Help neede please

M

Marchant

New Member

• Apr 29, 2010

• #1

I have built a sms controller. It is really a great project and it works excellent.
I want to put it in my car, for when my car alarm goes off, the sms controller must sms me.
The problem that I have now is how to use the siren output to trigger the sms controller input.
I thought of using the siren output, but the problem is every time I activate or deactivate the alarm I receive a sms. I need a type of time delay circuit, so that if the siren go on for say about more then 5 seconds, the sms controller must be activated.
Hope you guys understand what I am trying to ask.

 

StudentSA

Member

• Apr 29, 2010

• #2

I would like to know more about your sms controller?

 

StudentSA

Member

• Apr 29, 2010

• #3

Also to assist with your problem, can you please specify how the trigger of the sms controller works? Is it triggered on high or low level transistion?

 

M

Marchant

New Member

• Apr 29, 2010

• #4

The sms controller i got the plans from the EPE magazine that I get every month. The plans is olso on the net.
The controller has 8 inputs and 4 outputs. The inputs work between 3V and 12V. If it get that voltage it sms a pre defined sms to your mobile.
If you are interested in building the controller, I can e-mail you the plans.

 

StudentSA

Member

• Apr 29, 2010

• #5

I also get EPE at my office library, which month issue is the sms controller in?

Okay, to assist you, I can suggest that you use a 555 in monostable with a short output pulse. Use this to drive a simple 2N2222(or any NPN) transistor as a switch use the transistor to charge a capacitor through a resistor. By choosing suitable values you can cause the cap to charge slowly, i.e 0V... 0.2V ... 0.5V ... 1V etc till it reaches above 3V. This will only happen if the alarm has been on (triggering the 555) for awhile.

Alternativly you can search for the alarm box and use a multimeter to see which terminal is controlling the alarm.

 

M

Marchant

New Member

• Apr 29, 2010

• #6

Thank you very much for the info. I will definitely try that over the weekend.
The issues is 03-2007 and 04-2007.
I bought all the parts and edged the board as indicated in the mag. Build it and it worked first time. You will also need a Nokia 5110 and data cable. I made a data cable from plans from the net, worked fine.

 

StudentSA

Member

• Apr 29, 2010

• #7

Something like this ....



The charging of the capacitor is controlled by time constant RC.

R * C is the time it will take to charge to about 66% of Supply Voltage

 

M

Marchant

New Member

• Apr 29, 2010

• #8

How can I make a Monostable circuit with a digital input and not manual

 

StudentSA

Member

• Apr 29, 2010

• #9

im not understanding...

 

M

Marchant

New Member

• Apr 29, 2010

• #10

Sorry. The monostable circuits that I get on the net is all with a manual switch. I am not sure how to connect the siren to is.

 

StudentSA

Member

• Apr 29, 2010

• #11

To design the 555 timer please make referance to the Datasheet, can be found at Datasheet catalog for integrated circuits, diodes, triacs, and other semiconductors, view search for NE555 and look at the ST version.
The siren has two wires a positive and ground wire... just connect the positive to the trigger pin of the 555 timer.