Detect light through serial or parallel ports

[crchisholm]

I have a need to detect light through the serial or parallel port of a computer. Here is the situation.

We have a server room that houses all of our servers, laptops and other expensive equipment. We want to know if anyone is in that room after hours. I would like to create a device that would use ether photoresisters or something like the tsl230 to change a value at the serial or parrallel port of a computer. We can write the app to monitor the ports and fire off an email if a signal is received, but I am not sure what I need to interface with the port. Does anyone feel like helping me with this. I am a software developer who is an electo-wanna-be and know only the most fundimental aspects of electronics.

Charlie

 

[Nigel Goodwin]

I have a need to detect light through the serial or parallel port of a computer. Here is the situation.

We have a server room that houses all of our servers, laptops and other expensive equipment. We want to know if anyone is in that room after hours. I would like to create a device that would use ether photoresisters or something like the tsl230 to change a value at the serial or parrallel port of a computer. We can write the app to monitor the ports and fire off an email if a signal is received, but I am not sure what I need to interface with the port. Does anyone feel like helping me with this. I am a software developer who is an electo-wanna-be and know only the most fundimental aspects of electronics.

Charlie

I would suggest a PIC, something like the 12F675 is only 8 pin, it could connect to the serial port and read an analogue value (10 bit if required) from your LDR. Then it could send that value to the serial port of your PC, it could also (if required) wait for such a request from the computer.

 

[crchisholm]

That sounds great. I have played with the basic stamp and the oopic, but never completed a project of any value.

Have you seen some example circuits that would help me put this together? I am extreemly green and doing this completely by trial and error would take a long time without any clues.

Thanks.

Charlie[/quote]

 

[Nigel Goodwin]

That sounds great. I have played with the basic stamp and the oopic, but never completed a project of any value.

Have you seen some example circuits that would help me put this together? I am extreemly green and doing this completely by trial and error would take a long time without any clues.

My tutorials include both serial routines and analogue input routines, they require very slight changes for the 12F675, but they are only slight.

 

[crchisholm]

I have been to your site and it looked like there is a lot of good info there. I clicked on the link you provide for the programmer and apparently it has been discontinued. I went directly to Microchips site and it appears that what I would need is the PICkit2 ...

**broken link removed**

and the MPLab ICD2 module (DV164005)...

**broken link removed**

Could you advise me on this? Is this the best way to start?

Once I have some hardware in my hands, I want o start going through your tutorials.

I did download your software, but at this point, I don't know if that's what I need, all that I need, or if I am completely round the bend.

Charlie

 

[Nigel Goodwin]

The ICD2 is far more versatile, and covers many more PIC's, but it is more expensive. You can buy (or make) cheaper ICD2 clones though!.