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My project is SMS based device control in this i'm able to control devices through relays but when a person is at home he must be able to control the devices manually (through switch), when switch is turned off the state should be reflected to remote user (SMS sender)
Is this possible ??
When is interface buzzer in this way
The Buzzer is working properly
But when i interface it in this way
It is not working Why ?
The first three input pins of ULN2003 are connected to three relays ans they are working properly without any problem
Thanks everyone for replying
Its not working for me but when i interface it with two 1k resistors and one general purpose transistor its working but i can't understand why it is not working with
ULN2003 please help me.
I forgot to say one thing in my PCB that i used a insulated wire of about 8cm long from 7812 (present at one end of PCB) output (VREG) to the another end where 3 Relays, 100uf and 0.1uf capacitor are present
Is this causing any problem ??
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Thanks for your reply,
Yes they are AC Lamps !
---------- Post added at 21:18 ---------- Previous post was at 20:57 ----------
Yes it is actually AT89S52 Which need pullup Register across Port0 i used it in my PCB ( but not shown in circuit diagram )
---------- Post added at 21:26...
I tested my program on development board and it worked without any problems
---------- Post added at 18:47 ---------- Previous post was at 18:45 ----------
I am just switching 10 Watt - 15 Watt Bulbs
I am attaching the circuit diagram of my project
Serial Communication (MAX232) and LCD are working perfectly
i have so many doubts regarding my circuit
1) is 12v 1 amp transformer is sufficient to drive 3 relays using uln 2003
2) is it mandatory to ground the un used pins of uln 2003
3) in terms...
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