infrared transmitter using avr

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Hi Guys,

I have an broken infrared remote control from a Digital Video Recorder I purchased from China.

Long story short, the remote is not repairable. I do however know the protocol. It is a variation of the NEC protocol.

I was wondering if anyone knows where I can purchase a programmable remote control that uses an avr mcu. I want to be able to specifically change the commands from each button. I do not want to build a circuit board.

I have searched for a programmable remote and simply cannot get the right codes to operate this device. Some codes will work some buttons but they are not the right buttons.

I thought of a learning remote, but I would rather buy something I can program myself.

Anyone?

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There's only 3 bits to a remote.... the resonator, the Ucontroller and an IR transmitter. Are you sure it's not just the resonator that's gone/bad soldering ? Or maybe dry joint on the IR diode ? Or have you already done all that ?
Most controllers nowadays are custom chips, not AVRs/Pics...

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Or to put it otherwise:

There's only 3 parts to a remote....
Why NOT make a board? ;-)

Then again, I'm a PCB producing maniac, so I may be biased.

Embedded design is as much a life choice as any other and I demand the right to legally marry my work.
-------
If it helps, I can PM you my answer in a number of different languages. Ask if you have trouble reading my high-speed-babble in English.

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Except for the coolness of making your own, you can usually find a "universal remote" at Wal*Mart for a couple bucks.

 

"We trained hard... but it seemed that every time we were beginning to form up into a team, we would be reorganized. I was to learn later in life that we tend to meet any new situation by reorganizing. And a wonderful method it can be of creating the illusion of progress while producing confusion, inefficiency and demoralization." Petronius Arbiter, approx. 2000 years ago.

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The so-called JP1/JP1.x remote controls don't use an AVR MCU, but they're incredibly flexible, even more so if you buy or build the interface hardware to program them with a PC (as opposed to programming them manually). I use an FTDI 'TTL-232R-3V3-WE' USB cable with a 2x3 connector attached to mate with the 6-pin header on the remote, but I've built all 3 variants of the RS-232 interface as well.

Coincidentally, I posted about this a few days ago. Check out the URL/forum referenced in that post for a lot more detail.

You don't say where you live, so I don't know how easy it would be for you to find one of these JP1/JP1.x remote controls, but if you can get your hands on one, you should be able to configure it for your DVR and also to do almost anything else you want. (I've programmed my URC-8820 remote control to do the 30-second forward/reverse on my DVR with presses of the Vol+/Vol- buttons.) Even devices not directly supported by a JP1/JP1.x remote can be programmed with a so-called "device upgrade" to support almost anything out there for which the IR protocol is recognizable, but this will require interface hardware and PC programming.

HTH....

Bill

Last Edited: Fri. Aug 5, 2011 - 08:47 PM
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I once had job where people from around the world would send me remotes from VCRs that they were able to purchase in their local countries. I would analyse the codes for the common functions like play, record, fastforward, reverse, and stop and reproduce them so that the local VCR could be controlled by our company medical equipment.
I would have to record a sequence from a button press using a digital storage scope and then determine the ones and zeros of the code and the sequence/structure of the remote's command. It would take about three hours per remote to reproduce the elementary command set. I didn't at the time know about standards in the IR world.
How do you know that this is a varient of the NEC format? As an above poster suggested, wouldn't it be possible to get a 'universal remote' that records the IR sequence from an existing remote's button press? Or do the universal remotes simply have three or four common IR standards and use a set of DIP switches to select between one of the standards? Does the company in China that made the VCR have any information on the remote or an inexpensive replacement? They must have tens of thousands of them.

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Simonetta wrote:
How do you know that this is a varient of the NEC format?

i used my logic analyzer. The remote works at 38KHz.

I had written some code last year to read the address and the command from a DVD player remote I had here which was similar to the NEC format. The DVD player is a Magnasonic, purchased here in Canada. The code I wrote just shows the address and command in hyperterminal, when a key is pressed.

This broken DVR remote happens to be the exact same address (0) and most of the commands are the same as those in the DVD player remote. There are some missing commands like power ON, pause, and others.

The reason I can't use a programmable remote is because the pause button may become Power, and the rewind button would become pause, left button would become down, etc... There are soooo many remotes, they all have one problem or another working with this DVR.

I don't want a circuit board with wires, I would rather use an existing remote that I can reprogram.

The existing remote can't be fixed. It is sealed and can't be opened unless it is destroyed. The buttons aren't really buttons, they are moulded to the keypad and that is the problem they stick on on when pressed, causing the DVR to go crazy.

I tried to get a replacement, but I can't find the right one.

I have a remote control with a 20 pin encoder chip, I was thinking of using it with a 20 pin avr just modify the circuit and code to work.

It would be easier to get one where I don't have to cut any wires. It must be reliable.

Simonetta wrote:
As an above poster suggested, wouldn't it be possible to get a 'universal remote' that records the IR sequence from an existing remote's button press?

This is what I will have to do if I cannot find another solution.

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newbie123 wrote:
The reason I can't use a programmable remote is because the pause button may become Power, and the rewind button would become pause, left button would become down, etc...
Sorry if I'm missing something here, but did you check that URL (Rob Crowe's 'JP1 Remotes' forum) that I referenced? It seems (with all due respect) that either I'm not following you or you're not following me. :)

There are vastly different levels of "programmable" in the phrase "programmable remote". You can (with very few restrictions) completely reprogram any button on a JP1/JP1.x remote control to send whatever command you like. Isn't that pretty much exactly what you're trying to do?

Furthermore, as I'd stated earlier, if the JP1/JP1.x remote you buy doesn't support a particular device/protocol, you can simply add support for that device/protocol to the remote by programming it in as a "device upgrade", using an interface cable (that you buy or build) and a computer.

A JP1/JP1.x remote control is way more capable than the ordinary "universal/programmable" remotes sold in your average store. Unfortunately, this capability is not "trumpeted" by the JP1/JP1.x remote control manufacturers.

Of course, as you know, a so-called "learning" remote would work too, but the JP1/JP1.x remotes (several of which support "learning" too) can provide equivalent functionality (and more) with far less flash/EEPROM usage.

I don't know what's available in Canada, but here in the USA, the RCA 'RCRP05B' ($17.99 at Best Buy, $15.64 at Amazon) and the UEI URC-8820 (hard to find -- Amazon used to sell them) and the UEI URC-10820 ($12.98 at Amazon) are models I've used with great success. There are other models -- check Rob Crowe's JP1 forum.

Bill

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yes I looked at that page. I do have a JP1 compatible remote, but it is big and bulky and just not what I want.

The DVR is mainly used when anyone in my family is using the treadmill. I need a small remote with very few buttons. I want to be able to change the code with a micro controller.

If I don't find what I need, the source (radio Shack in Canada) has a One For All remote for only $10, but it is still not what I am looking for.

I attached a picture of the actual broken remote control.

Attachment(s): 

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heres one
http://www.beyondttl.com/irtx.php

pity its only got 5 buttons.