Questions tagged [light-sensor]

The Light Sensor is a passive devices that convert this “light energy” whether visible or in the infra-red parts of the spectrum into an electrical signal output.

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3answers
68 views

I'm making a simple dark sensor project with a light dependent resistor (LDR) and I want to replace the LED with a buzzer but it doesn't work

I replaced the resistors with small ones to give the buzzer more current,but itstill doesn't work. I checked my buzzer and it's working fine. The circuit works perfecly with the LED in the breadboard ...
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1answer
25 views

Software I2C and VL6180

Hell, I'm trying to use the following sensor VL6180 with software I2C on PIC18F2458 running at 4Mhz, with USB functionality. Currently the sensor doesn't work in terms of sending measurmenet, it can ...
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2answers
93 views

Live plant as a touch switch

I’m a Jack of all trades sort of guy but have basically zero electrical knowledge.. That being said.. I want to use a live.. real plant...to turn on and off a light. I tried a touch switch replacement ...
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0answers
32 views

Interfacing Arduino with TSL235 (light to frequency converter)

I am working on an Arduino based circuit that uses light to frequency converter (TSL235) to trigger a buzzer when there is an intensity change in the ambient light (for example when a car is pointing ...
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4answers
127 views

Light sensor detecting when the lights turns on AND when the light turns off

I would like to create a circuit using photodiode that detects when the lights turn on AND when the lights turn off. The output should look something like that: I want to create the simplest possible ...
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2answers
52 views

555 darkness latch timer

I found a circuit to do what I thought I wanted it to do. I want an LED to turn on for a few seconds when an LDR detects darkness. The circuit works perfectly but now, of course, if the light source ...
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0answers
28 views

Using LEDs as light sensor - how to level shift 0.2 V logic up to 3.3V threshold

I have a reel of punched paper tape (https://commons.wikimedia.org/wiki/File:PaperTapes-5and8Hole.jpg) and I would like to design a simple optical circuit that can read the binary values from it using ...
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1answer
54 views

Which optical sensor to detect polypropylene wipes pass by?

Which sensor should I use to detect that a polypropylene sheet (light shines through) has moved past a certain point? Would be nice if it could easily connect to an Arduino.
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1answer
52 views

Why does CNY70 output peak at a distance only?

I am using the CNY70 sensor similar as in Understanding the CNY70 Reflective Optical Sensor (FTR: V=3.3V (instead of 5V) R=1k (instead of 200Ω) and X=10k putting the output voltage in the range of 0–0....
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6answers
4k views

Why aren't garage door sensors retroflective on one end?

Seems like they should be a transceiver + retroreflector, not transmitter + receiver pair. Is there a cost or safety reason for this?
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2answers
144 views

Reflective optical sensor

I am working on a project that uses a TCRT5000 reflective optical sensor. Sensor datasheet is here I tested this sensor in a room, the voltage at the output pin is high it is above 2.5V. While ...
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0answers
59 views

Converting the 0-10V output of a PMT to a +- 10V dynamic range

I am trying to convert the output of a photomultiplier tube module (Hamamatsu HC120) which ranges from 0 to 10V to +-10V in order to fit the full dynamic range of a ADC (MCC USB-205). To do so, I've ...
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2answers
222 views

Can light damage a monitor/screen

I was reading some posts about how light can damage a camera by heating it up its internal components? Link: Can camera sensors be damaged by light? If I shine a 150-lumen flashlight at a monitor or ...
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1answer
65 views

Make shed light come on, if dark outside and door is open (with NPN and hall-effect sensor) [closed]

I recently purchased a new shed with a polycarb roof. At night, when I enter the shed, I'd like a light that comes on (but not during the day!). I'm trying to find a way for the light to switch on, ...
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1answer
56 views

Night light circuit wih switching bulbs

How can I connect a night light circuit such that one bulb is lit up on a sunny day and one is only lit up at night so that the two lights don't light up simultaneously? Also, can I use a SPDT switch ...
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1answer
54 views

Difference between AGC and AGAIN

I'm going through an AMS optical sensor data sheet (AS7341) and keep seeing an "AGAIN" setting and can't figure out what it is. At first I thought that it was an Automatic Gain Control, but it doesn't ...
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4answers
2k views

Will a 950 nm IR emitter work with a 870 nm phototransistor?

