Hi.

I need to take input from some sensors, which will provide digital signal of TTL level. Each of them will be either On (High) or Off (Low). I don't want to use any Data Acquisition Card or Digital I/O card for it, instead I want to use the parallel port.

Each sensor will have its own battery for providing TTL level signal to the computer. When the sensor detects something it will turn its line On (high). Since the computer will be continuously polling the parallel port to see the status of the sensors, therefore this change will be detected by it.

What i need is a circuit that can enable me to connect these sensors to the parallel port. They are digital (either on or off) and have their own battery to generate TTL level signal for computer. There is no problem with the software side, I can do it. I'm just confused about this circuit. I highly appreciate any help from you. Thanks.

Regards.

 

B&B used to have something available called a PPIO. They may still sell it. I recommend starting your search there or just query the internet.

(8{)} ( .)

 

You can use C or C++ : just refer to Chapter 5 of BUILD YOUR OWN LOW-COST DATA ACQUISTION AND DISPLAY DEVICES, by Jeffery H. Johnson ($22)

A simpler reference is : CONTROLLING THE WORLD THROUGH YOUR PC.

You can also do this with VISUAL BASIC : Find the website of Prof. Arjan, of India, and download his public domain VBIO.DLL. Instructions on its use are included.

 

Hi, Mark

You gave too poor information to design what you want. First, what are the distances from your sensors to your PC? How many sensors do you have now and plan to add at the future? Do you like to have optical isolation PC from your sensors?
--
Best regards,
Mike mailto:[email protected]

 

This site has links to everything you need to know

"http://www.uct.on.ca/":http://www.uct.on.ca/

 

Hello,

I am looking for something like you, but I need the software.

I found a diagram "http://www.joethielen.com":http://www.joethielen.com and look for phantom security...

Could you mail me your parallel port checking software ? ( "[email protected]", mailto:[email protected] )

Thanks

Thomas

 

<p>simply connect a switch to any of the D0-D7 pins of the parallel port pins 18-25 to grnd. use turbo c.
<pre>
syntax:

variable = inp(0x378);

+5
|
330 ohms
|
D0 ______ switch_____|
</pre>
<p>just compare
<pre>
if (0x001 == inp(0x378))
{
printf ("signal");
}
</pre>

 

This diagram shown, does it need external power? Or does it get the power from the difference between the two pins? (D0-D7 to pins 18-25)