My Circuit

This cell phone detector circuit can sense the presence of an activated mobile cell phone from a distance of one and-a-half meters. If a RF signal is detected the circuit will inform you using a sound alarm (beep sound ) and a blinking LED . In this type of circuit (that use high frequency 0.9-3Ghz ) you can not use an LC circuit for frequency tuning  . The circuit uses a 0.22μF disk capacitor (C3) to according the RF circuit to ensure the capability of the circuit to capture the mobile phone signal . This cellular phone detector can detect any activity of a mobile phone : incoming or outgoing SMS , video transmission or voice transmission . The C3 capacitor must have leads length of 18 mm with 8 mm spacing between leads to obtain the desired frequency .  This small disk capacitor acts as a small gigahertz loop antenna to collect the RF signals  . The CA3130 operational amplifier IC is used as a current to voltage converter . This cellular phone detector electronic circ...

Using the RE46C140 circuit can be designed a very simple smoke detector alarm using few external electronic components . The RE46C140 IC is a low power CMOS photoelectric type smoke detector IC that will provide all the required features for a photoelectric type smoke detector project . This smoke detector alarm design incorporates a gain selectable photo amplifier for use with an infrared emitter detector pair. An internal oscillator strobes power to the smoke detection circuitry for 100us every 10 seconds to keep standby current to a minimum. If smoke is sensed the detection rate is increased to verify an alarm condition. Smoke Detector Alarm Circuit Diagram An interconnect pin allows multiple detectors to be connected such that when one units alarms, all units will sound. In standby the LED is pulsed on for 10mS every 43 seconds . In a local alarm condition or the push to test alarm the LED pulse frequency is increased to once every 5 seconds. In the case of a remote alarm the LED n...

Detect the presence of fire in the world of electronics can be done by detecting changes in temperature, the presence of UV ultraviolet rays and infrared light IR. Heat Sensor pyroelectric detectors Eltec E442-3 is a heat sensor (fire) that detect the presence of infrared ray IR, and therefore often called IR-EYE. These sensors form of Lithium Tantalate pyroelectric parallel opposed dual element high gain detector with integrated analog signal processing. These sensors can detect heat changes from -40 to +70 degrees Celsius without change siginfikan of noise and sensitivity. To use heat sensor pyroelectric detectors Eltec E442-3, it can take a kind of cone is covered with a fresnel lens to focus the direction of the infrared ray IR. Heat sensors then pyroelectric detectors Eltec E442-3 inserted into the cone is then connected to the microcontroller. Analog output value signals which when detects heat, the sensor will cause a drastic change in output voltage.

This is a very simple liquid detector which controls a relay, this gives you the option to be used for hundreds of applications. You can use it as a float switch to turn on the water pump alarm, rain, etc.. He uses a 4093 IC and transistor can be anyone, provided that it meets the power relay. This sensorcan be used with Arduino no problem . Sensor and Detector Liquids Circuit Diagram

A very simple heat detector alarm electronic project can be designed using the UM3561 sound generator circuit and some other common electronic parts . This heat detector electronic circuit project uses a complementary pair comprising npn and pnp transistor to detect heat Collector of T1 transistor is connected to the base of the T2 transistor , while the collector of T2 transistor is connected to RL1 relay T3 and T4 transistors connected in darlington configuration are used to amplify the audio signal from the UM3561 ic. When the temperature close to the T1 transistor is hot , the resistance to the emitter –collector goes low and it starts conducting . In same time T2 transistor conducts , because its base is connected to the collector of T1 transistor and the RL1 relay energized and switches on the siren which produce a fire engine alarm sound. This electronic circuit project must be powered from a 6 volts DC power supply , but the UM3561 IC is powered using a 3 volt zener diode , bec...

This is the Simple Resistance ratio Detector Circuit Diagram.  Photoelectric control, temperature detection and moisture sensing require a circuit that can accurately detect a given resistance ratio. A simple technique that uses an op amp as a sensing element can provide 0,5% accuracy with low parts cost. The reed-relay contacts close when the resistance of the sensor Rp equals 47% of the standard Rs.  Simple Resistance ratio Detector Circuit Diagram Adjusting either Rl or R2 provides a variable threshold; the threshold is controlled by varying R3. For the most part, the type of resistors used for Rl and R2 determines the accuracy and stability of the circuit. With metal-film resistors, less than 0.5% change in ratio sensing occurs over the commercial temperature range (0 to 70 C) with ac input variations from 105 to 135 V.

