MINI TRACKER :-

                                      Mini Tracker is the result of many requests for a tracking device and brings a new world of tracking to your fingertips.
The circuit is very compact and consumes almost no power. It is small enough to be hidden in anything you suspect will be lost or stolen.
By using a mercury switch or grasshopper, the bug can be “primed" for the time when it is moved and you can track it with an FM radio.

DIAGRAM:-


                        

                                          The Mini Tracker transmits a very short burst of carrier which produces a blank spot on the FM dial - commonly called “silence.” Normally, a lot of background noise called “snow” is picked up by a radio when it is tuned to a frequency between the stations. The change between silence and snow produces a “click” or “beep” and this is the noise produced by the project. No actual “beep-tone” is produced - just a change in signal quality. The carrier (or silence) is emitted about twice a second.

CIRCUIT DIAGRAM:-


                         

PARTS LIST:-

• 1 - 220R
• 1 - 330R
• 2 - 1k
• 1 - 47k 
• 1 - 220k
• 1 - 5p6 ceramic
• 1 - 10p ceramic
• 1 - 39p ceramic
• 1 - 1n ceramic 
• 1 - 22n ceramic
• 1 - 10u 16v PC mount electro
• 1 - 22u 16v PC mount electro
• 2 - BC 547 transistors
• 1 - BC 557 transistor
• 1 - 5 turn, 3mm dia  enamelled wire 
• 3 - button cells
• 1 - battery box (PC board pieces)
• 1 - 80cm hook-up wire for antenna
• 1 - Mini Tracker PC BOARD

HOW THE CIRCUIT WORKS:-

                         The circuit consists of two building blocks - both are oscillators. The first operates at a very low rate (low frequency - about 2Hz) and the other operates at approx 90MHz. The first is a square-wave oscillator with a very short “ON time,” while the other is a sine-wave. The only thing they have in common is a “feedback component,” to create and maintain oscillation. In all other respects they are different. 
              The first block is a 2-transistor PULSE GENERATOR and the second is an RF OSCILLATOR.

                                        The first point we need to cover is the fact that the first "building block" is separated from the battery via a 1k resistor. This is very important as the Pulse Generator takes a very high current when it is "active." We say "high current" in relative terms as the whole circuit takes very little average current as it is active for very short bursts. But the current is high during the short bursts of operation and we need to check the current taken during the bursts, to make sure it is as low as possible.  
If the 1k resistor is removed, the Pulse Generator circuit would place a 220R across the battery and this would put a heavy load on the battery during the time when the RF oscillator is operating. 
This would represent "wasted power" and decrease rail voltage during the time when we need maximum output. To prevent this, we have separated the Pulse Generator circuit from the RF Oscillator with a 1k resistor. 

                                            ALL THE BEST.................////////////////////////