a reply to message #72817 ] Tue, 05 June 2012 13:16 Go to previous messageGo to next message
Bill Epstein  is currently offline Bill Epstein
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Thanks Wayne.

Question: are you soldering to the pins direct (kinda scary) or should I get a receptacle of some sort? I looked at Digikey and all the chip sockets just have tails for PCBs like the chips themselves.

Do you know of a socket with solder lugs?
Re: IR Remote Control [message #72930 is a reply to message #72928 ] Tue, 05 June 2012 15:19 Go to previous messageGo to next message
Wayne Parham  is currently offline Wayne Parham
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I would definitely socket the chips. Don't get the cheap little tin jobs either, get good gold plated sockets. You're right, they're designed to mount on a printed circuit board. Put it on a perfboard, and solder to the side with pads.

Re: IR Remote Control [message #72964 is a reply to message #72930 ] Sun, 10 June 2012 06:36 Go to previous messageGo to next message
Bill Epstein  is currently offline Bill Epstein
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Registered: May 2009
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Got the Digikey package and I'm suspiciously eyeing the little bit of post that extends thru the perfboard!

index.php?t=getfile&id=793&private=0

Gonna be tough to lasso those with solder, pardner.

  • Attachment: IMG_2544_1.JPG
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Re: IR Remote Control [message #72965 is a reply to message #72817 ] Sun, 10 June 2012 09:26 Go to previous messageGo to previous message
skywave-rider  is currently offline skywave-rider
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Bill, maybe you could use those IC perfboards that RS sells, or similar, which have solder traces and through holes. I am going to try to use those for the chips.
http://www.radioshack.com/product/index.jsp?productId=2102845

http://www.radioshack.com/product/index.jsp?productId=2103799
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