I'm planning to build a simple IR light barrier across a distance of 15 mm. I plan to use this receiver with this emitter. The reason is to have some SMD PNP capable components. The emitter and ...
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2answers
237 views

How to build fast visible light detector

I need a circuit which can detect flickering of light too fast. I have Digital LDR Module which is too slow can I replace LDR with L14G2. Digital LDR Module - Digital LDR Circuit - Can we ...
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1answer
82 views

DIY solar tracking system without any sensors

I'm building a tracking system for my university project. We will use two solar panels, one without tracking system and other one with tracking system and see the results if it's worthed or not. But ...
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1answer
84 views

Best sensor to measure light intensity in open room

I am working on a project to understand how robot localization is effected by light levels. I am wanting to build a circuit which can be mounted on a small robot near the camera and can determine lux ...
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1answer
99 views

Converting Battery Operated Motion Sensor Light to AC Powered

I have converted many battery powered devices to AC adapter in the past. This time around I am using a Motion Sensor light which takes 4 C batteries and is used to light a closet. When I connect a ...
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0answers
74 views

Is ok to use a CMOS Analog multiplexer with voltage from a sensor as an input?

So, I got an analog circuit with an IR sensor that generates a voltage in output. The voltage is a measure that must be read with a microcontroller (I use Arduino Zero). This is the sensor. As you ...
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2answers
94 views

Is there a way to measure or infer the color of a material from a distance (~2m), without using visible light?

I've recently started working on a graphics/SLAM project. We've encountered a problem that requires us to measure or infer the color / spectral reflectance (and ideally albedo) of points on objects in ...
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5answers
2k views

Thin wall to block LED light from hitting photodiode?

I'm designing a small heart rate sensor using green smd LEDs and a photodiode. The photodiode needs to measure the reflected light, and not direct light from the LEDs. The LEDs are near the perimeter ...
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1answer
64 views

IR Light Transmission Delay Error

The following circuit consists of two IR (Infra-Red) LED diodes; one as light transmitter (IR1) and other as light receiver (IR2). They are spaced for approximately 4 cm, so distance is not the issue ...
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1answer
793 views

555 timer delay circuit + light sensor?

I am quite new to electronics and I would like to combine these 2 circuits together so that during complete darkness on the LDR, the LED would turn on instantly and when light falls on the LDR there ...
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1answer
206 views

How to filter out certain wavelengths of light [closed]

I am trying to filter out certain wavelengths of light and I was wondering if there is a way that you can filter them out. I am using Silicon Photomultipliers (Linked below) and I only want to detect ...
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2answers
151 views

Light sensors sensitive enough to detect for PWM from CF and LEDs?

I have an extreme sensitivity to PWM light sources such as computer screens and light bulbs. This can make it very challenging to make a purchase as I end up having to do lots of guesswork with ...
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3answers
158 views

dc voltage control for LED lights?

I'm looking for a little bit of help on a project I'm working on. I need to find some way to make led light bars (18w and 120w) to automatically start out dim and gradually brighten to full ...
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2answers
533 views

Very low current (<10 microamps) darkness detector circuit that turns off in light

I've made a device that lights an LED at a very low current (<10 microamps) as a very dim indicator for use in the dark. At its simplest, the circuit is a 3V coin battery + resistor (300K-1M ...
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1answer
105 views

Phototransistor and Photodiodes capacitances when some in an array sense light

I'm using phototransistors to sense low speed data (about 7 bits a second). With one phototransistor and a 300K resistor, I found my sweet spot and can transmit correct data with lazer. I find if the ...
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1answer
99 views

Need a sensor for detecting the presence of someone like a door sensor we have in lifts/elevators

Door sensors used in elevators/lifts are very expensive and my budget is not that much. But I need a similar mechanism or solution to detect the presence of someone if he/she is standing in the given ...
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1answer
326 views

How to connect a 2 pin photodiode?

Initially, I have used 3 pin photodiodes, where the anode is connected to the resistor and has a wire which goes to group and the other goes to an analogue input to read the voltage. The cathode is ...
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4answers
2k views

How to tell how sensitive a photodiode is?

