Top Circuits Page 194
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Agreeable, very close sound imitation, Suitable for sound effects, door-bells etc. This circuit generates a two-tone effect very much alike the cuckoo son....
-
-
LED sequencer: follows the rhythm of music or speech, 9V Battery-operated portable unit The basic circuit illuminates up to ten LEDs in sequence, followin....
-
Compact circuit, Can be wired in parallel to existing switches This device allows one or more lamps to illuminate at sunset and turn off at dawn.Q1 and Q2....
-
The dark detector circuit shown here can be used to produce an audible alarm when the light inside a room goes OFF. The circuit is build around timer IC N....
-
If a circuit is to switch a mains voltage, a relay is a simple solution in cases where switching times are long and high currents are involved. However, a....
-
Designs for audio amplifiers with DC coupling to the load are not often encountered these days, even though they offer definite advantages. One advantage....
-
-
This circuit takes advantage of the voltage drop across bridge rectifier diodes to produce a 5-position variable voltage supply to a DC fan or other small DC motor. It is not as efficient as a switch-mode circuit but it has the virtues of simplicity and no....
-
A popular project among microcontroller aficionados is to build a radio-controlled clock. Tiny receiver boards are available, with a pre-adjusted ferrite....
-
This digital DIY tachometer for bikes uses two reed switches to get the speed information of the bicycle. The reed switches are installed near the rim of....
-
Remote sensor sends data via mains supply, Temperature range: 00.0 to 99.9 °C This circuit is intended for precision centigrade temperature measurement, w....
-
This circuit measures the distance covered during a walk. Hardware is located in a small box slipped in pants` pocket and the display is conceived in the following manner: the leftmost display D2 (the most significant digit) shows 0 to 9 Km. and its dot is....
-
-
This circuit shows that dimmers intended for use at mains voltage do not always have to contain a triac. Here, a MOSFET (BUZ41A, 500 V/4.5A) in a diode br....
-
PWM waveforms are commonly used to control the speed of DC motors. The mark/space ratio of the digital wave-form can be defined either by using an adjusta....
-
This simple robot, which responds to light and avoids obstacles, can be built without using a microcontroller, programmer or PC. The only special` component in the circuit is a window discriminator (a fancy version of a window comparator). Resistors R1 and....
-
Chris has a great article about a do-it-yourself radar system build with PIC18F452. It s a great hobby project although the schematic....
-
This tremolo effect circuit uses the XR2206 and the TCA730 IC which is designed as an electronic balance and volume regulator with frequency correction. The circuit is use full for stereo channels and it also has the ability to simulate the Lesley effect aka....
-
Sometimes you have to do it the hard way, even if doing it the easy way is an option. That is the case here. The intention is to add a second doorbell in....
-
If you re expecting an important visitor but you just have to step out for a moment, an electronic doorbell memory can come in handy so you can see whethe....
-
The State Jal Boards supply water for limited duration in a day. Time of water supply is decided by the management and the public does not know the same ..
-
This project came about due to my interest in a new form of radio transmission called DRM, which stands for Digital Radio Mondial....
-
A DTMF-based IR transmitter and receiver pair can be used to realize a proximity detector. The circuit presented here enables you to detect any object capable of reflecting the IR beam and moving in front of the IR LED photo-detector pair up to a distance of....
-
This circuit takes two separate line-level stereo (L & R) signals and combines them into one stereo (L & R) output, thus avoiding the need to switch betwe....
-
The circuit in Fig 1 supplies both 3.3 and 5V to transitional circuits that employ both the new 3.3V and older 5V devices. Additionally, because the regul....
-
This relay driver boosts the input impedance with a regular BC547 NPN transistor (or equivalent). Very common driver. It can drive a variety of relays, including a reed-relay. Transistor Q1and Q2 are a simple common-emitter amplifier that increases the....
-
This LED lamp was originally designed for use on a budget solar-charged 12V electrical system. It is bright enough for comfortable reading at night and fe....
-
Depending on its design an electric guitar may have anything from one to six pickup elements. Classic (acoustic) guitars could also benefit from one or mo....
-
When the SDA (Serial DAta) lines on both the left and right lines are 1, the circuit is quiescent and optoisolators IC1 and IC2 are not actuated. When the....
