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# 1.5v relay?????

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##### New Member
What I am trying to do is build a device that will activate the remote start system on my truck with a pager. I have all the components except a relay with a 1.5v coil. I need to get a ground pulse to the remote start module to make things work. I thought that if I got 1.5v from the vibrator motor on the pager and ran it thru a relay to send a ground signal, that would do it. Problem is I'm having problems finding a 1.5v relay. Anyone know where to find something like this or a different way of doing this?

#### audioguru

##### Well-Known Member
The relay is mechanical. Therefore it uses a very high operating current.
Why not use a transistor to drive a normal 12V relay instead?

##### New Member
Forgive me in advance but I'm quite uneducated when it comes to this stuff. (Polite way of saying stupid). Could please advise on how to use the resistor to make a standard 12v relay work.

##### New Member
Bump. I've got the dash pulled out of my truck and was hoping to get this project completed before too long. How do I use a transistor to make this work?

#### House0Fwax

##### Member
Have a look here;

##### New Member
I've got diodes and resistors in the shop from the r/s installs. Just need to know what transistor to get and a "diagram for a dummy".

#### Diver300

##### Well-Known Member

That is what you want to be using. Vin and the switch on the left are replaced with the 1.5 V from the pager. The relay can be an ordinary automotive one. The diode can be just about any diode. 12V comes from the car battery, and is connected to the point labeled Vcc on the diagram.

You will need to look up which connection is which on the transistor that you bought. https://upload.wikimedia.org/wikipedia/commons/c/cb/BJT_NPN_symbol_(case).svg shows which the connection names (Emitter, Base and Collector or E, B, C)

The diode has to go the correct way round.

1.5 V from the pager (or an AA battery for testing) will make the relay operate.

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