12V Battery level indicator

Hi friends today I have brought you some thing special.Actually this would be a very interesting topic for our vehicle lovers.Today Free Circuit Diagrams 4U is going to give you a 12V battery level indicator circuit diagram.According to the battery voltage LEDS will light up.

Note: #  To get maximum result build this circuit on a pcb.
          # Don't forget this is a 12V power circuit diagram

Simple touch lamp curcuit

Hi everyone today we have decided to give you a touch lamp circuit diagram.This circuit is operated with 12 V power.And here we have used 2N2905 ,2N3906 and 2N3055 transistors.Personally I think this is a best circuit to modify your car or van.Not only that you can attach this circuit to your motorcycle too.If you want to connect this circuit you can do that via a relay.Before this post Free Circuit Diagrams 4U has given you simple circuit diagrams  Clich here to see Have a nice day.

Simple touch sensitive circuit diagram

Most of the people requested touch sensitive circuit diagrams from FREE CIRCUIT DIAGRAMS 4U .So today we hope to give you a touch sensitive circuit diagram.Here we have used NE555 IC.This circuit can be operated with 6V power.Removing the led you can attach a relay for the circuit.

Note:     # Build this circuit on a pcb   
             # Don't supply over 6V

Simple Dark Activated Switch

You all know FREE CIRCUIT DIAGRAMS 4U always try to give simple and useful circuit diagrams.Today we are going to give you a Simple dark activated circuit diagram.When the dark comes this circuit will activated.This circuit is operated with 12v power.Most of time these types of circuits are used to design robot hands etc.And also you can make a counter of people.For that you can use a lazer pointer and aim it to the LDR.When a person is passing.Lazer beam will cut due to that the circuit will activate.you can use this circuit for various things so try this...

Note:
        # Build this circuit on a PCB 
        # Don't supply over 12V

Touch Sensitive Circuit Diagram

This is  a touch sensitive circuit diagram.At present we can see vehicle manufactures have made touch sensitive electronic equipments with their cars.So I suppose this will be a useful circuit for you all guys.This circuit can be operated with 12 V so that you can fix this circuit with your car directly.Use a copper plate as the touch plate.

Note:
         # Build this circuit on a pcb

simple coir dust meter

Last few days I did some experiment regarding coir dust meters. At that time I could made this simple circuit diagram.Here I have used common Transistor Bc 547. Really this is a water sensitive circuit.We can use this circuit to measure whether coir dust is wet or dry.

Smoke sensitive circuit diagram

Here I am going to introduce you a very important circuit.It is nothing but a smoke sensitive circuit .In the market we can see there are lots of expensive smoke sensitive kits.But I'm going to give you a very simple method to make a smoke detector.Here i have used a dark sensitive circuit.When the smoke goes via LEDs and LDR it will generates a sound.If you want to operate another circuit firstly remove the speaker and add a really for there.then you can operate your circuit through that really.

Water sensitive circuit diagram

This is a water sensitive circuit diagram.I suppose this circuit will give you lots of benefits .I have modified this circuit up to some extent and have added to our water pump moter (230 v) I think you also can use this circuit for various purposes.Here I have used common IC Bc109. When you fix the sensor Don't forget to fix it over the water level.This circuit operates with 4.5V to 6v.If you want to operate your water pump 230V 0r 110V you can use a rellay for that.Then this circuit will switch on or off that rellay( use 6V rellay)

Dark Activated Micro circuit diagram

This is dark activated circuit diagram.But the importance of this circuit is the size of this circuit.Here I have used famous transistor 2N3904.Here I have used photo transistor.

Sound activated ( switch off) Switch

This circuit is a sound activated switch.After making a sound you can switch off this circuit.If you want to switch on this circuit after the sound use a relay for that.(That means When the relay switch on the circuit will switch off And when the relay switch off circuit will switch on)

Dark activated Switch (Ac)

This is dark activated Circuit here you can operate this circuit from dc but you can control AC Bulb.I took this circuit from my old book.When I was in my child hood I made lots of circuit like this.

Dark & Light detector in the same circuit

Already I have given you dark activated and Light activated alarm circuits.But this circuit is totally different circuit because this circuit contains dark activated and light activated both parts.This circuit should be given 9V power.You can select Dark activated or light activated mood according to s1 switch.