-
While many power supplies can be set to limit their output current to a defined level, to protect the circuit they are powering, no such protection is ava....
-
Although it does not have the same charm as real mercury barometers with long glass tubes on pieces of carved and polished wood, the Torricelli barometer....
-
Mechanical contacts have the disadvantage that they wear out. That is why it is practical to use an electronic ‘touch switch in some situations. With suc....
-
This circuit is permanently plugged into a mains socket and NI-CD batteries are trickle-charged. When a power outage occurs, the lamp automatically illuminates. Instead of illuminating a lamp, an alarm sounder can be chosen. When power supply is restored,....
-
This sensitive circuit is basically a comparator, detecting very slight temperature changes in respect to the ambient temperature. It was primarily intended to detect draughts around doors and windows that cause energy leaks but can be used in many other....
-
Using this design, you can construct an electromagnetically impulsed pendulum clock with a 1-second beat. On the prototype, the pendulum rod is 115cm long with a bob adjusted to make it beat every second. It is suspended on a short piece of mainspring from a....
-
This circuit operates two LED strips in pulsing mode, i. e. one LED strip goes from off state, lights up gradually, then dims gradually, etc. while the other LED strip does the contrary. Each strip can be made up from 2 to 5 LEDs at 9V supply. The two....
-
Using the FAN7710 Ballast Control IC for Compact Fluorescent Lamps developed using Fairchild s unique highvoltage process and system-in-package (SiP) conc....
-
A fast electronic fuse designed to operate on 230V AC with an adjustable trip current. When the current through the load exceeds a level determined by the....
-
The current source in the diagram, which react very fast to changes in the input signal, may be used, for instance, in certain measurements. Differential....
-
Small and simple unit, Can be used for Home-Security purpose In this fire alarm circuit, a Thermistor works as the heat sensor. When temperature increases....
-
A Battery-status Indicator circuit can be useful, mainly to monitor portable Test-gear instruments and similar devices. LED D1 flashes to attire the user`s attention, signaling that the circuit is running, so it will not be left on by mistake. The circuit....
-
Regardless of whether you want to effectively imitate a house fire, a campfire, or light from welding, the circuit described here fills the bill without u....
-
Although not a new device, the LM317 is still a high-performance regulator. Its output voltage is essentially immune to fluctuations in load, supply volta....
-
You ll find that this is a very easy project to build. It will transmit good quality sound in the FM band ( 88 108 mhz ). One inportant item is that the....
-
Here is a very simple, inexpensive and interesting project which provides lot of fun to a home experimenter or hobbyist. This simple transmitter can trans....
-
A rear fog lamp has been mandatory for trailers and caravans in order to improve visibility under foggy conditions. When this fog lamp is switched on, the fog lamp of the pulling vehicle must be switched off to avoid irritating reflections. For this purpose,....
-
This circuit enables you to display four signals simultaneously using only one channel of your oscilloscope. Essentially, it switches each of the inputs t....
-
This 2 meter 144 MHz fox hunt transmitter is used in amateur competitions where a hidden transmitter is to be “hunted†using mostly home brewed receivers....
-
Beeps if you leave open the door over 20 seconds This circuit, enclosed into a small box, is placed in the fridge near the lamp (if any) or the opening. W....
-
The main purpose of this design was to obviate a small defect of the very popular Fridge Door Alarm circuit, available on this website since 1999 and built by a lot of hobbyists. Unfortunately, that circuit stops operating when the battery voltage falls....
-
This design allows to operate two intercom stations leaving the operator free of using his/her hands in some other occupation, thus avoiding the usual push-to-talk operation mode. No complex changeover switching is required: the two units are connected....
-
The recent tsunami in Japan and the on-going calamity with the Fukushima nuclear power plant has apparently greatly increased sales of radiation meters, n....
-
This circuit using a dual-timer NE556 can produce 1Hz pulses spaced 5 seconds apart, either manually or automatically. IC NE556 comprises two independent....
-
Stand-alone, 9V battery powered unit, Three-level input selector, three-band tone control This preamplifier was designed as a stand-alone portable unit, u....
-
Most dimmers use pulse width modulation (PWM) to control the amount of power that is delivered to the lamp. Those that come bundled with a switch faceplat....
-
This circuit is designed to provide delayed relay switching action at power on. The delay is a function of the time constant produced by the combination o....
