hi guys ,
I have found a ckt on ezone that can help us control electronc appliances using a pc.....it says that it can be done by controlling the parallel port of the pc .......anyone pls tell me the merits and demerits of the ckt....the link below has the full details of the project......http://www.electronic-circuits-diagr...tersckt1.shtml

 

hi,
The circuit should work OK, I see they also provide the program for the PC.

If your PC, OS is Windows XP you may require to download one or two *.dll's
in order to control the parallel port.

BTW, that image you have posted contains a cookie!

 

mr.gibbs if have tried this before can u give me the details of ur project

 

I have a number of projects that I can be controlled via the PC's parallel port.

What devices do you want to control?

 

*****
hello sirs,
Im a graduating student, and our group have this for our final project. Although, its not really the exact copycat because we are using required to use PIC on in, and one of my instructors said that we must also be able to control the devices by a manual switch. We are using the serial port to send data to the PIC.
Now I have this idea of using a keypad for the manual manipulation of the devices. The manual switch is a need because we will be using a LAN connection, and its (the manual switch) an advantage if the server is down.
See, the concept is to monitor and control the aplliances of a small building.

And then my question(s)
Whats the advantage of using RS232 over RS485, we only have to present
minuture of the whole system.

Can anyone of you give us idea how to put up the manual switch?
Can we use a keypad for this( the switch)? Were controlling atleast 4 devices
in each room.

Our group is composed of 3 female seniors and we only have less than 4 months to accomplish this. I would appreciate your suggestions...

 

generally ...as per the project that is given above power supply to any device can be controlled using the relay....i wanna use this circuit to control any device by controlling its powersupply

 

 

hi,
As it required to operate the relay for your device, why dont you use the circuit you have posted?

 

i want to use the circuit that I have posted ....but i wanna know if the circuit is tested by someone else ...can u tell me if this circuit works fine .....and also pls tell me list of dll files needed to download to allow windows xp to configure the printer port

 

hi,
As I said, the circuit looks OK.

The two dll's I would get are:
INPOUT32.DLL and DLLPORT.DLL

Eric

 

thanks for the concern .......and one more thing is there any chance of my computer being spoiiled because of hign voltage or any thing like that

 

No the printer port is isolated by the OPTOCOUPLER so it’s separating the relay drive circuit.

For a small load a small Relay will be ok but for a large load you must choose a big Relay according to the current drawn by the AC mains.

Also don’t forget to put the Back EMF protecting diode.

__________________
Gayan

My Website
http://gsmicro.blogspot.com/

 

hi,
If you want to test your PC's parallel port control, without the complete circuit, make the circuit marked in
RED.
If you have a meter you could measure the Voltage on the output pin, about +0.4Vlo and +4Vhi.

Do you have a port test program?

Have attached a zipped test program, exe and source.
You require the free Visual Basic runtime files, from the web, to run the *.exe

 

mr.gibbs can u tell me if i can use an 150ohm relay in lieu of the mentioned 100ohm ....and when i tried measuring the voltage across the parallel port it showed a value of 4.5volts all the time there is no change in voltage

 

gayan ....can i use a 150 ohm relay if i want to light up a 60watt bulb