I am looking to buy some new photodiodes for a project. Currently, I have been using expensive photodiodes with a picosecond level rise and fall time and a very small area to pick up light. The ...
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1answer
80 views

Ultraviolet sensor response curve

I did a search on "ultraviolet sensors" in this forum, and came up with only three results, so, it appears, that this has not been asked before. I have a hand-held ultraviolet light sensor from ...
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3answers
302 views

Photodiode in photoconductive vs photovolatic configuration

I want to use a photodiode to measure light intensity, but I am not sure if the photodiode should be used in photoconductive or photovoltaic mode. From my understanding the photovoltaic ...
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2answers
199 views

VL6180X ALS values soo small

I have bought VL6180X proximity sensor on breakout (Aliexpress) originally designed for use with arduino. I have tried it use with Raspberry Pi and STM32 (on STM32F429 discovery board). Sensor is in ...
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3answers
827 views

How fast can we measure using IR sensors

Supposing I have an repeatedly object passing through IR sensors and I am looking at the output waveform. What is the maximum frequency the output waveform can have? I think this maybe related to the ...
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1answer
799 views

Which one is better to build lux meter, either LDR or photodiode?

I want to add the lux meter to my application. My controller works with 3.3V and ADC max reading voltage is 1.2Vref. I tried with LDR but I'm not able to get accurate values and the values also not ...
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1answer
669 views

Sensor to distinguish between daylight and artificial light in a room?

is there a way to distinguish between daylight and artificial light in a room? I'm thinking my options are a light intensity sensor or a color temperature sensor. The sunlight is supposed to be much ...
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1answer
53 views

Day-Light Sensing LED Light [closed]

I am looking for an example of a day-light sensing LED light, similar to https://www.evilmadscientist.com/2007/a-simple-and-cheap-dark-detecting-led-circuit/ but instead of turning on when dark, I ...
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1answer
149 views

Relative responisivity of the VEML6040

I'm currently working a project involving the VEML6040 color sensor (Link to application note). I am reading through the application note and stumbled on the graph depicted below. As far as i ...
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2answers
125 views

How to measure body temprature and HBR with just one IR transmitter and receiver

I want to measure body temperature and heartbeat rate only with a IR receiver and transmitter. How could I do that? Is it an accurate method? Or I have to use IR temperature sensor for this.
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1answer
83 views

How can you figure out what encoded signal my IR emitter should put out to register a hit on a laser tag gun?

I am using a 38kHz IR emitter, I've taken out the IR receivers on these guns and experimented to see if I am able to transmit a signal, it's working fine, however when I connect the IR sensor back in, ...
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3answers
524 views

How to control the brightness of an AC light bulb with the instant level of noise nearby

The device I want to make is simple to describe: a big red lightbulb, connected to the AC 110 / 220 V, stays dark when it's quiet in the room, starts lighting up somewhat if there's a moderate level ...
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1answer
83 views

Why popular line detection use Infrared(IR) based sensor? [closed]

Popular line sensor use IR LED as transmitter and IR photodiode as receiver to distinguish reflective color such as white and less reflective color like black. Consider that infrared LED is hard to ...
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2answers
182 views

Switch triggered by flashing light

I'd like a simple switch that triggers when a flashing light is detected. Purpose is to open gate by flashing car headlights (say 3 times). I have looked at comparators and photoresistors and ...
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2answers
70 views

Simulating a pyroelectric sensor

I am building test rigs and need to trigger motion detectors remotely. I would also like to avoid using a light source. The devices I've encountered all use an Excelitas 968 pyroelectric sensor (http:/...
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3answers
133 views

Lux sensors with max. operating temperature of 90-100 deg C?

For my project, I need to observe the lux inside a double-pane window. Last time, I used 'Adafruit TSL2561 Digital Luminosity/Lux/Light Sensor Breakout'* but its recommended maximum operating ...
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1answer
170 views

Kid's night light

I would like to make a more reliable nightlight for my daughter. I was using cheap solar string lights but they just don't last long enough or get enough sun on that side of the house. So I've ...