Jump to content
Electronics-Lab.com Community

Car Burglar alarm


Recommended Posts

You could store the message on a ISDxxxx record/playback chip. Instead of triggering the relay forr the horn, you could send the pulse to this chip and have it play the message.
There seem to be a few of these chips with different numbers, so I replaced the number with xxxx.


Link to comment
Share on other sites

I made something like this once.
Here is how I did it. I bought a Tape that goes into an answering machine. It was a tape that has an endless loop. The one for the Greeting Message. I recorded my message with the answering machine. Then I installed a 12v car tape player under the dash board. I hooked the hot side to my Headlight switch and the negitive to the Dome light switch. When ever I opened the door with the headlights on it told me" You left your headlights on!" in my own voice.

Link to comment
Share on other sites

  • 3 weeks later...

i had the vision of building one of these babys before and it's been re kindled after watching the 2nd series of pheonix nights.. lol

Both using a tape and using a digital voice recorder are viable but as the tape decks are easy to come by and have a solenoid, magnetic reed switch, heads and the motor, it would be much more enjoyable to watch it work and it will bring you closer to understanding the fundementals of step by step electronic sequences

Using a 4017 cmos decade counter or two with this kind of project, will keep it simple and YOU will know every piece of logic going through your project.

Firstly think of what your project needs to do, in steps..

1>__"armed" use output '0' to hold the clock enable pin on the 4017 to ground this logic state could also supply power to your intruder sensor, if required.

2>__"Trigger".. Hold the clock enable pin to + momenteraly and the count begins on the next clock pulse.

3>__"cassette rewound"?. output '1' goes high, throw the motor into reverse for a few seconds or until no more pulses are recieved from the reed switch (this can be achieved using "initiation by supply" configaration of a 555 timer). this will tell your clock to start counting again or lift the clock enable pin high again.

4>__"Amplifier on" output 2 switches a relay that applies power to the amplifier.

5>__"Wait for reset" output 3 is connect via a 4148 diode to output 2 in such a way that output 2 still applies power to the amplifier

6>__"play message" output 3 also inhibits the clock of its own chip but allows the 2nd 4017's clock to enable. a 2 input and gate with the clock pulse on 1 of the inputs and the output from 3 on the other input would do the job of supplying a clock pulse to the 2nd 4017.

7>__"playing loop" the second 4017's output "0" is high on the next clock pulse output "1" is high this pin applies power to the solenoid and the motor (forward running)

8>__ on the next clock pulse output "2" goes high, this can be used to break current to the solenoid but keep the motor running.

9>__ the next bit depends on your clock frequency.. if your running at 1hz then each output of the 4017 will be high for 1 second therefore you can use upto 8 seconds by having all the other outputs holding the motor on (plenty of recording time to say "GET BACK YA BAS**RD, I'LL BRECK YA LEGS!!. However, the last output "9" needs to rewind the tape using the description in para 3.

there maybe problems over looked as this is the first time i've explained it so indepth, there are obviously shortcuts or design enhancements that can be made but these would be on the breadboard stage.

I also think your tutor maybe more impressed with the whole programming to wiring of this project. if LED's where added and labeled for each of the different inputs, outputs and inhibits of the components it would be a great training tool. Any probs then i'd be glad to assist.


Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Create New...