Innovative Project Ideas

https://www.youtube.com/watch?v=yy6JcgBPuv8

Weekend Projects - Little Big Lamp Complete instructions for this episode of Weekend Projects can be found at http://makeprojects.com/Project/Little-Big-Lamp/2310/1 Combine your shop skills an...

https://youtu.be/oJIQFXno2vE

Smart Street Lighting System Summer Project by the students of VIT University, Vellore. The project aims at curbing the power losses in the street lamps during the night time. It is base...

Battery Charger Circuit Using SCR

The battery is charged with small amount of AC voltage or DC voltage. So if you want to charge your battery with AC source then should follow these steps, we need first limit the large AC voltage, need to filter the AC voltage to remove the noise, regulate and get the constant voltage and then give the resulting voltage to the battery for charging. Once charging is completed the circuit should automatically turned off.

The AC source is given to the step down transformer which converts the large AC source into limited AC source, filter the AC voltage and remove the noise and then give that voltage to the SCR where it will rectify the AC and give the resulting voltage to the battery for charging.

Circuit Diagram Explanation:

The AC main voltage is given to the step down transformer the voltage should be down to 20V approx. the step down voltage is given to the SCR for rectification and SCR rectifies AC main voltage. This rectified voltage is used to charge battery.

When the battery connecter to the charging circuit, the battery will not be dead completely and it will get discharged this will give the forward bias voltage to the transistor through the diode D2 and resistor R7 which will get turned on. When the transistor is turned on the SCR will get off.

When the battery voltage is dropped the forward bias will be decreased and transistor gets turned off. When the transistor is turned off automatically the diode D1 and resistor R3 will get the current to the gate of the SCR, this will triggers the SCR and gets conduct. SCR will rectifies the AC input voltage and give to the battery through Resistor R6.

This will charge the battery when the voltage drop in the battery decreases the forward bias current also gets increased to the transistor when the battery is completely charged the Transistor Q1 will be again turned on and turned off the SCR.

Auto Night Lamp Using High Power LED

Auto Night Lamp Using High Power LEDs is a circuit which turns ON the LED lights interfaced to it at night time and it turns OFF the lights automatically when it is day. Usage of LEDs is growing day by day due to the advantages they provide compared to the conventional filament bulbs or fluorescent lamps. They provide good quality of white light with a better intensity compared to others. They also consume less power compared to their alternatives. These are the advantages which the LEDs encourage us to use them compared to their alternatives.

In this article, we shall see the circuit and the working of turning on or off of high power LEDs with light intensity. The element which is used for sensing light in the circuit is the light dependent resistor. The resistance of the light dependent resistor depends on the light incident on it. If the intensity of light incident on it is more, then the resistance of the circuit decreases. If the intensity of light incident on it decreases, then the resistance of the device increases. We are making use of this property of the light dependent resistor to detect the light and thereby operate the LEDs. We are arranging twenty five light emitting diodes in an array such that five LEDs are in series and five such series LEDs are arranged in parallel.

The transistors are used in saturation mode. They are used as electronic switches in this mode. The transistor BC547 is a general purpose NPN transistor which is used to further switch the LEDs. This is a power transistor with a heat sink. The heat sink helps the transistor to dissipate the generated heat into air so that the transistor can handle higher power loads than it can do without the heat sink.

The entire circuit along with the LEDs is powered by a 12V DC power supply. A battery based DC power supply is usually preferred. However, you can use a ac rectified and regulated power supply.

The LEDs used in the circuit are high powered white LEDs. The intensity of light produced by these LEDs equals an ordinary fluorescent bulb. The lighting produced is sufficient for reading or to do any other daily activity. The circuit can be assembled on a printed circuit board with all the components neatly arranged and the LEDs placed in order. Try to place the LEDs maintaining a distance of about 1 cm between the LEDs so that the the lighting will be well distributed in your room.

IR Remote Control Switch

This circuit is low cost and can be constructed easily. By using this circuit, we can control any house hold appliance with the help of remote. In this project, there are two parts – one is in transmitting section and the other is in receiving section. Receiving section will be in a stable position which is connected to any load and transmitter will act as a normal remote.

