Receive codes garbled after learn?

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Receive codes garbled after learn?

Postby jwnichls » Mon Oct 03, 2005 7:42 pm

I have noticed that the codes I get from the receive callback seem to be garbled after a learn. I am using the .NET wrapper in Visual C# .NET 2003.

For example, the "1" button on my VCR remote usually produces the following code from the receive callback:

631E000041F5

Then I perform a learn for the same button using the following call:

controller.Learn( CodeFormat.Uuirt, LearnCodeModifier.None, new TimeSpan( 0, 0, 0, 20, 0 ) )

Note that I wasn't sure what an appropriate timeout would be, so I set it very long for testing.

Immediately after the learn, I will get different codes from the receive callback for the "1" button. Usually the Usb-UIRT seems to recover within the receipt of a few codes, though occasionally it seems to take 25+ receives before it begins to receive the correct value constantly.

Is there a buffer that I need to flush after I perform a learn?

Thanks,

-Jeff
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Postby jrhees » Tue Oct 04, 2005 3:29 am

Hmmm, very strange.

Can you test a few things:

1. After Learn, move the remote at least 2 feet away and see if recovery is faster.

2. Please try using one of the sample apps that is *not* .Net-based and see if you can duplicate this.

3. See if this occurs with a different remote.

Thanks,

Jon
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Postby Guest » Fri Oct 07, 2005 3:25 am

Thanks for the response, John.

I continud playing around with my app, and I don't seem to be having this problem that often anymore. The main difference seems to be that I'm working in a different room, though it's not clear to me why that would change anything. Perhaps there was a lot of IR noise in that room? I've also had a bit more time to play around with the .NET wrapper, and it may just be that I'm dealing better with its quirks.

Now I have a new problem. I've gotten my app to work fine with most of the remotes that I have in my system, with the exception of the remote for my InFocus ScreenPlay television, which is the same as the RCA Scenium HDTV described in a different thread in the Troubleshooting forum. For this remote, I seem to quite often get different codes for the same button press. For example, for several presses of the "Input" button I got this sequence of codes:

678805051EF0
678805051EF0
3305051800F0
69070B0583F0
678805051EF0
678805051EF0

Note that this is just coming from the receive callback and I'm not doing any learning. Several particular codes appear often, usually in contiguous blocks, such as the 678xx code above. I've also seen the 3305xx code often, but all of these codes are interspersed with other seemingly random codes. The system definitely seems to report the same code more often when the button is pressed in rapid succession, but unfortunately that is not the usage scenario that I have for this remote.

There is one difference between this remote and my others, though I don't know if it is important. Unlike all of my other remotes, this one does not send a continuous stream of codes if you hold the button down. It seems to only send one code per button press.

Is there any way, perhaps computationally on the PC, that I can determine which of these codes are the same? I would try to record each of the codes that each button generates, but I fear that this would take a long time and might not be complete.

Thanks,

-Jeff


P.S. Right now, I'm trying to build an application that records all of the remote control activity for my home theater. Thus, I need to be able to recognize every button press on each of my remote controls.
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Postby jrhees » Fri Oct 07, 2005 11:42 am

Jeff,

Can you 'learn' one of the keys on that remote and post the learned code? That will give a clue as to what frequency and timing it is using.

Does distance/aiming have an effect on the % of 'random' codes?

-Jon
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Postby Guest » Wed Oct 19, 2005 1:47 am

I tried aiming the remote at different angles towards the UIRT and also varying the distance, but I get strange codes at about the same rate no matter how I change things.

This remote typically sends a burst instead of a continuous stream, but I was able to get a few learns without implementing the "Accept Burst" behavior that you describe in another thread. (At the moment, I don't believe it is possible to implement this behavior with the .NET wrapper, but I will look into it in more depth later tonight.)

This is what I learned for the "Input" button on the remote:

F2BR009C80E480E41D721C721C721C721C721C391C721C391C391D391D721C721C391C391C391C391D391C721D391C721C721D721C391C391C

This was a reliable learn, as I performed it several times and got the same result each time. The learn callback tells me that this is a 56.7Khz remote, which is what I've guessed from reading other sources on the Internet. I have the 56k version of the UIRT.

Another quick question, is it typical for the UIRT LED to periodically flicker when it is not receiving or transmitting any IR? My unit has always done this and I just assumed that it was normal, but perhaps not?

Thanks again!

-Jeff
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Postby Guest » Wed Oct 19, 2005 3:23 am

I was right that the .NET wrapper does not support the ability to accept bursts. I modified the wrapper to support this feature, and I've sent you the two source files that I modified via the support@usbuirt.com e-mail.

-Jeff
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Postby jrhees » Wed Oct 19, 2005 6:37 pm

Periodic flickering is an indication of other IR noise in the room. Two possilibites --

1) Noise from IR sources such as fluorescent lights, plasma tv's, sunlight, etc. As a test, try making your room dark and see if the randomness of codes changes or the flickering stops.

2) Noise may be from electrical/magnetic sources. As a test, try moving the USB-UIRT away from equipment. See if that has any effect. Also, if you happen to have a powered USB hub around, you may want to try plugging the USB-UIRT into it and see if it has an effect, in the event the USB power supply from your PC is unusually noisy.

Please let me know what you find!

-Jon
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VB. net code

Postby Claus » Mon Nov 14, 2005 10:08 pm

Jeff,

Any chance that you would be willing to let me see you VB .net code?

I am trying to build a custom remote apps myself, but I do not have the too much .net programming experience, so any examples I can get hold of is much appriciated.

Just in case, my email adr is claus@neesgaard.com

Thanks in advance,
Claus
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