This causes the resistance of LDR to increase and the voltage at the base of the transistor is pulled high due to which the supply to the COB (chip-on-board) is completed. The sensitivity of the smoke detector depends on the distance between bulb and LDR as well as setting of preset VR1. Thus by placing the bulb and the LDR at appropriate distances, one may vary preset VR1 to get optimum sensitivity. We have not build this smoke alarm detector. For smoke detector installation and maintenance use a near electrician.

This circuit have applied to line detection of robot project, Good match between the transmitter and the detector is important for proper operation, especially if the hole is large. Infrared Emitter & Detector Circuit Diagram:   Robot with a simple object or obstacle detection. Infrared Transmitter detector pair sensors are relatively easy to implement, although involved some degree of testing and calibration in order to make correct. They can for the impediment, motion detection, transmitters, encoders are used, and the color detection. This can be done with a piece of rope stretched between and in accordance with LED and phototransistor. A length of stiff wire or plugs can be used to set the alignment. Another method that can be used for long distances is a laser pointer shone through a hole. Source / detector alignment method The transmitter can be mounted above the track with the phototransistor placed between the rails in places like hidden deposits. Place the transmitter ...

Since his letter-box is outdoors  and quite some way from the  house, the author was looking  for a simple means of knowing if  the postman had been without  having to go outside (contrary  to popular belief, the weather  isn’t always fine in the South of  France). Circuits for this kind of  ‘remote detection’ come up regularly, but always involve running cables between the letter- box and the detection circuit in  the house. Seeking to avoid running any extra cables, the author  had the idea of using the existing cables going to the doorbell,  conveniently located adjacent to  his letter-box.   The letter-box has two doors:  one  on  the  street  side  for  the  postman, and one on the gar-den side for collecting the post.  A  micro switch  is  fitted  to  the  street-side door, to light an indicator in the house showing that  the postma...

Detect the presence of fire in the world of electronics can be done by detecting changes in temperature, the presence of UV ultraviolet rays and infrared light IR. Heat Sensor pyroelectric detectors Eltec E442-3 is a heat sensor (fire) that detect the presence of infrared ray IR, and therefore often called IR-EYE. These sensors form of Lithium Tantalate pyroelectric parallel opposed dual element high gain detector with integrated analog signal processing. These sensors can detect heat changes from -40 to +70 degrees Celsius without change siginfikan of noise and sensitivity. To use heat sensor pyroelectric detectors Eltec E442-3, it can take a kind of cone is covered with a fresnel lens to focus the direction of the infrared ray IR. Heat sensors then pyroelectric detectors Eltec E442-3 inserted into the cone is then connected to the microcontroller. Analog output value signals which when detects heat, the sensor will cause a drastic change in output voltage.

NE555 Operation The NE555 comprises 23 transistors, two diodes 16 and resistors which form four elements: two operational amplifiers Compare type; an inverter logic gate; SET and RESET latch. The NE555 can operate in three modes: monostable, astable or bistable. I will detail precisely two in this article, the third being extremely simple. Astable operation For me, this is the simplest operation. This configuration allows to use the 555 as oscillator which will generate a square wave signal at its output. The astable word means that the timer has no stable state. The resistors Ra and Rb and capacitor C can modify the oscillation frequency and cylique report (have a look on the net if you want to know what these terms, they are important enough to the operation of this IC) . A complete oscillation is performed when the capacitor charges to 2/3 Vcc and discharged at 1/3 Vcc (voltage applied to the input of 555). During charging, the resistors Ra and Rb are in series with the capacitor, b...

In single phase AC induction motors, often used in fridges and washing machines, a start winding is used during the starting phase. When the motor has reached a certain speed, this winding is turned off again. The start winding is slightly out of phase to the run winding. The motor will only start turning when the current through this winding is out of phase to that of the run winding. The phase difference is normally provided by placing a capacitor of several µF in series with the start winding. When the motor reaches a minimum speed, a centrifugal switch turns off the start winding. The circuit diagram doesn’t show a centrifugal switch; instead it has a triac that is turned on during the staring phase. For clarity, the series capacitor isn’t shown in the diagram. Once the motor turns it will continue to do so as long as it isn’t loaded too much. When it has to drive too heavy a load it will almost certainly stall. A large current starts to flow (as the motor no longer generates a bac...