-
In these times with viruses and other threats from the Internet it would be nice to have reassurance that the PC cannot be infected. That is why this circ....
-
Quartz crystals have the property that their amplitude/phase characteristic repeats itself at frequencies that are an uneven multiple of the fundamental f....
-
Strictly speaking, this simple circuit shouldn t work! How could anyone expect an ordinary light dependent resistor photo cell to ‘see through a fingerti....
-
Controlled by indoor and outdoor temperature, Simple, high reliability design This circuit is intended to control a heating system or central heating plan....
-
If you have a motley collection of 12V batteries in varying states of health, this simple circuit will allow you to easily check their capacity. It s basi....
-
This circuit was designed to allow a laptop computer to be powered from a solar power setup. The computer requires 12V at 3.3A. The circuit is a linear re....
-
This circuit was designed as a warning flasher to alert road users to dangerous situations in the dark. Alternatively, it can act as a bicycle light (subj....
-
This inexpensive circuit can be connected to an air-conditioner/fridge or to any other sophisticated electrical appliance for its protection. Generally, c....
-
An interesting circuit of a bicycle horn based on a popular, low cost telecom ringer chip is described here. This circuit can be powered using the bicycle dynamo supply and does not require batteries, which need to be replaced frequently. The section....
-
To operate car audio (or video) system from household 230V AC mains supply, you need a DC adaptor. DC adapters available in the market are generally costl....
-
There are many circuits for low voltage regulators. For higher voltages, such as supplies for valve circuits, the situation is different. That s why we de....
-
This circuit is designed to switch on/off any home or industrial appliance by using the TV/DVD remote controller. The circuit can be operated up to a dist....
-
This homemade metal detector circuit will help you find objects composed of materials with relatively high magnetic permeability. It is not suitable for b....
-
Have you ever connected two PCs together via modems using a twisted pair cable and nothing happened? That s because the modems are expecting a phone line....
-
Potentially, headphone listening can be technically superior since room reflections are eliminated and the intimate contact between transducer and ear mea....
-
Here is the circuit diagram of IC Controlled Emergancy Light With Charger or simply 12V to 220V AC inverter circuit. The circuit shown here is that of the IC controlled emergency light. Its main features are: automatic switching-on of the light on mains....
-
This circuit was devised to switch power to a Peltier cooler in a vehicle. Power to the load from the vehicle s battery is switched by a SPDT relay while....
-
This remotely controlled watering system is both inexpensive and easy to expand. It is designed to operate in conjunction with a conventional watering tim....
-
Useful for liquids level detection and proximity devices, Up to 50 cm. range, optional relay operation This circuit is useful in liquids level or proximit....
-
This is a short-range light barrier for use as an intruder alarm in doorposts, etc. The 555 in the transmitter (Figure 1) oscillates at about 4.5 kHz, sup....
-
Firecrackers are normally ignited by using a matchstick or a candle. You have to run away quickly after igniting the fuse of the firecracker. This method....
-
This circuit can be built from readily available low-cost components, some of which may even be hiding in your junkbox! The indicated value of 22 ? for re....
-
This 555 timer circuit Remote control Jammer device it s useful when we need to block someone to use the remote control (children that change frequently t....
-
The infrared detector module (GP1U52X) (Radio Shack 276-137) provides a 5 volt TTL pulse train corresponding to the digital code to the button of the remote control. In the lower circuit, the module output normally low a signal and a positive going pulse....
-
This project sprang from the need to be able to remotely control audio-visual equipment placed inside cupboards. RF-based commercial units such as those u....
-
This add-on circuit enables remote switching on/off of battery-operated toy cars with the help of a TV/video remote control handset operating at 3040 kHz....
-
Here is a simple but inexpensive inverter for using a small soldering iron (25W, 35W, etc) In the absence of mains supply. It uses eight transistors and a....
-
Portable loads such as video cameras, halogen flood lights, electrical irons, hand drillers, grinders, and cutters are powered by connecting long 2- or 3-....
-
This is an Infrared beam breaking alarm ideal to use in entry or passages.It is based on the working of the popular IR sensor Module TSOP 1738 which sense....
-
Men in particular enjoy the convenience of television remote controls often to the annoyance of their female partners. Men apparently want to know what....
