Top Circuits Page 237
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Optimize the layout of the MAX16974/MAX16975/MAX16976 high-performance DC-DC converters, standard buck controllers designed for automotive applications....
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The micropower circuit provides shutdown, power-up, and low-battery lockout functions automatically, without the need for software or operator control....
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Presented in this letter is a very low-power monolithic 1.9GHz silicon LNA which draws a total current of 1.75mA including bias circuit....
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The following discussion helps you choose the best microprocessor supervisor IC suited to your application, and offers solutions for many common microprocessor supervisory problems....
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Application note on how to design linear and switch-mode (switching dc-dc converter current source) battery charger applications that require external microcontrollers and related system-level issues for notebook computers....
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Presents a family of IF voltage-controlled oscillators (VCOs) to cover the frequency range from 45MHz to 650MHz. The ICs are in 6-pin SOT23 packages. Phase noise is -100dBc/Hz for the MAX2608 at 300MHz to 500MHz. An off-chip inductor sets the operating....
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Using a low-cost high-side precision current monitor to prevent excessive load currents from damaging power supplies....
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The following article is a follow-up application note to `Defining and Testing Dynamic Parameters in High-Speed ADCs, Part 1`. It details test conditions and setup recommendations to efficiently measure the dynamic performance parameters of high-spee....
-
Article compares high- and low-side amplifiers to measure battery charging currents, recommends selection criteria for current-sense resistors, and describes a high-voltage circuit breaker for overcurrent protection....
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A 50W isolated forward-converter switching supply for telecom applications is described. Most aspects of the design are discussed....
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A design example for a portable data acquisition system is offered that greatly simplifies the circuit design task....
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-
Power-supply controller has staggered voltage-output sequencing. Four voltage outputs turn on simultaneously for voltage tracking; two outputs for core and I/O supplies during power-up and two outputs for line driver supplies where tracking is not critical....
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An integrated circuit`s response to fast transients on its input supply is often an important measurement to take. If the device under test (DUT) is a micro-power device and doesn`t require an input bypass capacitor, simply drive the power-supply input with....
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This application note presents the component values and measured performance for the MAX2681 mixer IC when tuned for GPS operation at 1575MHz....
-
Design a 32kHz wide supply range oscillator with a low-power comparator, a reference and crystal oscillator....
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Overview: The DS8500 is a single-chip modem with Highway Addressable Remote Transducer (HART®) capabilities and satisfies the HART physical layer requirements. The device integrates the modulation and demodulation of the 1200Hz/2200Hz FSK signa....
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Overview: The MAX34446 data logger for power supplies can monitor voltages for overvoltage and undervoltage, as well as for overcurrent conditions and overtemperature conditions. The device constantly checks for userprogrammable thresholds; when th....
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A 200-watt class-E AM transmitter used for non-sanctioned broadcasting on 1710 kHz. Negative peak limiter, over-modulation indicator, linear scale directional wattmeter, power supply and antenna circuits (schematic diagram) are also shown....
-
The material in this section shows how we built the Twist-Shift system for VHF using commonly available (and cheap) surplus land mobile VHF transceivers modified to operate on the 2-meter ham band. The radios we used were the 100-watt Motorola SyntorX model.....
-
Before Light-Emitting Diodes (LEDs) and Liquid Crystal Displays (LCDs) the electronic industry used cold-cathode tubes for displaying numbers, symbols and even characters. Even though they are called "tubes" they differ from "radio tubes" by having no heater....
-
Fact is that the Nixies need a particular cathode current to entirely light up the cathode at all. If you just reduce the anode voltage the current through the anode resistor drops and so does the cathode current. Up to a certain point where the cathode is....
-
This web page describes how to install and use my ezlog data logging software. This software allows you to measure when different events happened, allowing you to synchronise the timing of different stimuli. Specifically, my software is designed to get a....
-
This radio was purchased on eBay as not working, and obviously missing all tubes and tube shields. I was told that it is a relatively rare set, being a Philco and a 32 volt farm radio. Most 32 volt radios I have seen were made by Delco, Silvertone, Coronado....
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This project was inspired by a circuit that a friend of mine, Simon Field, over at Scitoys. com showed me. He had built a very simple transmitter circuit out of a 1Mhz "can" oscillator and a serial connector (see it here ) In his circuit he used a computer....
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The. 01uf monolithic capacitors will be marked `103 K` and the 15pf monolithic capacitors are marked `15 J`. It is very important that you don`t confuse the two. DO NOT take either the MOSFETs or the Integrated circuits off their protective static containers....
