Automotive Turn Flasher with lamp output Detection

Here is a circuit of a flasher which I designed for automotive use. It has a built-in function of lamp-outage detection. In normal operation, it will flash at about 1.4Hz and when a lamp goes bad, the flash-rate is doubled. The flashers faster clicking sound and the dashboard indicators faster flashing attracts the drivers attention that one of the bulbs has gone out.

Automotive Turn Flasher with lamp  output Detection:

 
Notes
The circuit consists of two parts - the flashing unit and the lamp outage detection module. The flashing unit is built around 555 timer configured as an astable multivibrator. The resistors R12/R13 and capacitors C3/C4 sets the required frequency. Note that C3 is connected in parallel to C4 through BC547 an NPN transistor, acting as a switch. When there is positive voltage at the base of the transistor, it conducts and connects C3 to ground. C3 & C4 in parallel doubles the capacitance value i.e. 220nF + 220nF = 440nF. This capacitance value together with R12 and R13 result in frequency of about 1.4Hz.

In the lamp outage detection module, a shunt resistor (a thick wire) with a calculated minor resistance (30mΩ) is the key to detect the lamp outage. The voltage to lamps is fed thru this shunt. Hence, the shunt is connected in series to the network of the bulbs which are connected in parallel. The inverting input of the comparator U1 is also connected to the shunt. The non-inverting input is connected to a potential divider providing a reference voltage of 11.90V

NORMAL OPERATION:
Square wave between 11.89V - 12.0V at (-)ve input of U1
11.90V (reference voltage) at (+)ve input of U1

The comparator U1 compares these voltages and the output is a square wave between 0-12V. This output is rectified through diode D1 and filtered through capacitor C1. Now, we have a triangular wave form which is fed into another comparator U2.

1V (reference voltage) at the (-)ve input of U2 and
a triangular wave between 7V - 8V at (+)ve input of U2
OPERATION WITH A DEFECTIVE LAMP: OPERATION WITH A DEFECTIVE LAMP:
When a bulb is defective, there is an increase in the resistance of the bulb network hence the voltage drop across the shunt is changed. So, in this case we would have:

Square wave between 11.95V - 12.0V at (-)ve input of U1
11.90V (reference voltage) at (+)ve input of U1

The comparator U1 compares them and the output is almost zero volts. After the diode and the filter network, we finally have a few millivolts at the +input of U2 which is compared with the reference voltage, 1V. This results in low output of U2 which ultimately switches off the NPN and hence C3 is disconnected from the ground.

Now, the timing network of 555 has only C4 to work with, therefore the frequency of the oscillation is doubled. This causes the remaining bulbs to flash at doubled rate.

NOTE:
A single quad op-amp IC LM324 could also be used for building this circuit. Two of the op-amps to be used as comparators in place of U1 & U2. Another op-amp can be configured as astable oscillator in place of 555 to flash the bulbs. This astable oscillator will have two timing capacitors as used above with 555.

Source by: CirucitLead

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Simple 3-in-1 Flash Light Project

Want to avoid the problem of carrying three different flashlights to perform a test? Why don’t you try integrating Ultra Violet, Infra Red and visible light together in one flashlight? Read on to know more about this.

The multi-tasking flashlight is basically composed of a metallic case, a switch, cables and connections, four 9V batteries and three different LED heads that provide the desired light beam. For the construction of this flashlight, LedEngin’s LZ4-40 is recommended. This comes with a very wide wavelength that includes infra red and ultra violet light. Distinct visible light color temperature can also be found.

The first step is to build the body of the flashlight, using an aluminum tube. Next come the drilling and cutting for switches and covers. Once the body is finished, the work on the constant current driver should be completed, adding the proper terminals for the batteries and the base for the LED heads.

Once all the power source wiring is completed and insulated with heat shrink tubing, the LED heads are assembled and connected. These are basically composed of an aluminum cap. The LED base and the power source connections come from the batteries.

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Simple Sound Activated Lights

This sound activated lights circuit turns a lamp ON for a short duration when the dog barks (or a relatively strong sound) giving an impression that the occupants have been alerted. The condenser microphone fitted in a place to monitor sound and generates AC signals, which pass through DC blocking capacitor C1 to the base of transistor BC549 (T1). Transistor T1 along with transistor T2 amplifies the sound signals and provides current pulses from the collector of T2. When sound is produced in front of the condenser mic, triac1 (BT136) fires, activates lights and the bulb (B1) glows for about two minutes.