-
Using this circuit, audio musical notes can be generated and heard up to a distance of 10 metres. The circuit can be divided into two parts: IR music tran....
-
Turn ON or OFF electrical devices using remote control is not a new idea and you can find so many different devices doing that very well. For realization....
-
With many audio systems consisting of separate units, you ll often ?nd that due to economic reasons only the amplifier has a remote control receiver modul....
-
This small circuit is ideal for checking the basic operation of an infrared remote control unit. The circuit is based on the brilliantly simple idea of connecting a piezo buzzer directly to an IR receiver IC. This method is almost as simple as connecting a....
-
Many modern motherboards are equipped with an infrared data interface compliant with the IrDA standard, but this interface not very often used. However, i....
-
Two multivibrators with different frequencies can be built using the NAND gates of a 4011 IC. If the output of IC1. B is positive with respect to IC1. C, LED D1 is on. As the levels of IC1. A and IC1. D are exactly opposite, D2 is always on when D1 is off,....
-
This simple circuit proves to achieve surprisingly good results when used with the IRS/PDIF transmitter described elsewhere in this site. The IR receiver....
-
The best-known ways to transmit a digital audio signal (S/PDIF) are to use a standard 75? coaxial cable or Toslink optical modules with matching optical c....
-
3V Battery powered, Beeps after a fixed minutes delay This circuit was developed since a number of visitors of this website requested a timer capable of e....
-
Exhaust fan is an important component in kitchens. Here is a simple circuit to control kitchen fans by monitoring the ambient temperature. It is built aro....
-
A lambda probe (or oxygen sensor) can be found on the exhaust system of most cars running on unleaded fuel. Having reached its normal operating temperatur....
-
Protect your valuable laptop against theft using this miniature alarm generator. Fixed in-side the laptop case, it will sound a loud alarm when someone tr....
-
This circuit is a laser alarm system like the one we see in various movies. It uses a laser pointer beam to secure your valuables and property. Essentially, when the beam gets interrupted by a person, animal or object, the resistance of a photodiode will....
-
This circuit is built around a 555 timer using very few components. Since the circuit is very simple, even a novice can easily build it and use it as a co....
-
This automatic door opener can be made using readily available components. The electromagnetic relay at the output of this gadget can be used to control t....
-
In many projects use is made of alphanumeric LCDs that are driven internally by Hitachi s industry-standard HD44780 controller. These displays can be driv....
Agreeable, very close sound imitation, Suitable for sound effects, door-bells etc. This circuit generates a two-tone effect very much alike the cuckoo son....
LED sequencer: follows the rhythm of music or speech, 9V Battery-operated portable unit The basic circuit illuminates up to ten LEDs in sequence, followin....
Compact circuit, Can be wired in parallel to existing switches This device allows one or more lamps to illuminate at sunset and turn off at dawn.Q1 and Q2....
The dark detector circuit shown here can be used to produce an audible alarm when the light inside a room goes OFF. The circuit is build around timer IC N....
If a circuit is to switch a mains voltage, a relay is a simple solution in cases where switching times are long and high currents are involved. However, a....
Designs for audio amplifiers with DC coupling to the load are not often encountered these days, even though they offer definite advantages. One advantage....
This circuit takes advantage of the voltage drop across bridge rectifier diodes to produce a 5-position variable voltage supply to a DC fan or other small DC motor. It is not as efficient as a switch-mode circuit but it has the virtues of simplicity and no....
A popular project among microcontroller aficionados is to build a radio-controlled clock. Tiny receiver boards are available, with a pre-adjusted ferrite....
This digital DIY tachometer for bikes uses two reed switches to get the speed information of the bicycle. The reed switches are installed near the rim of....
Remote sensor sends data via mains supply, Temperature range: 00.0 to 99.9 °C This circuit is intended for precision centigrade temperature measurement, w....
This circuit measures the distance covered during a walk. Hardware is located in a small box slipped in pants` pocket and the display is conceived in the following manner: the leftmost display D2 (the most significant digit) shows 0 to 9 Km. and its dot is....
This circuit shows that dimmers intended for use at mains voltage do not always have to contain a triac. Here, a MOSFET (BUZ41A, 500 V/4.5A) in a diode br....