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You should notice that the opto-isolator LEDs are connected to three wires labeled "FWD", "REV", and "ENA*. " These wires deserve a bit of explanation. The FWD, REV, and ENA* lines are the interface between the bridge and the microprocessor. You will notice....
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Because these transistors are a complementary pair, the circuit using them is very symmetrical. The upper right and upper left corners of the H-bridge are called "sources. " This name originates from their function which is to be a source of current for the....
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-
Very first PIC program using C language. Explains how to blink a single LED using PIC microcontroller with C program. Start learning C programming for PIC here....
-
How to build and use simple PIC programmer with very easy to find and extremely low cost parts. Total cost to build programmer is less than 1.5USD....
-
The actual anti-theft system is equipped with two frequency siren and connected to a vehicles immobilizer system. But in the laboratory simulation model; the change of operating modes, triggering of the siren and cutting off of the fuel supply to the engine....
-
Here we are working on small microcontrollers like PICs and Atmel series, which are operating from 5V and require less than 100mA for complete system typically. There are some PICs operate from lower voltages like 3. 3V, but the principals for power supply....
-
I had the prototype working on the breadboard, I built another unit on a piece of Radio Shack Protoboard for use in the field. It came together in only a couple of hours, and again, worked the first time (I must be living right lately). This more rugged....
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For the shorter wavelength VHF and UHF bands it`s more practical to construct more complex antennas such as a single band Slim Jim or Yagis; I`ve had a go at a few such projects. Other projects will be an electronic unit of some kind: For the Intermediate....
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THE OP-AMP: The Op-Amp used for the signal meter circuit is a TL061. An LF351 works just as well, however and has the same pin layout. If you have a TL062 or similar the differing pin-outs are shown below so that you can design your circuit board....
-
A small Medium Wave antenna from a walkman with digital radio and a variable capacitor (VC) with two sections connected in parallel from an old russian radio (2x280pF). I read on the Internet that if you live in an area with strong signals and you want to....
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-
We used buffer IC`s (7417, 7414) to isolate the signals to and from the Arduino. This protected the board, and provided power for external devices without drawing it from the Arduino. An H-bridge can be thought of in much the same way. It is the interface....
-
One of the simplest ways to get a motor to turn in both directions is by using a double-pole, double-throw (DPDT) relay. Along with the relay, this hookup requires two transistors and two Stamp pins, one for on/off control and the other for direction....
-
The strategy is to get the circuit going in stages, testing each part as you go. Once everything is wired correctly and can be either controlled or read by the computer correctly, then you can write the main program with confidence that all the pieces are....
-
-
My beacon is using now a simple CW keying QRSS3 10140. 020 khz, power is 20 milliwatt. I`m using a PIC program PicBeacon di Ik2pcb. Click here for the reception report The idea of making this beacon start from two project, one is the Hans G0GPL QRSS Junkbox....
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A simple circuit for monitoring the fuel level in vehicles. It gives an audiovisual indication when the fuel level drops alarmingly below the reserve level, helping you to read more †’..
-
A noise generator with a wideband output signal is always handy to have around when you`re adjusting receivers and other types of HF equipment. Simple RF Noise Source Circuit Diagram: read more †’..
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The LM1830 fluid detector IC from National Semiconduc tor is designed to be able to detect the presence of fluids using a probe. This chip requires a relatively high supply voltage and is not the most frugal power consumer. It is also quite specialised so....
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An audio amplifier based on the TDA7240 IC from ST Microelectronics. The LM1875 is a monolithic power amplifier offering very low distortion and high quality performance for consumer audio applications. This circuit of audio amplifier based IC TDA7240 can....
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This circuit is similar to the one above but uses positive feedback to get a little more amplitude to the speaker. I copied it from a small 5 transistor radio that uses a 25 ohm speaker. In the circuit above, the load resistor for the driver transistor is....
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This audio processor circuit features the SSM2045 IC which was developed specially for electronic music applications and the 741 opamp IC. The circuit is configured as a low pass filter with a DC voltage control for gain. The input signal is set to a working....
-
The circuit consists of a sensitive LM358 based comparator, IC1A, which keeps monostable IC2A (a 4538) triggered as long as an audio signal is detected at the input. Via coupling capacitor C1 the circuit takes its input signal from the hot` side of the....
-
The LM1036 is a DC controlled tone (bass/treble), volume and balance circuit for stereo applications in car radio, TV and audio systems. An additional control input allows loudness compensation to be simply effected. Four control inputs provide control of....
-
A simple ambit for converting an audio arresting (such as one that comes from the apostle terminals of a CD player). The ambit basically consists of a buffer/amplifier date and three clarify circuits: a high-pass filter, a mid-pass filter, and a low-pass....