Block Diagram Explanation:

The main function of this remote control switch is to control any load (TV, Radio, Stereo, Fan, Light, etc.). In this circuit, we are using one switch for operating the transmitter, with this we can switch on or off the TV, motor, radio or any other home appliances.
We can even control the volume of TV, radio and many more by adding extra circuitry to the actual circuit. Here in the transmitter section, we have NE555 timer which is configured in astable mode and infrared LEDs whose infrared rays are directed by the concave lens and the source of power is from 9V battery.
Switch in the circuit plays the key role in the transmitter circuit. When the switch is closed, the power from the battery turns on the NE555 timer which will act as an astable multivibrator. The infrared LEDs which are connected to the output of NE555 will get high and produce the infrared beam through the concave lens.
When the infrared beam from the transmitter is reached by the receiver section, the photo LEDs will receive the infrared beam and charge the capacitor which will increase the input voltage of one pin of operational amplifier and high output is generated. This high output is given to the 4018 Counter as input and counter will drive the load through a relay to switch on or switch off accordingly.
Infrared Remote Control Switch Circuit Components:

CA3130: CA3130 is a BiCMOS operational amplifier, which has very high input impedance, very low input current and high speed performance. It had very low input swing i.e. below 0.5V; the operating supply voltage is of around 5V to 16V. It will permit the output swing also. Maximum differential voltage between two inputs should be 8V. The main applications are they are used as single supply amplifiers, timers or monostable multivibrators, voltage followers and detectors, peak detectors etc. They can also be used in photodiode – a sensor amplifier that’s why we use this component in our circuit as amplifier.

CD4018: The main function of counter is to store (and sometimes displays) the number of times a particular event or process has occurred, often in relationship to a clock signal. CD4018 is the 16 pin counter in which there are 5 jam inputs (sets the counter to that number and sends the number out immediately. If the number is outside the minimum and maximum count range, this message is ignored), clock, data, preset, enable and reset pins. It had around 5 Johnson counter (twisted ring counter) in which output of the last stage is inverted back and given as input to the first stage. The main features are fully static operations, different noise margins at different voltages (1V noise margin is 5V), supply voltage ranges from 3V to 18V. Clock input frequency also varies at different supply voltage. 5V VDD will give around 3Mhz frequency. Counters are used in different applications like frequency division, counter control, programmable decade counter, minicomputer, etc.

Circuit Explanation:

In the receiver section there are 3 photodiodes which will detect the infrared signals from the receiver and produce leakage current to the capacitor C1. This current is given to the inverting input of 3130 IC which will get triggered by this current and give amplified output. Remaining all other pins are connected to the ground.
R2 and C2 are used to stop the unwanted signals from triggering the IC. C3 is used for high gain which is used as comparator amplifier.
The output of IC3130 is given to the pin14 CLK of Johnson counter 4018. The output of 4018 IC will go high by applying successive clock pulses.
The resistor R4 is used to stop loading the transistor. The transistor will get ON when the output of 4018 is high and drive the relay to operate in 12V. The diode D4 will protect the relay from reverse current.
The relay will switch ON or OFF the appliance that is connected to it. LED will act as a visual indicator and also stops the reverse voltage which will effect the counter.
In the transmitter section, the 555 timer is configured in astable mode and resistors R5, R6 and capacitor C6 are adjusted to give the 5Khz operating frequency.
When the switch is ON, the capacitor C6 will get charged and when the switch is OFF, it will be discharged through R6 and 555 timer internal transistors. When switch on the 555 timer, output pin3 will be high this will trigger the transistor SK100.
Resistor R7 is used to stop loading of transistor. When transistor is ON, the infrared diodes which are connected to it will produce high intensity invisible infrared beam which should be given to the photo diodes of receiver.
Note:

Operating voltage can be between 6V to 15V.
Relay voltage rating should be equal to the main power supply.
Heat sink can be attached to the transistor SK100 for compensating the heat dissipation.
Concave lens is used for producing the strong rays of high intensity.
The disadvantage in the circuit is switching time between the transmitter and receiver (if we produce the signal from transmitter, again we have to produce the signal after 5 to 6 seconds). Rapid switching like regular remote cannot be done.

Applications of Infrared Remote Control Switch:

This circuit can be used for switch ON or OFF the TV, radio, washing machine and any electronic appliances.
By using the relative relays, we can even switch ON or switch OFF the motor appliances also.