Touch Alarm circuit

This is touch alarm circuit.Here I have used very common Ic NE555 And common parts.Then easily you can make your circuit.You can attach this circuit for your door lock or for any other metal part.If some one touched that metal part the alarm will start to ring.You can use this circuit as a security circuit.Even you can attach this circuit for your fence.





Parts

# Transistor 2N3904
# Diode 1N4004
# IC LM555
# Relay
# Resistor 56 K
# Resistor 100 K
# Resistor 10 M
# Resistor 220 K
# Capacitor 47 uF at 16 V
# Capacitor 33 uF at 16 V
# Potentiometer 100 K

Note

# This circuit operates with 6V battery
#Connect touch pad to the metal plate of your main door or fence

Water Level Ditector Circuit

This is very useful circuit for us.Because by using this circuit you can control your water pump automatically.When the water goes down the trigger sensor level.The mot er will start automatically.After passing the threshold sensor level the mot er Will stop automatically.









Note

# When you fix sensors fix them tiddly.If not They will short together.
#This circuit works with 12V power supply.

Rain detector

People have to face to various problems because of not having proper way to know the rain before it comes.So through this circuit you can detect rain comes or not.When a small drop water falls on the sensor Circuit gives a sound.you can use this one for various purposes.As an example you can use this one to detect your over flowing water tank.And I myself have used this one for various things....





Parts

D1 1N4001 Silicon Diode
BZ1 12V Buzzer
R1 1K 1/4 W Resistor
R2 680 Ohm 1/4 W Resistor
S1 SPST Switch
SCR1 C106B1 SCR 106CY
SENSOR See Notes
MISC Board, Wire, Case, PC Board (For Sensor)

Ultrasonic switch

circuit of a new type of remote control switch is described here. This circuit functions with inaudible (ultrasonic) sound. Sound of frequency up to 20 kHz is audible to human beings. The sound of frequency above 20 kHz is called ultrasonic sound. The circuit described generates (transmits) ultrasonic sound of frequency between 40 and 50 kHz. As with any other remote control system this cirucit too comprises a mini transmitter and a receiver circuit.









Transmitter generates ultrasonic sound and the receiver senses ultrasonic sound from the transmitter and switches on a relay. The ultrasonic transmitter uses a 555 based astable multivibrator. It oscillates at a frequency of 40-50 kHz. An ultrasonic transmitter transducer is used here to transmit ultrasonic sound very effectively. The transmitter is powered from a 9-volt PP3 single cell. The ultrasonic receiver circuit uses an ultrasonic receiver transducer to sense ultrasonic signals. It also uses a two-stage amplifier, a rectifier stage, and an operational amplifier in inverting mode. Output of op-amp is connected to a relay through a complimentary relay driver stage. A 9-volt battery eliminator can be used for receiver circuit, if required. When switch S1 of transmitter is pressed, it generates ultrasonic sound. The sound is received by ultrasonic receiver transducer. It converts it to electrical variations of the same frequency. These signals are amplified by transistors T3 and T4. The amplified signals are then rectified and filtered. The filtered DC voltage is given to inverting pin of op-amp IC2. The non- inverting pin of IC2 is connected to a variable DC voltage via preset VR2 which determines the threshold value of ultrasonic signal received by receiver for operation of relay RL1. The inverted output of IC2 is used to bias transistor T5. When transistor T5 conducts, it supplies base bias to transistor T6. When transistor T6 conducts, it actuates the relay. The relay can be used to control any electrical or electronic equipment. Important hints:
1. Frequency of ultrasonic sound generated can be varied from 40 to 50 kHz range by adjusting VR1. Adjust it for maximum performance.
2. Ultrasonic sounds are highly directional. So when you are operating the switch the ultrasonic transmitter transducer of transmitter should be placed towards ultrasonic receiver transducer of receiver circuit for proper functioning.
3. Use a 9-volt PP3 battery for transmitter. The receiver can be powered from a battery eliminator and is always kept in switched on position.
4. For latch facility use a DPDT relay if you want to switch on and switch off the load. A flip-flop can be inserted between IC2 and relay. If you want only an ‘ON-time delay’ use a 555 only at output of IC2. The relay will be energised for the required period determined by the timing components of 555 monostable multivibrator.
5. Ultrasonic waves are emitted by many natural sources. Therefore, sometimes, the circuit might get falsely triggered, espically when a flip-flop is used with the circuit, and there is no remedy for that