-
The TDA7294 is a Hi-Fi amplifier and can give 100W RMS but with 10% distortion. Supplying 30 Volts you can have 50 Watts RMS with 1% distortion. Frequency range start at 16Hz and can reach 100KHz. Make sure you are using good heatsink. The chip supports mute....
-
The circuit described below monitors your car`s brake lights, and indicates by a light emiting diode whether they both function correctly. In that sense, it can save you money by preventing your being fined for driving with defective brake lights, and it....
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-
A USB port, in practice, is capable of supplying more than 100 mA of continuous electric current at 5V to the peripherals which are hooked up with the bus. So a USB port could be utilized, without having any problems, for powering 5V DC operated tiny....
-
The circuit described below monitors your car`s brake lights, and indicates by a light emiting diode 12V whether they both function correctly. In that sense, it can save you money by preventing your being fined for driving with defective brake lights, and it....
-
-
This circuit uses the popular and easy to find LM3914 IC. This IC is very simple to drive, needs no voltage regulators (it has a built in voltage regulator) and can be powered from almost every source. When the test button is pressed, the Car battery voltage....
-
A novel use of solar cells makes positioning your car in the garage rather easier than old tyres, a mirror, or a chalk mark. The six solar cells in figure 1 serve as power supply and as proximity sensor. They are commercially available at relative low cost.....
-
The circuit is build around an stable multivibrator using NE 555. Here the output at pin 3 remains high for a time period set by R2, and low for a time period set by R3. The low output pulse drives the transistor pair to drive the wiper motor to make one....
-
This low cost bass treble circuit consists of some capacitors, resistors, and two T/C pot for BASS and TREBLE control. this circuit can be made without even a veroboard. You just solder components as this circuit network is not so complex. It has only....
-
-
-
A simple battery charger that disconnects the battery when charge voltage reaches its nominal voltage and reconnects when battery voltage falls below a predefined level, can be designed using this circuit diagram. A fraction of the battery voltage is taken....
-
-
Many electronic projects call for a timebase generator, accurate to a second or so. One way of producing this is with a microcontroller, quartz crystal and some software. But a far cheaper and simpler approach is to recycle an old analogue quartz clock.....
-
This type of infrared proximity circuit is widely used as an electric switch where physical contact is not desired for hygiene purpose. For example, we commonly see use of infrared proximity sensors on public drinking fountains and in public washrooms. The....
Optimize the layout of the MAX16974/MAX16975/MAX16976 high-performance DC-DC converters, standard buck controllers designed for automotive applications....
The micropower circuit provides shutdown, power-up, and low-battery lockout functions automatically, without the need for software or operator control....
Presented in this letter is a very low-power monolithic 1.9GHz silicon LNA which draws a total current of 1.75mA including bias circuit....
The following discussion helps you choose the best microprocessor supervisor IC suited to your application, and offers solutions for many common microprocessor supervisory problems....
Application note on how to design linear and switch-mode (switching dc-dc converter current source) battery charger applications that require external microcontrollers and related system-level issues for notebook computers....
Presents a family of IF voltage-controlled oscillators (VCOs) to cover the frequency range from 45MHz to 650MHz. The ICs are in 6-pin SOT23 packages. Phase noise is -100dBc/Hz for the MAX2608 at 300MHz to 500MHz. An off-chip inductor sets the operating....
Using a low-cost high-side precision current monitor to prevent excessive load currents from damaging power supplies....
The following article is a follow-up application note to `Defining and Testing Dynamic Parameters in High-Speed ADCs, Part 1`. It details test conditions and setup recommendations to efficiently measure the dynamic performance parameters of high-spee....
Article compares high- and low-side amplifiers to measure battery charging currents, recommends selection criteria for current-sense resistors, and describes a high-voltage circuit breaker for overcurrent protection....
A 50W isolated forward-converter switching supply for telecom applications is described. Most aspects of the design are discussed....
A design example for a portable data acquisition system is offered that greatly simplifies the circuit design task....
Power-supply controller has staggered voltage-output sequencing. Four voltage outputs turn on simultaneously for voltage tracking; two outputs for core and I/O supplies during power-up and two outputs for line driver supplies where tracking is not critical....
An integrated circuit`s response to fast transients on its input supply is often an important measurement to take. If the device under test (DUT) is a micro-power device and doesn`t require an input bypass capacitor, simply drive the power-supply input with....
This application note presents the component values and measured performance for the MAX2681 mixer IC when tuned for GPS operation at 1575MHz....
