I did this exact thing about 12 yrs ago, and I regret it!! Holtek manufactured a series of encoder and decoder chips (HT12 series) which did all the work, and presented you with a data out for each function. Ive seen them used in old car-alarm systems, and the MING wireless remote kits (once sold by Digikey). These chips are now obsolete, I think. I bought a number of them and now am stuck with how to responsibily get rid of them.
They work quite well, but the problem isnt the chips.
(1) You will have to design and build complex logic to process the decoded IR remote command. I had to make a big 2-sided pcb with all kinds of gate logic. And neat stuff like storing states in non-volatile memory is out of reach. Driving digital volume control is almost impossible. You have to use motor pots, and they WILL fail after 10 yrs as I have found out.
(2) You will have to use Holtek's encoder chips for the remote control unit. This means you have to make your own. And it will be ugly!
Heres my 2p:
Best to bite the bullet and use a PIC. You can do all the remote functionality in software quite easily. You can store the amp. state in its EPROM. You can minimize the hardware complexity immensely. And deal with errors in software. Furthermore, you can use an "industry standard" remote protocol and use one of your spare remote control units or even buy a cheap replacement instead of having to make a remote control unit yourself.
This definitely the way to go. Im seriously thinkgin of gutting my old logic control unit and replacing it with a PIC.
If you need help with the above let me know.
vkj
They work quite well, but the problem isnt the chips.
(1) You will have to design and build complex logic to process the decoded IR remote command. I had to make a big 2-sided pcb with all kinds of gate logic. And neat stuff like storing states in non-volatile memory is out of reach. Driving digital volume control is almost impossible. You have to use motor pots, and they WILL fail after 10 yrs as I have found out.
(2) You will have to use Holtek's encoder chips for the remote control unit. This means you have to make your own. And it will be ugly!
Heres my 2p:
Best to bite the bullet and use a PIC. You can do all the remote functionality in software quite easily. You can store the amp. state in its EPROM. You can minimize the hardware complexity immensely. And deal with errors in software. Furthermore, you can use an "industry standard" remote protocol and use one of your spare remote control units or even buy a cheap replacement instead of having to make a remote control unit yourself.
This definitely the way to go. Im seriously thinkgin of gutting my old logic control unit and replacing it with a PIC.
If you need help with the above let me know.
vkj
I bought a kit off Ebay which I am very happy with. Check out item number 120827077503, its this one, (although I am not sure if it was from the same supplier) I made a little case for it out of hardwood and have not had any problems with it at all. It's very easy to implement.
Worth considering if I were you.
Worth considering if I were you.
Thanks. Took a quick look at it. $42+15 is pretty steep! From the photo, it appears to use a (single?) motorized pot driven by a microcontroller (PIC?). I would however caution you abt the motorized pots. They will become very scratchy, sooner than you think. I bought similar ones from Mouser years back (100kx2, $10) for my amp (Doug Self preamp) and they started failing just a few years later. Now Im planning to replace the whole preamp with PGA2310's. If you use your own PIC you can do a lot more such as add a power relay, monitor the power amp heat sink tempratures, control the speaker relays, add a "sleep" function, control sub-woofer volume, etc.
Another thing I notice is that it doesnt seem to have a "balance" control?
Finally, it is always better to have your pots mounted on the preamp board. Wiring an off-board pot with shielded wire is a mess, and theres always a problem of hum pickup, very difficult to get rid of.
vkj
$42.00 Dollars is a bit steep!?
Try making the same set up your self for less. Impossible, I would say.
I have been running mine for 2 years or so and it is absolutely silent and works flawlessly. If it does show signs of degradind I'll just buy another.
The reason it does not have a balance control is that it is not a pre-amp; therefore it does not have tone controls either.
Try making the same set up your self for less. Impossible, I would say.
I have been running mine for 2 years or so and it is absolutely silent and works flawlessly. If it does show signs of degradind I'll just buy another.
The reason it does not have a balance control is that it is not a pre-amp; therefore it does not have tone controls either.
The pots on the ones on ebay are 100k ohms? Also, the pots themselves are NOT electrically connected in any way to the supplied electronics, correct? In other words the supplied electronics ONLY drives the pots and is not a line control amp. The user connects the pot in the circuit where a manually operated pot would be connected. Is this right??
I always point such questions to this,
FPRC5RX - DIY learning IR decoder
Fully configurable it allows you to build a full R/C system although you need to know how to interface and build for example an "H" bridge driver for the motorised pot.
FPRC5RX - DIY learning IR decoder
Fully configurable it allows you to build a full R/C system although you need to know how to interface and build for example an "H" bridge driver for the motorised pot.
