Matt circuit

This is a simple PIC Security System Dials Your Cell Phone Circuit Diagram . Do-it-yourself phone dialer security system calls your cell phone, office etc. whenever a door or window is opened, or panic button is pressed. Great Home Alarm. PIC Security System Dials Your Cell Phone Circuit Diagram The circuit consists of a small PIC microcontroller, assembly program, and a few other parts to detect a switch closure from an open door, window, or manual push button and then dial the cell phone number, and transmit a steady tone to indicate the source of the call. The circuit uses the pulse dialing system to interrupt the line connection a number of times to indicate each digit. Pulse dialing (the oldest form of dialing) works by actually disconnecting or "hanging up" the phone line a number of times to indicate each digit. For example, the digit "5" would be dialed by disconnecting and reconnecting the line 5 times in short intervals of about 100mS. There is about a 1 s...

  The 555 can be LM,NE or MC(cmos) type.C1/C2's working voltage should be increased to 25V if you decide to go with a 12V power source. Rule of thumb: the working voltage of capacitors are at least double the supplied voltage, in other words, if the power source is 9Volt, your capacitor(s) is at least 18V.T1 can be any approximate substitute. But make sure that metal casing was not grounded. But as the schematic shows you can basically hook it up to any type of metal surface. I used a 12-vdc power source. Use any suitable relay to handle your requirements. A 'RESET' switch (Normally Closed) can be added between the positive and the 'arrow-with-the-+'. The trigger (touch) wire is connected to pin 2 of the 555 and will trigger the relay, using your body resistance, when touched. It is obvious that the 'touching' part has to be clean and makes good contact with the trigger wire. This particular circuit may not be suitable for all applications. Just in case you ...

The risks of installing your own auto sound system may be greater than you realize. The fact is that there are people that are professionally trained in the installation and proper handling of these delicate sound systems for a reason. If it weren't a difficult task they wouldn't be able to demand the rather hefty price tag that most installation centers charge. The problem is that mistakes can actually cost more than the installation. If you aren't one hundred percent certain that you can handle the installation process alone it is best to leave it up to the experts. To prove my point, I will give you my very own personal story of how auto sound system installations can go horribly (well, perhaps hilariously would be the better choice of words in my particular situation) of course. You see I wanted a CD player in my mini van about 13 years ago. This was back in the dark ages when these types of sound systems were still relatively new and on the 'cutting edge' when ...