Design a 32kHz wide supply range oscillator with a low-power comparator, a reference and crystal oscillator....
Overview: The DS8500 is a single-chip modem with Highway Addressable Remote Transducer (HART®) capabilities and satisfies the HART physical layer requirements. The device integrates the modulation and demodulation of the 1200Hz/2200Hz FSK signa....
Overview: The MAX34446 data logger for power supplies can monitor voltages for overvoltage and undervoltage, as well as for overcurrent conditions and overtemperature conditions. The device constantly checks for userprogrammable thresholds; when th....
A 200-watt class-E AM transmitter used for non-sanctioned broadcasting on 1710 kHz. Negative peak limiter, over-modulation indicator, linear scale directional wattmeter, power supply and antenna circuits (schematic diagram) are also shown....
The material in this section shows how we built the Twist-Shift system for VHF using commonly available (and cheap) surplus land mobile VHF transceivers modified to operate on the 2-meter ham band. The radios we used were the 100-watt Motorola SyntorX model.....
Before Light-Emitting Diodes (LEDs) and Liquid Crystal Displays (LCDs) the electronic industry used cold-cathode tubes for displaying numbers, symbols and even characters. Even though they are called "tubes" they differ from "radio tubes" by having no heater....
Fact is that the Nixies need a particular cathode current to entirely light up the cathode at all. If you just reduce the anode voltage the current through the anode resistor drops and so does the cathode current. Up to a certain point where the cathode is....
This web page describes how to install and use my ezlog data logging software. This software allows you to measure when different events happened, allowing you to synchronise the timing of different stimuli. Specifically, my software is designed to get a....
This radio was purchased on eBay as not working, and obviously missing all tubes and tube shields. I was told that it is a relatively rare set, being a Philco and a 32 volt farm radio. Most 32 volt radios I have seen were made by Delco, Silvertone, Coronado....
This project was inspired by a circuit that a friend of mine, Simon Field, over at Scitoys. com showed me. He had built a very simple transmitter circuit out of a 1Mhz "can" oscillator and a serial connector (see it here ) In his circuit he used a computer....
The. 01uf monolithic capacitors will be marked `103 K` and the 15pf monolithic capacitors are marked `15 J`. It is very important that you don`t confuse the two. DO NOT take either the MOSFETs or the Integrated circuits off their protective static containers....
You should notice that the opto-isolator LEDs are connected to three wires labeled "FWD", "REV", and "ENA*. " These wires deserve a bit of explanation. The FWD, REV, and ENA* lines are the interface between the bridge and the microprocessor. You will notice....
Because these transistors are a complementary pair, the circuit using them is very symmetrical. The upper right and upper left corners of the H-bridge are called "sources. " This name originates from their function which is to be a source of current for the....
Very first PIC program using C language. Explains how to blink a single LED using PIC microcontroller with C program. Start learning C programming for PIC here....
How to build and use simple PIC programmer with very easy to find and extremely low cost parts. Total cost to build programmer is less than 1.5USD....
The actual anti-theft system is equipped with two frequency siren and connected to a vehicles immobilizer system. But in the laboratory simulation model; the change of operating modes, triggering of the siren and cutting off of the fuel supply to the engine....
Here we are working on small microcontrollers like PICs and Atmel series, which are operating from 5V and require less than 100mA for complete system typically. There are some PICs operate from lower voltages like 3. 3V, but the principals for power supply....
I had the prototype working on the breadboard, I built another unit on a piece of Radio Shack Protoboard for use in the field. It came together in only a couple of hours, and again, worked the first time (I must be living right lately). This more rugged....
For the shorter wavelength VHF and UHF bands it`s more practical to construct more complex antennas such as a single band Slim Jim or Yagis; I`ve had a go at a few such projects. Other projects will be an electronic unit of some kind: For the Intermediate....
THE OP-AMP: The Op-Amp used for the signal meter circuit is a TL061. An LF351 works just as well, however and has the same pin layout. If you have a TL062 or similar the differing pin-outs are shown below so that you can design your circuit board....
A small Medium Wave antenna from a walkman with digital radio and a variable capacitor (VC) with two sections connected in parallel from an old russian radio (2x280pF). I read on the Internet that if you live in an area with strong signals and you want to....
We used buffer IC`s (7417, 7414) to isolate the signals to and from the Arduino. This protected the board, and provided power for external devices without drawing it from the Arduino. An H-bridge can be thought of in much the same way. It is the interface....
One of the simplest ways to get a motor to turn in both directions is by using a double-pole, double-throw (DPDT) relay. Along with the relay, this hookup requires two transistors and two Stamp pins, one for on/off control and the other for direction....
