Do you want to get an early warning of brake failure while driving? Here is a brake failure indicator circuit that constantly monitors the condition of the brake and gives an audio-visual indication. When the brake is applied, the green LED blinks and the piezobuzzer beeps for around one second if the brake system is intact. If the brake fails, the red LED glows and the buzzer stops beeping. The circuit will work only in vehicles with negative grounding. It also gives an indication of brake switch failure.
In hydraulic brake systems of vehicles, a brake switch is mounted on the brake cylinder to operate the rear brake lamps. The brake switch is fluid-operated and doesn’t function if the fluid pressure drops due to leakage. The fluid leakage cannot be detected easily unless there is a severe pressure drop in the brake pedal. This circuit senses the chance of a brake failure by monitoring the brake switch and reminds you of the condition of the brake every time the brake is applied. The circuit uses an op-amp IC CA3140 (IC2) as voltage comparator and timer NE555 (IC3) in monostable configuration for alarm. Voltage comparator IC2 senses the voltage level across the brake switch. Its non-inverting input (pin 3) gets half the supply voltage through potential divider resistors R3 and R4 of 10 kilo-ohms each. The inverting input (pin 2) of IC2 is connected to the brake switch through diode D1, IC 7812 (IC1) and resistor R2. It receives a higher voltage when the brake is applied. Normally, when the brake is not applied, the output of IC2 remains high and the red LED (LED1) glows. The output of IC2 is fed to trigger pin 2 of the monostable through coupling capacitor C2. Resistor R1 is used for the input stability of IC2. IC1 and C1 provide a ripple-free regulated supply to the inverting input of IC2. IC3 is wired as a monostable to give pulse output of one second. Timing elements R7 and C4 make the output high for one second to activate the buzzer and LED2. Usually, the trigger pin of IC3 is high due to R6 and the buzzer and LED2 remain ‘off.’ When the brake pedal is pressed, pin 2 of IC2 gets a higher voltage from the brake switch and its output goes low to switch off the red LED. The low output of IC2 gives a short negative pulse to the monostable through C2 to trigger it. This activates the buzzer and LED2 to indicate that the brake system is working. When there is pressure drop in the brake system due to leakage, LED1 remains ‘on’ and the buzzer does not sound when the brake is applied. The circuit can be assembled on any general-purpose PCB or perforated board. Connect point A to that terminal of the brake switch which goes to the brake lamps. The circuit can be powered from the vehicle’s battery. The circuit requires well-regulated power supply to avoid unwanted triggering while the battery is charging from the dynamo. IC4, C6 and C7 provide regulated 12V to the circuit. The power supply should be taken from the ignition switch and the circuit ground should be clamped to the vehicle’s body. A bicolour LED can be used in place of LED1 and LED2 if desired.
Computers and the related technologies are becoming more and more ubiquitous.
Various technical arenas in the field of Computer Science and Engineering, or Information Technology have come very near to the common people. The number of homes with Personal Computers is gradually increasing. A day will come, somewhere in the long future, when PC is referred to in the same class of Food, clothing and shelter". Improvements in the Networking technologies have fostered growth of very dense networks. Land line telephones have been becoming less and less popular and people now prefer communicating while on the move.
A Remote Control is perhaps the most popular gadget today. Right from the intense creativity of remotely controlling laser chip markers to the highly destructive remotely ignitable bombs, from the pins to the planes, remote control is not only occupying a omnipresence state, but is also enhancing its scope and domains.
When people have a good connectivity at their disposal, with tremendous power of mobile computing to supplement the same, we can think of connecting their home appliances to the personal computer or a laptop". With this, people would be able to turn on and off, and to some extent, control the appliances at their home even from a distant place. One of the very basic examples of an utility of this is switching on the air conditioner in the room just some time before reaching home, so that the room is sufficiently cool by then.
The usefulness of a long range remote control to home appliances has no limits.
A trivial setup facilitating such a thing would be to connect the home appliances, to a microcontroller receiver antenna that receives the controls from the user, the means of sending the transmitted signals to the appliances may be via a circuit or through a wireless media like Infra Red or the RF, We have had Infra Red Remote Controls, which work over very short distances, and Radio Wave Remote Controls, which work over larger distances. However, something fundamentally common with all these controls is that the transmitter and receiver should both use some kind of wireless waves.
The project is an implementation to the idea of the wireless communication between a PC and a microcontroller.
The project deals with displaying this possible wireless communication by transferring message from PC to the LCD through wireless media.
We used Microcontroller unit (AT89C51), LCD s {Liquid Crystal Display}, LM7805 Regulator IC, resistors, capacitors, diodes, RF module. To write, test, simulate and debug the code, we used Kiel Complier and the programming was done in C language
Programmable number lock system is a high security number lock system that can be used to lock electronic devices. The present system is very user friendly. This system is a combination of software and hardware at its best. We have used a 8051 microcontroller kit for interfacing our system.
In the present design we can activate or deactivate 9 devices. Each device is locked using a 4 digit code (password). The code can be set as per the user’s desire, hence the name ' PROGRAMMABLE '. For the device to be activated (unlocked), the user should enter the code that had been entered when the device was locked. In case the user enters the wrong code a silent alarm will be activated.
Penelope is a small robot 25 cm high and 20 cm in diameter. I had built it in order to take part to a national microrobot competition which was held in
It is provided with:
- 5 sonars and 6 whiskers for obstacle avoidance
- 5 groups of directional light sensor, 3 directional microphones with 4kHz filters and one gas sensor for sources searching
- one compass and one odometer (=mileometer) for positioning
- two DC motors for moving
- one 12V lead battery for power supply
- one Motorola micro-controller M68HC11, mounted on the Motorola Evaluation Board (EVB) that provides the user with:
- one 8KB EPROM
- one 8KB RAM
- connection to a PC serial port for debugging
Robotic Car is a miniature prototype car powered by batteries whose various movements can be control either manually or automatically, or the combination of both. Here the command is given through keyboard; it would have been better if we used IR remote control or something of that kind rather than using keyboard for commanding. However, by realizing the complexities we have made simple using keyboard
The present concept implements controlling of pump which pumps water from the sump (underground tank) to the overhead tank, using 8951 microcontroller. 
The control panel, i.e. the main control unit of the system which consists of the primary control switches, pump indicator, siren and level indicators. The visual example of how switches And the indicators can be placed as shown the figure below.
In the figure shown above there are total of nine LEDs, four of which indicates the water level in the tank, another four indicates the water level in the sump and one LED indicates whether the pump is ON/OFF. It also consists of three switches.
Switch 1 is the main power switch which is used to activate the system.
Switch 2 is used to select whether to operate the pump in AUTO or MANUAL mode.
Switch 3 comes to picture only when the system is operated in MANUAL mode. It controls the direct activation of the pump.
We know that the railway network of
The idea is whenever any engine observes a red signal on its track it will start decreasing its speed gradually and stops automatically at some distance from the signal pole. After then when it gets green signal the driver can manually start the train and go on. In the mean time when train has not stopped yet and a red signal becomes green then it crosses the signal pole with low speed and then driver can slowly increase the speed.
So now before the driver observes the red signal the engine itself observes it and automatically starts decreasing speed and then stops. The driver can feel relax in driving because he doesn’t have to take care about red signal. Even if he forgets to take any action on red signal then also we can avoid accidents by the implementation of this idea