PWM waveforms are commonly used to control the speed of DC motors. The mark/space ratio of the digital wave-form can be defined either by using an adjusta....
This simple robot, which responds to light and avoids obstacles, can be built without using a microcontroller, programmer or PC. The only special` component in the circuit is a window discriminator (a fancy version of a window comparator). Resistors R1 and....
Chris has a great article about a do-it-yourself radar system build with PIC18F452. It s a great hobby project although the schematic....
This tremolo effect circuit uses the XR2206 and the TCA730 IC which is designed as an electronic balance and volume regulator with frequency correction. The circuit is use full for stereo channels and it also has the ability to simulate the Lesley effect aka....
Sometimes you have to do it the hard way, even if doing it the easy way is an option. That is the case here. The intention is to add a second doorbell in....
If you re expecting an important visitor but you just have to step out for a moment, an electronic doorbell memory can come in handy so you can see whethe....
The State Jal Boards supply water for limited duration in a day. Time of water supply is decided by the management and the public does not know the same ..
This project came about due to my interest in a new form of radio transmission called DRM, which stands for Digital Radio Mondial....
A DTMF-based IR transmitter and receiver pair can be used to realize a proximity detector. The circuit presented here enables you to detect any object capable of reflecting the IR beam and moving in front of the IR LED photo-detector pair up to a distance of....
This circuit takes two separate line-level stereo (L & R) signals and combines them into one stereo (L & R) output, thus avoiding the need to switch betwe....
The circuit in Fig 1 supplies both 3.3 and 5V to transitional circuits that employ both the new 3.3V and older 5V devices. Additionally, because the regul....
This relay driver boosts the input impedance with a regular BC547 NPN transistor (or equivalent). Very common driver. It can drive a variety of relays, including a reed-relay. Transistor Q1and Q2 are a simple common-emitter amplifier that increases the....
This LED lamp was originally designed for use on a budget solar-charged 12V electrical system. It is bright enough for comfortable reading at night and fe....
Depending on its design an electric guitar may have anything from one to six pickup elements. Classic (acoustic) guitars could also benefit from one or mo....
When the SDA (Serial DAta) lines on both the left and right lines are 1, the circuit is quiescent and optoisolators IC1 and IC2 are not actuated. When the....
While many power supplies can be set to limit their output current to a defined level, to protect the circuit they are powering, no such protection is ava....
Although it does not have the same charm as real mercury barometers with long glass tubes on pieces of carved and polished wood, the Torricelli barometer....
Mechanical contacts have the disadvantage that they wear out. That is why it is practical to use an electronic ‘touch switch in some situations. With suc....
This circuit is permanently plugged into a mains socket and NI-CD batteries are trickle-charged. When a power outage occurs, the lamp automatically illuminates. Instead of illuminating a lamp, an alarm sounder can be chosen. When power supply is restored,....
This sensitive circuit is basically a comparator, detecting very slight temperature changes in respect to the ambient temperature. It was primarily intended to detect draughts around doors and windows that cause energy leaks but can be used in many other....
Using this design, you can construct an electromagnetically impulsed pendulum clock with a 1-second beat. On the prototype, the pendulum rod is 115cm long with a bob adjusted to make it beat every second. It is suspended on a short piece of mainspring from a....
This circuit operates two LED strips in pulsing mode, i. e. one LED strip goes from off state, lights up gradually, then dims gradually, etc. while the other LED strip does the contrary. Each strip can be made up from 2 to 5 LEDs at 9V supply. The two....
Using the FAN7710 Ballast Control IC for Compact Fluorescent Lamps developed using Fairchild s unique highvoltage process and system-in-package (SiP) conc....
A fast electronic fuse designed to operate on 230V AC with an adjustable trip current. When the current through the load exceeds a level determined by the....
The current source in the diagram, which react very fast to changes in the input signal, may be used, for instance, in certain measurements. Differential....
Small and simple unit, Can be used for Home-Security purpose In this fire alarm circuit, a Thermistor works as the heat sensor. When temperature increases....
A Battery-status Indicator circuit can be useful, mainly to monitor portable Test-gear instruments and similar devices. LED D1 flashes to attire the user`s attention, signaling that the circuit is running, so it will not be left on by mistake. The circuit....
Regardless of whether you want to effectively imitate a house fire, a campfire, or light from welding, the circuit described here fills the bill without u....