The strategy is to get the circuit going in stages, testing each part as you go. Once everything is wired correctly and can be either controlled or read by the computer correctly, then you can write the main program with confidence that all the pieces are....
My beacon is using now a simple CW keying QRSS3 10140. 020 khz, power is 20 milliwatt. I`m using a PIC program PicBeacon di Ik2pcb. Click here for the reception report The idea of making this beacon start from two project, one is the Hans G0GPL QRSS Junkbox....
A simple circuit for monitoring the fuel level in vehicles. It gives an audiovisual indication when the fuel level drops alarmingly below the reserve level, helping you to read more †’..
A noise generator with a wideband output signal is always handy to have around when you`re adjusting receivers and other types of HF equipment. Simple RF Noise Source Circuit Diagram: read more †’..
The LM1830 fluid detector IC from National Semiconduc tor is designed to be able to detect the presence of fluids using a probe. This chip requires a relatively high supply voltage and is not the most frugal power consumer. It is also quite specialised so....
An audio amplifier based on the TDA7240 IC from ST Microelectronics. The LM1875 is a monolithic power amplifier offering very low distortion and high quality performance for consumer audio applications. This circuit of audio amplifier based IC TDA7240 can....
This circuit is similar to the one above but uses positive feedback to get a little more amplitude to the speaker. I copied it from a small 5 transistor radio that uses a 25 ohm speaker. In the circuit above, the load resistor for the driver transistor is....
This audio processor circuit features the SSM2045 IC which was developed specially for electronic music applications and the 741 opamp IC. The circuit is configured as a low pass filter with a DC voltage control for gain. The input signal is set to a working....
The circuit consists of a sensitive LM358 based comparator, IC1A, which keeps monostable IC2A (a 4538) triggered as long as an audio signal is detected at the input. Via coupling capacitor C1 the circuit takes its input signal from the hot` side of the....
The LM1036 is a DC controlled tone (bass/treble), volume and balance circuit for stereo applications in car radio, TV and audio systems. An additional control input allows loudness compensation to be simply effected. Four control inputs provide control of....
A simple ambit for converting an audio arresting (such as one that comes from the apostle terminals of a CD player). The ambit basically consists of a buffer/amplifier date and three clarify circuits: a high-pass filter, a mid-pass filter, and a low-pass....
The TDA7294 is a Hi-Fi amplifier and can give 100W RMS but with 10% distortion. Supplying 30 Volts you can have 50 Watts RMS with 1% distortion. Frequency range start at 16Hz and can reach 100KHz. Make sure you are using good heatsink. The chip supports mute....
The circuit described below monitors your car`s brake lights, and indicates by a light emiting diode whether they both function correctly. In that sense, it can save you money by preventing your being fined for driving with defective brake lights, and it....
A USB port, in practice, is capable of supplying more than 100 mA of continuous electric current at 5V to the peripherals which are hooked up with the bus. So a USB port could be utilized, without having any problems, for powering 5V DC operated tiny....
The circuit described below monitors your car`s brake lights, and indicates by a light emiting diode 12V whether they both function correctly. In that sense, it can save you money by preventing your being fined for driving with defective brake lights, and it....
This circuit uses the popular and easy to find LM3914 IC. This IC is very simple to drive, needs no voltage regulators (it has a built in voltage regulator) and can be powered from almost every source. When the test button is pressed, the Car battery voltage....
A novel use of solar cells makes positioning your car in the garage rather easier than old tyres, a mirror, or a chalk mark. The six solar cells in figure 1 serve as power supply and as proximity sensor. They are commercially available at relative low cost.....
The circuit is build around an stable multivibrator using NE 555. Here the output at pin 3 remains high for a time period set by R2, and low for a time period set by R3. The low output pulse drives the transistor pair to drive the wiper motor to make one....
This low cost bass treble circuit consists of some capacitors, resistors, and two T/C pot for BASS and TREBLE control. this circuit can be made without even a veroboard. You just solder components as this circuit network is not so complex. It has only....
A simple battery charger that disconnects the battery when charge voltage reaches its nominal voltage and reconnects when battery voltage falls below a predefined level, can be designed using this circuit diagram. A fraction of the battery voltage is taken....
Many electronic projects call for a timebase generator, accurate to a second or so. One way of producing this is with a microcontroller, quartz crystal and some software. But a far cheaper and simpler approach is to recycle an old analogue quartz clock.....
This type of infrared proximity circuit is widely used as an electric switch where physical contact is not desired for hygiene purpose. For example, we commonly see use of infrared proximity sensors on public drinking fountains and in public washrooms. The....
