Greetings and question

[billbo]

Hi,

I’m a complete beginner at electronics and as such even some of the suggested links to beginners pages have been too advanced for me. At this point I’d just like to be able to verbally communicate a query I have.

I’d like to know how you describe the process when you press a car key fob and it makes a noise (or any similar device – I’m not interested in anything specific to do with locks, alarms or cars etc.)

So like – the remote control(?) send radio waves which are picked up by a receiver(?) which triggers an amp(?) to give off a specified noise….

Something like that perhaps? Try and go easy on me if it’s way off, I promise I’m not a student looking to get my assignment done. I’ve looked around for other forums, they just didn’t seem as helpful or active.

 

[blueroomelectronics]

I suggest you start with basic electricity. Search for electrical tutorials and understand the basics before you attempt RF or remote control.

 

[billbo]

Ok. Will do, thanks for responding

 

[crutschow]

To answer your specific question, yes the car remote sends out a coded RF wave which is picked up by an RF receiver in the car. The RF receiver decodes the signal and sends out the appropriate control signal to the car's doors, lights, horn, etc.

 

[davidbball13]

try this for fun. give you car keys to a friend have him go a few blocks away. you call him and have him press the emergency button......give it a try

 

[Hero999]

There was a myth surrounding mobile phones and keyfob car alarm remotes awhile ago.

Some people thought that the moble phone would boost the signal so you could unlock your car from a couple of miles away. I hope you're not perpetuating that myth david.

 

[billbo]

Hmm, if there was a way of sending a signal perhaps to your carphone when a thief has just made off with your car, ooh lets see - jam brakes and release seat belt, that may be more interesting....

Hey crutschow thankyou for your response, it was helpful. Can you tell me what the particular component is that makes the noise?

thanks

 

[blueroomelectronics]

Commercial systems like LoJack do exactly that. They use a cellular modem to send an alarm and GPS location to their tracking office. The cops use a similar system to bait car thieves and they can control the engine cutoff.

If short range is all you need then you can buy short range RF TX/RX pairs plus the alarm and buzzer circuitry.

For long range you'd need a cell modem and that comes with monthly fees.

 

[billbo]

That's certainly interesting but i should reiterate i'm really just looking at the process involved with any product where you use a fob to give off a sound in another object, but thanks for your response.