Ok. You havent said what you are using this board for, but for $67 (42+15) you could easliy build an entire hi-end preamp using PGA2310 ($19 from Digikey). Ive just made a small preamp for my bedside music player using a TDA7468 (~$10 from digikey), together with powered speakers. A PIC costs about $3. Besides controlling the TDA chip the PIC drives the 7-segment displays, power relays, muting relays etc. I added a white-noise generator, and by randomly varying the bass and treble controls (of the TDA), the PIC produces a nice "surf sound"! I also added a variable DC power output to provide auxiliary power supply to outboard sources such as MP3 sticks and my old Walkman. This variable power supply is also controlled by the PIC using the PWM output.
As I said, its worth thinking about. Just my 2p, based on my experience. I already have a spare motorized pot waiting to replace the old scratchy one. But the world has moved on since those days
vkj
Hi vkj,
if you have the required skills to do as you say then you may well be right; you have, but I do not. I still think that by the time you have bought the resistors, voltage regulators, chip sets, relays, motorised pot, capacitors, remote control handset and other assorted items, "and" designed and etched your own pcb's you are going to be spending more and that's without taking time taken out of the equation.
I used this volume board to replace a NAD pre-amp and found it to be a revelation in terms of the sound quality. I'm not sying by any means that it is "state of the art", far from it; but if you want a simple workman like solution to a remote control volume it works very well and is very easy to implement, especially for those that do not want to explore the much more technically superior route that you mention.
if you have the required skills to do as you say then you may well be right; you have, but I do not. I still think that by the time you have bought the resistors, voltage regulators, chip sets, relays, motorised pot, capacitors, remote control handset and other assorted items, "and" designed and etched your own pcb's you are going to be spending more and that's without taking time taken out of the equation.
I used this volume board to replace a NAD pre-amp and found it to be a revelation in terms of the sound quality. I'm not sying by any means that it is "state of the art", far from it; but if you want a simple workman like solution to a remote control volume it works very well and is very easy to implement, especially for those that do not want to explore the much more technically superior route that you mention.
Sorry, I was under the impression that you were building a preamp. For your application, I would agree that its not worth it to build from scratch. However, I would urge you to buy a spare motorized pot. They are becoming quite difficult to find.
vkj
If you're interested in an IR controller that provides volume control via RDACs, you might contact Uriah Dailey at BuildAnAmp.com or Bruce Heran at OddWattAudio.com.
The IR chip has a true logarithmic volume curve, better than any potentiometer I've ever seen. This is because it is done with an accurate logarithmic sequence rather than an approximation like potentiometers use. It also has a balance control, mute, power on/off and can select from five inputs (like for tuner, CD, phono, etc). There is one chip for stereo, and another for home theater, which also has a fader control in addition to balance and all the other features.
The IR chip has a true logarithmic volume curve, better than any potentiometer I've ever seen. This is because it is done with an accurate logarithmic sequence rather than an approximation like potentiometers use. It also has a balance control, mute, power on/off and can select from five inputs (like for tuner, CD, phono, etc). There is one chip for stereo, and another for home theater, which also has a fader control in addition to balance and all the other features.
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I can provide schematics, yes. See below. But I would prefer it if you would contact one of those two sources mentioned above for other details, such as availability, pricing, etc. The only way the chips are available is through distributors such as them.
Each individual distributor can tell you what products they can provide, e.g. kits, printed circuit boards, and complete systems in addition to raw chips for DIYers.
Each individual distributor can tell you what products they can provide, e.g. kits, printed circuit boards, and complete systems in addition to raw chips for DIYers.
Thanks for this, it's great. What sort of remotes are available?
Don't worry about the remote thing I just read the text, does Uriah Dailey or Bruce Heran have an email address so I can directly talk to them?
I would be very interested in the kits and PCB artwork and if possible permission for the to be used in a commercial product.
Thanks
Don't worry about the remote thing I just read the text, does Uriah Dailey or Bruce Heran have an email address so I can directly talk to them?
I would be very interested in the kits and PCB artwork and if possible permission for the to be used in a commercial product.
Thanks
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I've sent you a PM. For your commercial queries, see the PM.
To contact Uriah and/or Bruce, you can post on their forums or click on the banner at the top of their forums to take you to their company website homepages. From there, you can find contact information. That's probably the best way to reach them.
To contact Uriah and/or Bruce, you can post on their forums or click on the banner at the top of their forums to take you to their company website homepages. From there, you can find contact information. That's probably the best way to reach them.
Yep, you did it the hard way. You're right in that it works VERY well in a micro. I'm not a PIC guy but I like the Freescale 68HC908 JK1/3/8 series which are 1K 4K 8K respectively. I successfully decoded Samsung commands, transcoded and re-transmitted so that the DLP set and the set top box behaved as a system rather than selecting STB and TV. I wasn't able to do the 38 KHz modulation solely in the micro but an extra 22V10 GAL fixed that up. The most tedious part was capturing all the Samsung commands using an IR reciever and a Tek TDS 3034 scope and print all the screen shots. It becomes pretty obvious what is going on. A long start bit followed by 32 bits where the lfisrt and ast 2 groups of 8 are inverse of each other. Sony is very similar.
Merry Christmas
G²
Merry Christmas
G²
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