Sound Activated Lights Circuit Diagram:

 
Assemble the sound activated lights circuit on a general purpose PCB (circuit board) and enclose in a plastic cabinet. Power to the sound activated switch circuit can be derived from a 12V, 500mA step-down transformer with rectifier and smoothing capacitor. Solder the triac ensuring sufficient spacing between the pins to avoid short circuit. Fix the unit in the dog’s cage or close to the sound monitoring spot, with the lamp inside or outside as desired. Connect the microphone to the sount activated lights circuit using a short length of shielded wire. Enclose the microphone in a tube to increase its sensitivity.

Caution: Since the sound activated lights uses 230V AC, many of its points are at AC mains voltage. It could give you lethal shock if you are not careful. So if you don’t know much about working with line voltages, do not attempt to construct this circuit. We will not be responsible for any kind of resulting loss or damage.

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Police Lights associate crystal rectifier

This circuit uses a 555 timer that is setup to each runn in associate Astable operative mode. This generates a nonstop output via Pin three within the type of a sq. wave. once the timer's output changes to a high state this triggers the a cycle the 4017 4017 decade counter telling it to output consecutive sequent output high. The outputs of the 4017 ar connected to the LEDs turning them on and off.

Police Lights associate crystal rectifier Project:

 
Parts List:

1x - NE555 Bipolar Timer
1x - 4017 Decoded Decade
6x - 1N4148 Diode
1x - 1K Resistor (1/4W)
1x - 22K Resistor (1/4W)
2x - 4.7K Resistor (1/4W)
6x - 470 Resistor (1/4W)
1x - 2.2µF Electrolytic Capacitor (16V)
2x - BC547 NPN Transistor
2x - LED (Blue)
2x - LED (Red)
1x - 9V Voltage Battery

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USB Reading Lamp

Light your table top with this cool White LED Lamp. It is powered from the USB port and is ideal to take notes while browsing internet. The USB port can provide 5 volts and 100 mA current which is sufficient to light the LED lamp.

USB Reading Lamp Circuit diagram:

Power to the circuit is derived from the USB port using the standard A type plug. To give continuous regulated power, Zener regulation is employed. Resistor R1 restricts base current to T1 so that output will be current regulated. Since White LED requires minimum 3.6 volts, 4.7 volt Zener is used to provide constant 4.7 volts to LEDs. Resistor R2 restricts LED current to around 20 mA, so that they will not be damaged. Connect the power lines to USB plug observing correct polarity. Use a reflector for LEDs to get maximum illumination.

Pin out of SL 100

Author: D. MOHANKUMAR

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USB-Chargeable Emergency Inspection Light

Described is one USB-chargeable Emergency Inspection Light for in-lab use, wired around a hi-efficiency 5mm-white LED. The power-bank of this circuit is a 1F/5.5v (yes, 1 Farad!) super capacitor. Just connect your finished circuit to an active usb port, and push switch S1 when necessary. The result is a short-time white light from LED1, generated by the charge stored in C1. Fuse F1 in the circuit is added for usb port protection, and diode D1 works as a “one-way” switch. Resistor R1 limits the current (and hence the light output) through LED1.

USB-chargeable Emergency Inspection Light Circuit Diagram:

In the prototype, 1F/5.5V super capacitor took up from an old video cassette recorder was used. If you are using the commonly-available 1F/2.5v type super capacitor, you should connect two of them in series as shown here. Note that, this reduces the total capacitance, but doubles the voltage rating. Only one drawback of this idea is the undepicted price of the super capacitor; 1F/2.5v super capacitor in an Indian online store costs about 300 Indian Rupee (~ $5)!

(author’s prototype realized using cannibalized parts)

(1 farad super capacitor)

Note: Super capacitor is a special capacitor (electrochemical double layer capacitor) offers ultra-high capacitance and ultra-low equivalent series resistance. Super capacitors hold up power for long duration, and that’s why the LED in our circuit works for a finite duration even after it’s unplugged from the USB port.

Author: T.K. HAREENDRAN

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Lighting Garden with Solar Energy

Here is a very simple and effective circuit Project of Lighting Garden with Solar Energy Circuit Diagram. This is an economic circuit of a mini solar lighting system, solar panel 6V/2W is used to charge a rechargeable 4V/800mAh through a current limiting circuit load that uses a LM317T adjustable regulator 3 pin (IC1). Assuming a sunny day 6 hours, a panel will enviarr 2 watts for approximately 900mAh battery. The current can be reduced by increasing the value of R1, for example, 8.2 to 10 ohms ohms.

