I may be misunderstanding the description of your decoder circuit but it sounded like you have an IR detector (that's a Radio Shack part number, usually the companent part number is on the back of the cardboard packaging) hooked to the input of an op-amp and the output of that hooked up to in input of the 8051.

My first question is how comfortable are you that your circuitry is correct? I'm not an anlog guy but it sounds like unless you are taking care to slam the op-amp between rails, you may be presenting an analog voltage level to the 8051 input pin. That might explain some of the erratic input.

The best place to start for help (I'll be watching for your messages) is to identify the detector. With that, we may be able to suggest simpler interfaces. If you can create a GIF file of your circuit diagram (scan a diagram or use a microsoft tool to create an image) then you could email the file as an attachment. This forum doesn't facilitate diagrams.

Next question, how much time do you have until it is due? This isn't a trick question to find out if its a student project, you already appear to be attempting to solve it own your own. If you have a deadline, we'll try to be quick.

Tell us also about the crystal speed on your 8051. While the 8051 is certainly fast enough for most commercial IR remotes, you want to make sure its overly fast enough (has to do with Shannon's law).

Basic 52: That's one of the problems not using assembly language... you have to trust their documentation. Maybe someone else can answer that.

Question: Can you write or load assembly language into your 8051? If nothing else, this might be useful to test your circuitry and once proven, try Basic 52 again.

Is Basic 52 a compiler (hopefully) or an interpreter (less likely and if so slow).

aka j

If you want to email me some circuitry, send it to the following address and it will be forwarded to me:

sonabouy@yahoo.com

It sounds like a fun project. You might want to try the following experiment for fun. If you have a camcorder around, set it up to record or to display on a TV. Next take an IR remote and point it at the camcorder and press. What you will see appears to be a small light like that of a dim flashlight while the IR remote is sending. The reason the camcorder sees this and not your eyes is because the CCD detectors are sensitive over a wider range than the human eye. This includes IR light.

STORY TIME ENABLED
====================================
In fact, in our Tandy lab around 1985 we had in the lab a prototype model of a TV Phone (yeah, never manufactured it but it was fun). One day down the hall from my office, they were showing it to a Marketing guy and the engineers on that project were explaineing that the CCD camera could pick up wider light ranges than the human eye. The Marketing guy quickly realized that that meant that camcorder didn't need the heavy lights that were being sold with camcorders at the time. For low light operation, he correctly deduced, only required the camcorder have an IR Emitter to boost low light level recording. :)

The engineer that set him up for that great idea was annoyed for years that the Marketing guy got a patent for the company on that and he didn't think of it. heheheeheh. Tandy Marketing guys were the bain of the engineering department and it was a high insult to be patent bested by one. :)
====================================
STORY TIME DISABLED