Sharp GP1U7?

[vttom]

Before I threw out an old VCR the other day I took it apart and yanked out the IR detector intending to use it for a PICAXE project.

Turns out the detector is the Sharp GP1U781R.

Has anyone used this detector with the Picaxe? I intend to use the infrain2 command on an 08M to interpret Sony code.


Incidentally, while researching this detector, and IR protocols in general, I found this program: http://www.ostan.cz/IR_protocol_analyzer/

I thought this sounded cool, so I hooked up the GP1U7 to a 5VDC supply and the output directly to a channel of the microphone input of my PC.

The analyzer does a great job of sampling the waveform and displaying it on the screen. However, it doesn't seem to recognize any of the protocols of any of my remotes (Sony or otherwise). I'm wondering if perhaps this detector does not quite behave the way the program expects? I also tried inverting the output of the GP1U7, and that didn't help.

Next step is to just hook it up to the PICAXE and run the infrain2 command and see if it detects anything.

 

[hippy]

Have a Google for the datasheet; turned up on first hit for me. This is a 38kHz sensor but may have a spread. It doesn't seem to need a pull-up but you could try. Not sure it's a good idea to connect directly to a Mic input as the device could put out 5V.

 

[westaust55]

By the part number it is a 38 kHz filtered unit.

That website you linked looks interesting.

The block diagram on the datasheet looks the same as many other 38 kHz IR detectors that folks here use so a good chance it will work with the PICAXE range of chips.

 

[Dippy]

Absolutely.

Your first task should ALWAYS be to get the device Data Sheet and compare it to known PICAXEable devices. And then to check that you can use it properly.

http://www.datasheetcatalog.org/datasheets2/38/38121_1.pdf
Have a read and check for yourself.



As said, it looks like most other low-cost IR modules.
Give it a go.

Well, if you are happy connecting to the 'mic' input that's up to you.
I'd have limited the o/p myself but there we are.
Maybe overloading or a decoupled input has messed up the signal so it can't be recognised properly.
Personally, I'd just stuff it onto my PICAXE like you would with any IR module - and give it a go.
After all, the module itself doesn't give a hoot about protocol as long as the carrier is OK.
The you can tell us if it is awesome and cool

 

[vttom]

Thanks for the input. I should've mention that I didn't connect the output directly to the mic input. I used a 10k Ohm resistor inline to limit the amount of current so that it wouldn't damage the mic pre-amp.

Also, I did look up the data sheet. Other than the block diagram it didn't really have a whole lot to say about how it behaved.

What I was looking for was a qualitative assessment that this thing is roughly equivalent to other IR detectors that people have used. I think that it is.

Thanks. I'll let you know how the infrain2 testing goes (won't get to that for a couple of days, tho).

 

[hippy]

In terms of every other IR receiver, as westaust55 says, looks about the same. Just read the input pin and see if it goes low when the remote is pressed before moving on to INFRAIN2. The output is transistor pulled-down so can probably even use a LED plus R, try with 1K-2K to keep the current low.