手機來電指示器（英文）,Cellular Phone calling Detector

關鍵字：手機來電指示器,ne555

Flashes a LED when detecting an incoming call
Powered by one 1.5V cell

由一個1.5V電池供電，檢測到來電時LED閃爍

Circuit diagram 電路原理圖

Parts:
R1 100K 1/4W Resistor
R2 3K9 1/4W Resistor
R3 1M 1/4W Resistor
C1,C2 100nF 63V Polyester Capacitors
C3 220µF 25V Electrolytic Capacitor
D1 LED Red 10mm. Ultra-bright (see Notes)
D2 1N5819 40V 1A Schottky-barrier Diode (see Notes)
Q1 BC547 45V 100mA NPN Transistor
IC1 NE555 or 7555 or TS555CN CMos Timer IC  定時器芯片
L1 Sensor coil (see Notes)
B1 1.5V Battery (AA or AAA cell etc.)

Device purpose:
This circuit was designed to detect when a call is incoming in a cellular phone (even when the calling tone of the device is switched-off) by means of a flashing LED.
The device must be placed a few centimeters from the cellular phone, so its sensor coil L1 can detect the field emitted by the phone receiver during an incoming call.

Circuit operation:
The signal detected by the sensor coil is amplified by transistor Q1 and drives the monostable input pin of IC1. The IC's output voltage is doubled by C2 & D2 in order to drive the high-efficiency ultra-bright LED at a suitable peak-voltage.

Notes:
Stand-by current drawing is less than 200µA, therefore a power on/off switch is unnecessary.
Sensitivity of this circuit depends on the sensor coil type.
L1 can be made by winding 130 to 150 turns of 0.2 mm. enameled wire on a 5 cm. diameter former (e.g. a can). Remove the coil from the former and wind it with insulating tape, thus obtaining a stand-alone coil.
A commercial 10mH miniature inductor, usually sold in the form of a tiny rectangular plastic box, can be used satisfactorily but with lower sensitivity.
IC1 must be a CMos type: only these devices can safely operate at 1.5V supply or less.
Any Schottky-barrier type diode can be used in place of the 1N5819: the BAT46 type is a very good choice.

設備用途：
該電路設計用于通過閃爍的LED檢測蜂窩電話中的呼叫何時進入（即使設備的呼叫音被關閉）。
該設備必須放置在距離蜂窩電話幾厘米的位置，因此其傳感器線圈L1可以在來電期間檢測到電話接收器發出的場。
電路操作：
傳感器線圈檢測到的信號由晶體管Q1放大，并驅動IC1的單穩態輸入引腳。 IC的輸出電壓由C2和D2加倍，以便在合適的峰值電壓下驅動高效超高亮LED。
筆記：
待機電流消耗小于200μA，因此不需要電源開/關開關。
該電路的靈敏度取決于傳感器線圈類型。
L1可以通過纏繞130至150匝0.2mm來制造。漆包線5厘米。直徑成形器（例如罐頭）。從前者中取出線圈并用絕緣膠帶纏繞，從而獲得獨立線圈。
商用10mH微型電感器通常以微小矩形塑料盒的形式出售，可以令人滿意地使用，但靈敏度較低。
IC1必須是CMos類型：只有這些器件可以安全地以1.5V或更低的電源工作。
可以使用任何肖特基勢壘型二極管代替1N5819：BAT46型是一個非常好的選擇。