g1naveen
Posts: 5
Joined: Sun Dec 07, 2014 7:56 am
Location: India

RPi GPIO to Open & Close Car Doors

Sun Dec 07, 2014 8:39 am

I need help setting up Raspberry Pi Model B to control Car Door Lock unit(s).
I have connected my Rpi to a relay which looks like this :
gpio board.JPG
Gpio relay board
gpio board.JPG (27.14 KiB) Viewed 738 times
I wish to clarify what is NO, C, NC and how do they operate...
Here is the image of the door lock unit.
20141207135528.jpg
Car Door Lock Unit
20141207135528.jpg (51.07 KiB) Viewed 738 times
The 12V DC supply is needed for 1 second to lock and reverse connection for 1 second to unlock.
How to configure the pi to turnoff the relay in 1 second?
Should i connect the power supply out fom NC or NO?
Because when the relay power goes off, the lock should not open...
Any help would be deeply appreciated.

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rurwin
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Re: RPi GPIO to Open & Close Car Doors

Sun Dec 07, 2014 9:13 am

C -- Common
NO -- Normally Open
NC -- Normally Closed

In an unpowered state, the relay connects the common to the Normally Closed contact, ie it closes that contact and the NO contact is open.
When the relay is switched on, it instead connects the common to the Normally Open contact, ie it closes that contact and the NC contact is open.

So if you need current flowing when the Pi is not powered, then you should use the NC contact. Switching the GPIO on will stop the current flowing.
Whereas if you need no current flowing when the Pi is off, then use the NO contact. Switching the GPIO on will turn the current on.

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