Lighting Garden with Solar Energy Circuit Diagram:

Specification of a typical solar panel:

6V/2W:Maximum power (Pm):
2WWorking Voltage (Vmp):
9VWorking Current (Imp):
220mAOpen Circuit Voltage (Voc):
10.5VPower Tolerance: -3% to 5%

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Outdoor Lighting Controller

When you step out of your brightly-lit house  into the darkness, it takes a while for your  vision to adjust. A solution to this problem  is this outdoor light with automatic switch-off. As a bonus, it will also make it a little bit  easier to find the keyhole when returning  late at night. Often no mains neutral connection is avail-able at the point where the switch-off timer  is to be installed, which makes many circuit  arrangements impractical.

However, the circuit here is designed to work in this situation. The design eschews bulky components such as transformers and the whole unit can  be built into a flush-mounted fitting. The circuit also features low quiescent current consumption.

Outdoor Lighting Controller Circuit Diagram:

The circuit is star ted by closing switch (or  pushbutton) S1. The lamp then immediately receives power via the bridge rectifier. The drop across diodes D5 to D10 is 4.2 V, which provides the power supply for the delay circuit itself, built around the CD4060 binary  counter.

When the switch is opened the lighting sup-ply current continues to flow through Tri1. The NPN optocoupler in the triac drive circuit detects when the triac is active, with antiparallel LED D1 keeping the drive sym-metrical. The NPN phototransistor inside the  coupler creates a reset pulse via T1, driving  pin 12 of the counter. This means that the  full time period will run even if the circuit is retriggered. The CD4060 counts at the AC grid frequency.  Pin 3 goes high after 213clocks, which corresponds to about 2.5 minutes. If this is not long  enough, a further CD4060 counter can be cascaded. T2 then turns on and shorts the internal LED of opto-triac IC2; this causes Tri1 to  be deprived of its trigger current and the light  goes out. The circuit remains without power until next triggered.

The circuit is only suitable for use with resistive loads. With the components shown (in particular in the bridge rectifier and D5 to  D10) the maximum total power of the connected bulb(s) is 200 watts. As is well known, the filament of the bulb is most likely to fail at the moment power is applied. There is little risk to Tri1 at this point as it is bridged by  the switch. The most likely consequence of overload is that one of diodes D1 to D6 will  fail. In the prototype no fuse was used, as it would not in any case have been easy to change. However, that is not necessarily recommended practice!

Circuits at AC line potential should only be constructed by suitably experienced persons and all relevant safety precautions and  applicable regulations must be observed during construction and installation.

Author : Harald Schad - Copyright : Elektor

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Simple Midnight Security Light

Most thefts happen after midnight hours when people enter the second phase of sleep called ‘paradoxical’ sleep. Here is an energy-saving circuit that causes the thieves to abort the theft attempt by lighting up the possible sites of intrusion (such as kitchen or backyard of your house) at around 1:00 am. It automatically resets in the morning. The circuit is fully automatic and uses a CMOS IC CD 4060 to get the desired time delay.

Light-dependent resistor LDR1 controls reset pin 12 of IC1 for its automatic action. During day time, the low resistance of LDR1 makes pin 12 of IC1 ‘high,’ so it doesn’t oscillate. After sunset, the high resistance of LDR1 makes pin 12 of IC1 ‘low’ and it starts oscillating, which is indicated by the fashing of LED2 connected to pin 7 of IC1. The values of oscillator components (resistors R1 and R2 and capacitor C4) are chosen such that output pin 3 of IC1 goes ‘high’ after seven hours, i.e., around 1 am.

Midnight Security Light Circuit Diagram:

This high output drives triac 1 (BT136) through D5 and R3. Bulb L1 connected between the phase line and M2 terminal of triac 1 turns on when the gate of triac 1 gets the trigger voltage from pin 3 of IC1. It remains ‘on’ until pin 12 of IC1 becomes high again in the morning. Capacitors C1 and C3 act as power reserves, so IC1 keeps oscillating even if there is power interruption for a few seconds. Capacitor C2 keeps trigger pin 12 of IC1 high during day time, so slight changes in light intensity don’t affect the circuit.

