Discussion in "Project Doubts" started by    LeVisGuY    Mar 18, 2007.
Sun Mar 18 2007, 04:27 PM
Dear sir,

I would like to ask, is it possible for me to change the output, I mean the appliance section, the 5V to 12V? I'm worried that it might burn the microcontroller.

This is because, if i replace the LEDs and remove the resistors and replace with only a 5V relays, the relays does not work.

Sun Mar 18 2007, 07:50 PM
Dear sir,

i discover that, when I place relays into the circuit, directly taking the power from the output of the voltage regulator of 5V, the voltage keeps on dropping as I place in more relays.

The reason I use relays is to connect the circuit together with another RF circuit. I use the relays as a switch.

As I plug in the 3rd relay, the display on the LCD is already dim and the characters displayed is hardly readable. I measure the voltage output from the 7805 voltage regulator, it already drops to 4.11V with only 3 relays in the circuit, When I plug in 4 relays, the voltage drops till 3V plus and the voltage regulator is getting hot and hot but i do have a heatsink on it.

So, is there any method to solve my problem? If i would to use a trasistor for switching, 5V is way too much right? I might need to step down on the voltage. Other than transistors, what can I use to replace the relays or any other method to make the power supply stable as I plug in more relays?

Thank you.
Sun Mar 18 2007, 09:04 PM
ok.. here is a solution... use a optocoupler on the o/p side.. and connect the relays.. via optos.. or use relay driver.. ULN2003A
and you must not connect relays directly.. that can burn your microcontroller. the back EMF can destroy everything.. so connect a diode.. in opposite direction of the relay coil power.
and try using a high current DC adapter coz.. relay need high current.
Tue Mar 20 2007, 04:18 AM
Dear sir,

The Home Automation circuit, is it possible to take inputs into the controller and sends the data to the server.

If yes, may I know how to do?
Tue Mar 20 2007, 12:12 PM
yes of course it is possible... when you send stat command.. we are actually getting input from the relay circuit.. and sending back to server.

and.. for special input circuit.. you may use an opto coupler for getting the i/p of different voltage levels.
Thu Mar 22 2007, 11:46 AM
hello sir , u have almost completeing ur project !!! but can u help us sir ..
we just want to glow leds at the output first then we mayuse realy circuit .. is only leds are glowing
1 . forthat have u made anymodification in program or it is same as in the website .. can u plz send us the circuit did u made any modification ???
2 . from haserver giving command like tube , buld is the leds at the out put geting on and off
3 . have u interfaced lcds during testing at the output we are facing problem in lcd interfacing
can u plz help me and send the snap shot of ur circuit (lcd intefaced ) my email id is [email protected] .. please cooperate us .. we have downloaded a file in which u can get idea how to interface relay full deatl circuit diagram plz reply soon
Thu Mar 22 2007, 05:50 PM
i will provide you that.. later.. not now.. coz lil busy.. i can just give you some idea..
use ULN2803 search over internet.. get some idea regarding this.. and u can interface a real time 230V appliance with the help of relays

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