Automatic Bathroom Light

This is a circuit of automatic bathroom light which can be used to automate the working of a bathroom light. It is designed for a bathroom fitted with an automatic door-closer, where the manual verification of light status is difficult. The circuit also indicates whether the bathroom is occupied or not. The circuit uses only two  ICs and can be operated from a 5V supply. As it does not use any mechanical contacts it gives a reliable performance.

PC Based Wireless Stepper Motor control Circuit

Stepper motors find lots of applications in process control, machine tools and robotics. Especially in robotics and process control, bit is necessary to control the stepper motor from a remote place. Here you will get the transmitter and receiver circuit diagrams and Full source code for the application program.

Here we describe how to wirelessly control a stepper motor from a remote place by using RF modules. For this wireless stepper-motor control system, you need to design and develop the required hardware and software. The parallel port of the PC is used to control the direction of the stepper motor at the transmitter side. RF interface is used instead of IR to overcome all the drawbacks of the IR interface. The PC signals are transmitted from the RF transmitter and received by the RF receiver.

Seismic Sensor Circuit

This circuit is a very sensitive seismic sensor that detects vibrations/sounds. It can detect seismic vibration or sounds caused by animals or humans. So it can be used to monitor protected areas to restrict entry of unwanted persons or animals.

Laser Switch With Timer

This circuit is a laser controlled relay switch with timer that can be made using readily available components. This laser switch has the following advantages :

• Timed operation - Turn on time of the switch can be controlled
• Large current handling capability, can control a motor
• Stand by and operating mode led indication
• operating mode Piezo alert.

Servo Motor Tester Circuit

This circuit allows you to isolate the servo motor from the project circuit and feed it with pulses of varying width nd checking the angle that the servo motor turns to. the circuit is built using two NE555 IC's and a few discrete components. IC1 is set as an astable multivibrator with a time period of 20 ms. Every 20 ms, the astable provides a very sharp negative pulse to trigger IC2. Timer IC2 is configured as a monostable multivibrator that produces 1ms, 1.5ms and 2ms long pulses to rotate the servo motor (M1). 

Car Reverse Horn With Flasher

This is a circuit of car reversing horn with normal auto lamp flasher that uses timer ICs NE556 and NE555. When the car is in reverse gear, the switch S1 which is the reverse gear switch of the car get shorted and the monostable timer give a high output. So the diode D1 and D2 goes for high for a time period R4C4. 

Portable Electric Lamp cum LED Flasher

Here's the circuit of a portable type flasher uses 25W, 230V AC bulb and nine LEDs. The bulb and led's glows alternatively. The circuit includes a 555 timer based astable multivibrator which generates a square wave. This output drives the transistor bc547 to riger the gate of lamp controller triac.

Simple Duophone System

Here a simple circuit diagram of duophone that allows you to access two telephone line through a single telephone set. The conversation through each line will entirely private when the conference switch in the dual phone is off. So this duophone circuit has a unique feature of talking to two people simultaneously what is called three-party telephone conversation/conference facility.

Pyroelectric Fire Alarm

Ordinary fire alarm circuits uses diode sensors to detect fire presence. But a pyroelectric fire alarm circuit described here is an ultra-sensitive fire sensor that uses direct piezoelectric property of an ordinary piezo element to detect fire.

FM Booster Circuit to Receive Far Away FM Stations

This is a low cost FM booster circuit to receive far away fm stations clearly on your radio in your local area. The circuit diagram of FM booster consist of a common-emitter tuned RF preamplifier wired around VHF/UHF transistor 2SC2570.

Solar Charger Circuit For Lead acid, Ni-Cd And Li-ion Battery

The solar panel based charger described here is capable of charging Lead acid, Ni-Cd And Lithium-ion batteries. This circuit diagram is designed for a solar panel which is capable of delivering 5W power. The solar panel outputs 16.5V. It can deliver a current of 300-350 mA.lead acid, Ni-Cd and Li-ion. The lead-acid batteries are commonly used in emergency lamps and UPS.

LM317 Constant Current Battery Charger Circuit

The LM317 is an adjustable three-terminal positive-voltage regulator which can be used as a constant current source for battery charging. This regulator IC is capable of supplying 1.5 A over an output-voltage range of 1.25 V to 37 V.

Touch Sensitive Musical Bell With Timer

This circuit diagram is a UM66 based touch sensitive musical bell. The circuit is built around CMOS IC CD4011 and popular melody generator IC UM66. The circuit contains a pair of touch plates. When these are bridged by hand for a moment, the um66 starts making music. Moreover this circuit has a timer which stops the music automatically after a few seconds. This makes the circuit, an automatic music bell.

Computer Hardware Powerpoint Presentation

Here's a powerpoint presentation ppt about various computer harwares might useful for Engg./Diploma students. The presentation includes 52 slides and contains various tyspes of images and medias.

Powerpoint type : MS powerpoint 2003 (ppt)

Presentation Includes:

Rotation Sensor Circuit Using 555

The picture shows the circuit diagram of a rotation sensor that can turn on a device like motor or buzzer while the circuit assembly rotates. The circuit is based on basic 555 timer operation.

Simple Low Cost Digital Thermometer Circuit

The circuit diagram shows the simplest form of a digital thermometer which can measure temperatures up to 150°C with an accuracy of ±1°C. This digital thermometer circuit is of low cost because the reading portion of this equipment is done by a 1V full scale deflection digital voltmeter.