Using preset P1 you can adjust the sensitivity of LDR1. Power supply to the circuit is derived from a step-down transformer T1 (230V AC primary to 0-9V, 300mA secondary), rectifed by a full-wave rectifer comprising diodes D1 through D4 and fltered by capacitor C1. Assemble the circuit on a general-purpose PCB with adequate spacing between the components. Sleeve the exposed leads of the components. Using switch S1 you can turn on the lamp manually. Enclose the unit in a plastic case and mount at a location that allows adequate daylight.

Caution:
Since the circuit uses 230V AC, many of its points are at AC mains voltage. It could give you lethal shock if you are not careful. So if you don’t know much about working with line voltages, do not attempt to construct this circuit. We will not be responsible for any kind of resulting loss or damage. link

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Low-Cost and Low Voltage Flasher

This is Simple low-Cost Electronic Circuit of Low voltage flasher Circuit. Applying voltage to the circuit triggers SCR1. With SCRl on, the voltage on the anode of SCR2 rises until SCR2 triggers to commu-tate SCRl.

Low Voltage Flasher Circuit Diagram:

 
The voltage on the gate of SCRl will swing negative at this time, and only after a positive potential of 0 volt is once again attained, will SCRl retrigger The circuit could be used for higher voltage levels, but the peak negative voltage on the gate of SCRl must be limited to less than 6 volts.

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Simple Phase-Controlled Dimmer

Here is simple electronic circuit Project of phase-controlled dimmer circuit. A phase-controlled dimmer delays the triac turn-on to a selected point in each successive ac half cycle.

Phase-Controlled Dimmer Circuit Diagram:

 
Use this circuit only for incandescent lamps, heaters, soldering irons,or universal motors that have brushes.

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Automatically Lights On! Schematic

This circuit ensures that you will never again forget to switch on the lights of your car. As soon as the engine is running, the dipped beams and the sidelights are automatically switched on. The circuit also causes the dipped beams to be extinguished as soon as the main beams are switched on. As you can see from the schematic diagram, no special components are needed.

When the engine is running, the alternator will generate a voltage of more than 14 V. Diode D1 reduces this voltage by 5.6 V and passes it to the base of T1 via R1. Due to the resulting current, T1 conducts. The amplified current flows via R3, the base of T3 and D3 to ground. This causes T3 to also conduct and energize relay Re1.

Lights On  Circuit Diagram :

 
If the driver now switches on the main beams, a current flows through D2 and R2 into the base of T2, causing this transistor to conduct. As a result, the voltage on the base of T3 drops, causing T3 to cut off and the relay to drop out.

When the main beams are switched off, the previous situation is restored, and the relay again engages. The dipped beams and the sidelights are switched by the contacts of relay Re1. Diodes D5 and D6 ensure that the sidelights are illuminated if either the dimmed beams or the main beams are switched on. In practice, this means that the sidelights will be on whenever the engine is running, regardless of whether the main beams are switched on.

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Mini Running Text Display

This charming little circuit is a genuine four-digit running-text display, complete with a Christmas / New Year’s greeting. Naturally, any competent programmer can easily arrange to have a different text scroll across the display. The associated soft-ware, including the source code, can be downloaded from the Free Downloads section of our website or obtained from Readers Services on diskette (order number 020365-11).

Circuit Image :

As can be seen from the schematic, the hardware consists of little more than an AT90S1200 microcontroller, a 4-digit LED display and a 5-V voltage regulator. The only external circuitry needed by the microcontroller consists of a reset circuit and a 4-MHz crystal, and the remainder of the components are limited to a few decoupling capacitors.

Mini Running Text Display Circuit diagram : 

In the prototype model, an Osram SLO2016 display module was used. Although this four-digit module measures only 10×20 mm, it provides an especially clear and bright display. In order to give the 7805 voltage regulator sufficient ‘breathing room’, the supply voltage should be at least 8 V. A standard 9-V mains adapter should thus be perfectly adequate. The supply voltage does not have to be stabilised, and the adapter does not have to provide an especially large amount of current, since the running-text display draws scarcely more than 50 mA.Source: Link

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Simple Night Light

This is a low-cost and very simple electronic circuit projects of night light Circuit Diagram.  The two transistors are used as a direct coupled switch, Adam used 2SC711 but any general purpose transistor will do e.g. 2N3904, BC109C. The CDS photocell, type ORP12 is normally illuminated, therefore its resistance is low. The 50k control, the 1k resistor and the photocell form a potential divider which biases the first transistor. This transistor is on, its collector being held low, turns the last transistor and hence lamp and relay off.

