Theft preventer alarm

This circuit utilising a 555 timer IC can be used as an alarm system to prevent the theft of your luggage, burglars breaking into your house etc. The alarms goes ON when a thin wire, usually as thin as a hair is broken.

The circuit is straightforward. It uses a 555 IC wired as an astable multivibrator to produce a tone of frequency of about 1kHz which gives out a shrill noise to scare away the burglar.

The wire used to set off the alarm can be made of a thin copper wire like SWG 36 or higher.
You can even use single strands of copper form a power cable.

The circuit operates on a wide range of voltages from 5V to 15V.

The speaker and the circuit could be housed inside a tin can with holes drilled on the speaker side for the sound to come out.

Rangkaian yang menggunakan IC timer 555 ini dapat digunakan sebagai alarm untuk mencegah pencuri menggondol barang-barang atau masuk ke rumah Anda. Alarm akan menyala (ON) ketika kawat tipis (biasanya setipis rambut) putus.

Rangkaian ini menggunakan IC 555 yang dikawati menjadi multivibrator yang tidak stabil untuk menghasilkan frekuensi sekitar 1 kHz yang terdengar cukup menakutkan perampok.

Kabel tipis yang dimaksudkan untuk mematikan alarm dapat dibuat dari kawat tembaga tipis seperti SWG 36 atau bisa juga serat kawat tembaga dari kabel power.

Rangkaian ini beroperasi dalam jangkauan tegangan yang cukup besar yaitu antara 5 hingga 15 V.

Speaker dan rangkaian dapat dimasukkan ke dalam kaleng dengan diberi lubang di depan speaker agar suara bisa keluar.

http://www.electronic-circuits-diagrams.com/alarmsimages/alarmsckt3.shtml

Infrared Head Phones

Using this low-cost project one can reproduce audio from TV without disturbing others. It does not use any wire connection between TV and headphones. In place of a pair of wires, it uses invisible infrared light to transmit audio signals from TV to headphones. Without using any lens, a range of up to 6 metres is possible. Range can be extended by using lenses and reflectors with IR sensors comprising transmitters and receivers.

IR transmitter uses two-stage transistor amplifier to drive two series-connected IR LEDs. An audio output transformer is used (in reverse) to couple audio output from TV to the IR transmitter. Transistors T1 and T2 amplify the audio signals received from TV through the audio transformer. Low-impedance output windings (lower gauge or thicker wires) are used for connection to TV side while high-impedance windings are connected to IR transmitter. This IR transmitter can be powered from a 9-volt mains adapter or battery. Red LED1 in transmitter circuit functions as a zener diode (0.65V) as well as supply-on indicator.

IR receiver uses 3-stage transistor amplifier. The first two transistors (T4 and T5) form audio signal amplifier while the third transistor T6 is used to drive a headphone. Adjust potmeter VR2 for max. clarity. Direct photo-transistor towards IR LEDs of transmitter for max. range. A 9-volt battery can be used with receiver for portable operation.




http://www.electronic-circuits-diagrams.com/audioimages/audiockt3.shtml

Car Wireless Alarm

Looking for wireless alarm for your car ?

This FM radio-controlled anti- theft alarm can be used with any vehicle having 6- to 12-volt DC supply system. The mini VHF, FM transmitter is fitted in the vehicle at night when it is parked in the car porch or car park.

The receiver unit with CXA1019, a single IC-based FM radio module, which is freely available in the market at reasonable rate, is kept inside. Receiver is tuned to the transmitter's frequency. When the transmitter is on and the signals are being received by FM radio receiver, no hissing noise is available at the output of receiver. Thus transistor T2 (BC548) does not conduct. This results in the relay driver transistor T3 getting its forward base bias via 10k resistor R5 and the relay gets energised.

When an intruder tries to drive the car and takes it a few metres away from the car porch, the radio link between the car (transmitter) and alarm (receiver) is broken. As a result FM radio module gene-rates hissing noise. Hissing AC signals are coupled to relay switching circ- uit via audio transformer. These AC signals are rectified and filtered by diode D1 and capacitor C8, and the resulting positive DC voltage provides a forward bias to transistor T2. Thus transistor T2 conducts, and it pulls the base of relay driver transistor T3 to ground level. The relay thus gets de-activated and the alarm connected via N/C contacts of relay is switched on.

If, by chance, the intruder finds out about the wireless alarm and disconnects the transmitter from battery, still remote alarm remains activated because in the absence of signal, the receiver continues to produce hissing noise at its output. So the burglar alarm is fool-proof and highly reliable.

