Questions tagged [light-sensor]

A passive device that converts light photons into an electrical signal output. Examples include photodiodes and photo transistors.

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Measuring ambient light intensity using BPW34 photodiode and TLC271ACP opamp

I've composed a schematic for measuring ambient light intensity using a BPW34 photo diode (Osram brand) and a TLC271ACP opamp. The output will be read using an ADC entrance of an MCU, so VDD = 5V here....
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I'm looking for a very sensitive photodiode [closed]

I'm working with a custom board that has a simple input to detect a closed switch, and I'm hoping to use it as a light sensor. I was thinking of just attaching a simple photodiode (Like this one: ...
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Light to Sound Device [closed]

I need a device I can put on a light externally to make a sound or alarm when it turns on. What device would this be? Or how would this be done simply without soldering?
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How to calculate value of voltage by light intensity?

I want to write the code to turn the LED on when the light intensity that falls on the photoresistor decreases. So in daylight LED is off, and when it's getting dark LED goes on. I know that ...
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Help in identifying IC

I'm trying to identify the 16 pin white IC shown in the picture but I couldn't find any IC with marking code similar to that. I'm not sure but the board which IC is assembled on may be related to a ...
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2 answers
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LED luminosity decreasing over time

I'm measuring an LED with a light sensor but I'm running into a problem where the LED's luminosity (lux) is decreasing over time. Confusing since this is a simple setup, I don't know if the LED's I'm ...
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4 answers
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What is a modulated optical sensor?

I was told to try out a modulated optical sensor as a better and more "robust" option than the usual (unmodulated) optical sensors, saying the modulated ones are less subject to interference....
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Convert flame sensor ADC value to wavelength

I am working on a fire detector project using a flame sensor. This sensor can detect IR light wavelength from 760-1100 nm using a YG1006 phototransistor. I have read that if the wavelength is bigger ...
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1 answer
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ATMega2561 - How to connect this ambient light sensor using 1-Wire?

I am trying to connect the following components to an AVR ATMega2561: 1-Wire Master Interface DS2484 datasheet here RGB Ambient Light Sensor APDS-9250 datasheet here I have already managed to ...
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1 answer
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How to manipulate a PIR sensor?

The passive infrared (PIR) motion sensor detects movement of infrared light sources with wavelengths ranging from 7 μm to 14 μm. Is there a way to make it detect below 10μm or to make it detect ...
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-3 votes
1 answer
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opamp dc comparator [closed]

simulate this circuit – Schematic created using CircuitLab I am trying to compare the voltages of the inverting and non-inverting terminal but no matter what input I put in, the voltages seem to ...
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How good are Time-Of-Fligt (light) sensors for measuring small objects?

I found this sensor VCNL4040 and it has the emitter angle and the sensor angle. Question: How good is a Time-Of-Flight (light) sensor to measure small objects that are 100mm away and about 20x20mm in ...
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How wide is IR-led light from VCNL4040?

I have an issue to solve. I'm going to measure an object that looks like this. My question is if the sensor VCNL4040 have a very wide spread light or very "laser-like" light that ...
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Light control switch protection

first post here so be kind :) disclaimer : I am not a professional and nor I have any engineering background, all this is part of a hobby. After fiddling for months with SonOff / Tasmota / MQTT / Home ...
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5 votes
2 answers
234 views

LED not outputting square wave signal

I'm working on a sensor similar to an oximeter that measures light attenuation through a medium. I have an LED on one side, and an IC photodiode with on-chip transimpedance amplifier (OPT101) on the ...
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Optical pulse sensor not producing a clean TTL pulse

I have two of these optical pulse sensors monitoring LEDs on my electric and solar meters - Optical Pulse Sensor - Github The first sensor outputs nice TTL pulses at 5V, the second sensor outputs ...
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APDS-9253 reads all data registers as 0

I'm trying to read data from an APDS-9253 with an xmega. My i2c bus is working because I'm reading other devices without any problem. From the datasheet it seems at power-up the sensor is not ...
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Can we program our smartphone camera to detect the frequency and time period of IR light?

My use case is this: I am emitting morse code using a sole IR light source, and I intend to detect the frequency and the time period of the light source using my smartphone camera. Can this be done?
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1 vote
2 answers
693 views

Simulating Photodiode sensor in LTspice

I am designing a current source that is going to control LED. With help of the DAC and microcontroller, I generate a voltage that goes to OP-amplifier, and afterward, I am opening my NMOS transistor. ...
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1 answer
202 views

Retrieving energy data from dali2 D4i memory bank (202) of a luminare

I'm trying to read the memory bank202 from a DALI-2 supported led luminary for energy consumption. it returns a value of zero. when i gone through the Dali part 252 energy reporting Doc. It asked me ...
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2 votes
1 answer
49 views

Meaning of two ADC channels in an LTR-559ALS-01 optical sensor

I am using an LTR-559ALS-01 optical sensor to read the level of ambient light. Everything works, but from the datasheet I can't make out why there are two analog channels for said reading. Both ...
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Can a solar cell based lux meter produce useful readings for ultraviolet light?

I was reading the question Safety Guidelines for Ultraviolet LEDs? about ultraviolet exposure, and realized that a solar cell can probably detect this, since solar cells can also detect visible light, ...
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1 answer
108 views

Light Sensor INT Pin function

I have a Light Sensor IC. There is an Interrupt pin. I can see the status of it on page 9. What is the high and low threshold exceed that they are mentioning in that table? Can someone tell me what ...
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Interpolation method for downsampling smartphone sensor data

I have a dataset containing lot of sensor measurements on Android smartphones, namely accelerometer, gyroscope and light sensor. The light sensor was sampled at a rate of 4 Hz and the accelerometer ...
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3 answers
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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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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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2 answers
307 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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0 votes
4 answers
193 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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2 answers
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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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1 vote
1 answer
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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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1 vote
1 answer
191 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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23 votes
6 answers
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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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3 votes
2 answers
530 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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1 vote
0 answers
139 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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1 vote
2 answers
629 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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1 answer
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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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-1 votes
1 answer
96 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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-3 votes
1 answer
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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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11 votes
4 answers
3k 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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2 answers
470 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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1 answer
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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 worth it or not. But ...
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1 answer
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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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0 votes
1 answer
218 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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0 votes
0 answers
101 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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1 vote
2 answers
104 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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4 votes
5 answers
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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0 votes
1 answer
97 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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3 votes
1 answer
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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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0 votes
1 answer
370 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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2 votes
2 answers
291 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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