Simple Night Light Circuit Diagram:

In darkness, the resistance of the photocell becomes high and the first transistor switches off. The base voltage for the second transistor goes high, switching this transistor on and illuminating the lamp. Although Adam used a secondary supply of 3V , you could use any voltage and any lamp here. Make sure the relay contacts can handle the load. If using a large relay, it is preferable to wire a 1N4001 in reverse polarity across the coil. This will prevent the back EMF of the relay from damaging the transistors.

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Low-Cost and Low Frequency Oscillator-Flasher

It is a low-cost circuit diagram project for Low Frequency Oscillator-Flasher Circuit. Electrolytic capacitors are unnecessary to generate a 1 cps frequency. As an scs triggers on, the 0.2 µ¥ commutating capacitor turns off the other one and charges its gate capacitor to a negative potential.

Low-Cost and Low Frequency Oscillator-Flasher Circuit Diagram:

The gate capacitor charges towards 24 volts through 20 retriggering its scs. Battery power is delivered to the load with 88% efficiency.  The 20 resistors can be varied to change prf or duty factor.

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Light Dependent Sensor For Multiple Inputs

This is a very easy make electronic Circuit project of Light-Dependent Sensor For Multiple Inputs Circuit. Light-dependent sensor uses LDRs to detect the presence or absence of light.

Light-Dependent Sensor For Multiple Inputs Circuit Diagram:

As long as the light source striking the LDRs remains constant, the alarm does not sound. But when the light is interrupted, the alarm is triggered.

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Simple Flash Blinky Lights

This a very simple Electronic Circuit Diagram Project of flash light circuit.  Flash light circuit can be designed using common electronic components. As you can see in this flash light circuit schematic, this electronic project can be designed using few electronic components. When the S1 switch is closed, power is applied to U1 and U2.

Simple Flash Blinky Lights Circuit Diagram:

Two inverters of U2,a 4049 hex inverter buffer , are connected in a low frequency oscillator circuit that feeds clock pulses into U1, a 4017 decade counter . Outputs 0,2,4,6 and 8 of U1 are coupled to the gate of Q1 through a 1N914 diode. As the 4017 counts down, it turns the light on and off four times and then leaves it on until the S1 switch is released .

The on off rate can be set by R2 potentiometer. For best results, the on off rate should be set so that it is rapid.

This flash light electronic project must be powered from a 12 volt DC power supply.

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Photo Electric Street Light

This is basically a Schmitt Trigger circuit which receives input from a cadmium sulfide photo cell and controls a relay that can be used to switch off and on a street lamp at dawn and dusk. I have built the circuit with a 120 ohm/12 volt relay and monitored performance using a lamp dimmer, but did not connect the relay to an outside light.

Photo Electric Street Light Circuit Diagram:

The photo cell should be shielded from the lamp to prevent feedback and is usually mounted above the light on top of a reflector and pointed upward at the sky so the lamp light does not strike the photo cell and switch off the lamp.

The photo cell is wired in series with a potentiometer so the voltage at the junction (and base of transistor) can be adjusted to about half the supply, at the desired ambient light level. The two PNP transistors are connected with a common emitter resistor for positive feedback so as one transistor turns on, the other will turn off, and visa versa. Under dark conditions, the photo cell resistance will be higher than the potentiometer producing a voltage at Q1 that is higher than the base voltage at Q2 which causes Q2 to conduct and activate the relay.

The switching points are about 8 volts and 4 volts using the resistor values shown but could be brought closer together by using a lower value for the 7.5K resistor. 3.3K would move the levels to about 3.5 and 5.5 for a range of 2 volts instead of 4 so the relay turns on and off closer to the same ambient light level. The potentiometer would need to be readjusted so that the voltage is around 4.5 at the desired ambient condition.

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Half wave AC Phase Controlled

This is very simple circuit diagram of  Half wave AC Phase Controlled Circuit.  The 5AH will trigger when the voltage across the two 0 juF capacitors reaches the breakdown voltage of the lamp.

Half wave AC Phase Controlled Circuit Diagram:

Control can be obtained full off to 95% of the half wave RMS output voltage Full power can be obtained with the addition of the switch across the SCR.

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Phase-Controlled Dimmer

Here is a simple electronic circuit project of  Phase-Controlled Dimmer Circuit. A phase-controlled dimmer delays the triac turn-on to a selected point in each successive ac half cycle.

Phase-Controlled Dimmer Diagram:

Use this circuit only for incandescent lamps, heaters, soldering irons,or universal motors that have brushes.

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