Schematic



http://www.electronic-circuits-diagrams.com/alarmsimages/alarmsckt12.shtml

12V - 40W Fluorescent Lamp

Lampu Neon 12 V - 40 W

If you don't satisfied with the 12VDC Fluorescent Lamp and wanna build the larger one, you can make this.

This 40W fluorescent lamp inverter allows you to run 40W fluorescent tubes from any 12V source capable of delivering 3A and can be used to light regular or blacklight tubes.

Schematic

Parts

Part	Total Qty.	Description	Substitutions
R1	1	180 Ohm 1W Resistor
R2	1	47 Ohm 1/4W Resistor
R3	1	2.2 Ohm 1W Resistor (only needed once)
C1, C2	2	100uF 16V Electrolytic Capacitor
C3	1	100nF Ceramic Disc Capacitor
Q1	1	TIP 3055 or 2N3055 or equivalent
L1	1	See "Notes"
T1	1	See "Notes"
MISC	1	Wire, Case, Board, Heatsink For Q1, heatshrink, AM antenna rod for coil

Notes

1. Email Bart Milnes with questions, comments, etc.
2. Wind L1/T1. You will need an AM antenna rod that is about 60mm (2.5 inches) long to wind T1/L1 on. T1/L1 are wound on the same core. Shrink a layer of heatshrink over the core to insulate it. Leave 50mm of wire at each end of the coils.
   Primary: Wind 60 turns of 1mm diameter enamelled copper wire on the first layer and put a layer of heatshrink over it.
   Feedback: Wind 13 turns of 0.4mm enamelled copper wire on the core and then heatshrink over that.
   Secondary: This coil has 450 turns of 0.4mm enamelled copper wire in three layers. Wind one layer and then heatshrink over it. Do the same for the next two.
   
3. Calibrate/test the circuit. To calibrate/set up the circuit connect the 2.2 Ohm 1W resistor (R3) in series with the positive supply. Connect a 40W fluorescent tube to the high voltage ends of the transformer. Momentarily connect power. If the tube doesn't light immediately reverse the connections of L1. If the tube still doesn't work, check all connections. When you get the tube to light remove the 2.2 ohm resistor and the circuit is ready for use. You will not need R3 again.
4. This circuit is designed for 220V lamps. It will work with 120V units just fine, but will shorten the life of the tube.
5. This page has been extensively rewritten by Bart Milne. (15/3/01)

Jika Anda kurang puas dengan lampu neon 12 VDC dan ingin membuat yang dayanya lebih besar, Anda bisa membuat yang satu ini.

Inverter lampu neon 40 W ini bisa menyalakan lampu neon 40 W hanya dengan power suplai 12 V berarus 3 A, bisa neon biasa atau neon tabung hitam.

Catatan:

1. 
   

12VDC Fluorescent Lamp

Lampu Neon 12 V DC

If you are looking for Fluorescent Lamp Driver using ordinary transformer, here it is.
It uses a normal 120 to 6V stepdown transformer in reverse to step 12V to about 350V to drive a lamp without the need to warm the filaments.

Schematic

Parts

Part	Total Qty.	Description	Substitutions
C1	1	100uf 25V Electrolytic Capacitor
C2,C3	2	0.01uf 25V Ceramic Disc Capacitor
C4	1	0.01uf 1KV Ceramic Disc Capacitor
R1	1	1K 1/4W Resistor
R2	1	2.7K 1/4W Resistor
Q1	1	IRF510 MOSFET
U1	1	TLC555 Timer IC
T1	1	6V 300mA Transformer
LAMP	1	4W Fluorescent Lamp
MISC	1	Board, Wire, Heatsink For Q1

Notes:

1. Q1 must be installed on a heat sink.
2. A 240V to 10V transformer will work better then the one in the parts list. The problem is that they are hard to find.
3. This circuit can give a nasty (but not too dangerous) shock. Be careful around the output leads.

Anda mencari rangkaian lampu neon 12 V DC dengan menggunakan trafo biasa? Ini dia.

Trafo yang digunakan seperti trafi biasa dengan tegangan 120 ke 6 V yang digunakan terbalik sehinggga dengan tegangan primer 12 V menghasilkan tegangan output 350 V untuk menyalakan lampu neon tanpa memanaskan filamen.

Catatan:

1. Q1 harus meenggunakan heatsink (peredam panas)
2. Lebih baik menggunakan trafo 240 ke 10 V, tapi masalahnya susah didapat :-)
3. Hati-hati dengan tegangan keluaran, bisa menyetrum!