Although not a new device, the LM317 is still a high-performance regulator. Its output voltage is essentially immune to fluctuations in load, supply volta....
You ll find that this is a very easy project to build. It will transmit good quality sound in the FM band ( 88 108 mhz ). One inportant item is that the....
Here is a very simple, inexpensive and interesting project which provides lot of fun to a home experimenter or hobbyist. This simple transmitter can trans....
A rear fog lamp has been mandatory for trailers and caravans in order to improve visibility under foggy conditions. When this fog lamp is switched on, the fog lamp of the pulling vehicle must be switched off to avoid irritating reflections. For this purpose,....
This circuit enables you to display four signals simultaneously using only one channel of your oscilloscope. Essentially, it switches each of the inputs t....
This 2 meter 144 MHz fox hunt transmitter is used in amateur competitions where a hidden transmitter is to be “hunted†using mostly home brewed receivers....
Beeps if you leave open the door over 20 seconds This circuit, enclosed into a small box, is placed in the fridge near the lamp (if any) or the opening. W....
The main purpose of this design was to obviate a small defect of the very popular Fridge Door Alarm circuit, available on this website since 1999 and built by a lot of hobbyists. Unfortunately, that circuit stops operating when the battery voltage falls....
This design allows to operate two intercom stations leaving the operator free of using his/her hands in some other occupation, thus avoiding the usual push-to-talk operation mode. No complex changeover switching is required: the two units are connected....
The recent tsunami in Japan and the on-going calamity with the Fukushima nuclear power plant has apparently greatly increased sales of radiation meters, n....
This circuit using a dual-timer NE556 can produce 1Hz pulses spaced 5 seconds apart, either manually or automatically. IC NE556 comprises two independent....
Stand-alone, 9V battery powered unit, Three-level input selector, three-band tone control This preamplifier was designed as a stand-alone portable unit, u....
Most dimmers use pulse width modulation (PWM) to control the amount of power that is delivered to the lamp. Those that come bundled with a switch faceplat....
This circuit is designed to provide delayed relay switching action at power on. The delay is a function of the time constant produced by the combination o....
In these times with viruses and other threats from the Internet it would be nice to have reassurance that the PC cannot be infected. That is why this circ....
Quartz crystals have the property that their amplitude/phase characteristic repeats itself at frequencies that are an uneven multiple of the fundamental f....
Strictly speaking, this simple circuit shouldn t work! How could anyone expect an ordinary light dependent resistor photo cell to ‘see through a fingerti....
Controlled by indoor and outdoor temperature, Simple, high reliability design This circuit is intended to control a heating system or central heating plan....
If you have a motley collection of 12V batteries in varying states of health, this simple circuit will allow you to easily check their capacity. It s basi....
This circuit was designed to allow a laptop computer to be powered from a solar power setup. The computer requires 12V at 3.3A. The circuit is a linear re....
This circuit was designed as a warning flasher to alert road users to dangerous situations in the dark. Alternatively, it can act as a bicycle light (subj....
This inexpensive circuit can be connected to an air-conditioner/fridge or to any other sophisticated electrical appliance for its protection. Generally, c....
An interesting circuit of a bicycle horn based on a popular, low cost telecom ringer chip is described here. This circuit can be powered using the bicycle dynamo supply and does not require batteries, which need to be replaced frequently. The section....
To operate car audio (or video) system from household 230V AC mains supply, you need a DC adaptor. DC adapters available in the market are generally costl....
There are many circuits for low voltage regulators. For higher voltages, such as supplies for valve circuits, the situation is different. That s why we de....
This circuit is designed to switch on/off any home or industrial appliance by using the TV/DVD remote controller. The circuit can be operated up to a dist....
This homemade metal detector circuit will help you find objects composed of materials with relatively high magnetic permeability. It is not suitable for b....
Have you ever connected two PCs together via modems using a twisted pair cable and nothing happened? That s because the modems are expecting a phone line....
Potentially, headphone listening can be technically superior since room reflections are eliminated and the intimate contact between transducer and ear mea....
Here is the circuit diagram of IC Controlled Emergancy Light With Charger or simply 12V to 220V AC inverter circuit. The circuit shown here is that of the IC controlled emergency light. Its main features are: automatic switching-on of the light on mains....
This circuit was devised to switch power to a Peltier cooler in a vehicle. Power to the load from the vehicle s battery is switched by a SPDT relay while....
This remotely controlled watering system is both inexpensive and easy to expand. It is designed to operate in conjunction with a conventional watering tim....
Useful for liquids level detection and proximity devices, Up to 50 cm. range, optional relay operation This circuit is useful in liquids level or proximit....
This is a short-range light barrier for use as an intruder alarm in doorposts, etc. The 555 in the transmitter (Figure 1) oscillates at about 4.5 kHz, sup....
Firecrackers are normally ignited by using a matchstick or a candle. You have to run away quickly after igniting the fuse of the firecracker. This method....
This circuit can be built from readily available low-cost components, some of which may even be hiding in your junkbox! The indicated value of 22 ? for re....
This 555 timer circuit Remote control Jammer device it s useful when we need to block someone to use the remote control (children that change frequently t....
The infrared detector module (GP1U52X) (Radio Shack 276-137) provides a 5 volt TTL pulse train corresponding to the digital code to the button of the remote control. In the lower circuit, the module output normally low a signal and a positive going pulse....
This project sprang from the need to be able to remotely control audio-visual equipment placed inside cupboards. RF-based commercial units such as those u....
This add-on circuit enables remote switching on/off of battery-operated toy cars with the help of a TV/video remote control handset operating at 3040 kHz....
Here is a simple but inexpensive inverter for using a small soldering iron (25W, 35W, etc) In the absence of mains supply. It uses eight transistors and a....
Portable loads such as video cameras, halogen flood lights, electrical irons, hand drillers, grinders, and cutters are powered by connecting long 2- or 3-....
This is an Infrared beam breaking alarm ideal to use in entry or passages.It is based on the working of the popular IR sensor Module TSOP 1738 which sense....
Men in particular enjoy the convenience of television remote controls often to the annoyance of their female partners. Men apparently want to know what....
Using this circuit, audio musical notes can be generated and heard up to a distance of 10 metres. The circuit can be divided into two parts: IR music tran....
Turn ON or OFF electrical devices using remote control is not a new idea and you can find so many different devices doing that very well. For realization....
With many audio systems consisting of separate units, you ll often ?nd that due to economic reasons only the amplifier has a remote control receiver modul....
This small circuit is ideal for checking the basic operation of an infrared remote control unit. The circuit is based on the brilliantly simple idea of connecting a piezo buzzer directly to an IR receiver IC. This method is almost as simple as connecting a....
Many modern motherboards are equipped with an infrared data interface compliant with the IrDA standard, but this interface not very often used. However, i....
Two multivibrators with different frequencies can be built using the NAND gates of a 4011 IC. If the output of IC1. B is positive with respect to IC1. C, LED D1 is on. As the levels of IC1. A and IC1. D are exactly opposite, D2 is always on when D1 is off,....
This simple circuit proves to achieve surprisingly good results when used with the IRS/PDIF transmitter described elsewhere in this site. The IR receiver....
The best-known ways to transmit a digital audio signal (S/PDIF) are to use a standard 75? coaxial cable or Toslink optical modules with matching optical c....
3V Battery powered, Beeps after a fixed minutes delay This circuit was developed since a number of visitors of this website requested a timer capable of e....
Exhaust fan is an important component in kitchens. Here is a simple circuit to control kitchen fans by monitoring the ambient temperature. It is built aro....
A lambda probe (or oxygen sensor) can be found on the exhaust system of most cars running on unleaded fuel. Having reached its normal operating temperatur....
Protect your valuable laptop against theft using this miniature alarm generator. Fixed in-side the laptop case, it will sound a loud alarm when someone tr....
This circuit is a laser alarm system like the one we see in various movies. It uses a laser pointer beam to secure your valuables and property. Essentially, when the beam gets interrupted by a person, animal or object, the resistance of a photodiode will....
This circuit is built around a 555 timer using very few components. Since the circuit is very simple, even a novice can easily build it and use it as a co....
This automatic door opener can be made using readily available components. The electromagnetic relay at the output of this gadget can be used to control t....
In many projects use is made of alphanumeric LCDs that are driven internally by Hitachi s industry-standard HD44780 controller. These displays can be driv....