# Questions tagged [photosensor]

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### Are there any commercially available dense linear photodiode arrays for the near-infrared range? [closed]

I am looking for a high-density linear array of photodiodes (photodetectors) for the NIR range. By high-density I mean it should have at least a few hundred and ideally over a thousand elements with a ...
• 103
79 views

### Procedure to express radiantion intensity of a LED in watts/cm^2 , given luminous intensity or total radiant power [closed]

I am calculating Responsivity of a PN junction photodiode by irradiating radiation from LED sources. For this purpose, I have two LEDs, one UV and another green LED. Note that LEDs are placed close to ...
47 views

### In this circuit, the light intensity sensor (LDR) only senses 3_2 cm. How can I improve the sensitivity of this sensor to reach 1m?

In this circuit, the light intensity sensor (LDR) only senses 3_2 cm. How can I improve the sensitivity of this sensor to reach 1m? https://ibb.co/c3X1NRS
1 vote
127 views

### Extracting two signals from a photosensor

I have a circuit that pulses two LEDs on and off at the same frequency but out of phase. I would like to find a hardware solution for using one sensor to measure separately the intensity from each ...
99 views

### Problem in sensor circuit using a Phototransistor for the Schmitt Trigger circuit

This is my Schmitt Trigger design, which trips at $2.3V$ and $1.7V$- Here, $$+V_{cc} = 9V$$ $$R1 = 51k \Omega$$ $$R2 = 22k \Omega$$ $$R3 = 330k \Omega$$ $V_{in}$ is a square-wave with 0-7V peak ...
65 views

### Reverse photosensor is activating an LED but won’t activate a motor

I am trying to use a photosensor in reverse so that it activates when it is dark instead of light. I am using a 2N222 transistor. I tested with an LED and it works fine, but when I use the same ...
69 views

### Connecting photoelectric sensor to Arduino for distance measurement

I've purchased some of these sensors"S15-PA-2-A00-NK" and I would like to use them as distance sensors to be read by an Arduino. I have no idea what type of signal the sensor even outputs or ...
50 views

### Photogate is unresponsive - no output signal

I am trying to use this photogate with my Arduino Pro Mini (5V.) I am having no luck getting any readings from it. I measured the voltage across the emitter and got 4.5V, which should be enough to ...
1 vote
86 views

### I want to register a small change of voltage of a photo sensing diode at bullet's speed

What I intend to do Estimate Accuracy of a Bullet Hit from the Bull's Eye: Use a row of light sensing diodes like BPW34 (or you suggest) spanning a feet vertically and horizontally or so with laser ...
531 views

### What is the "collector light current" of a phototransistor and how does it relate to the collector current?

I found the "collector light current" term in this datasheet (Vishay TEFT4300) but I can't find a definition for it on the internet nor figure out how it relates to the collector current. I ...
• 53
113 views

### HP C9017 Photosensor wire colors [closed]

I have at my disposal a photosensor (Optical encoder) with "C9017-80055", it has three cables: Black, Green, and yellow. I want to know the circuit (GND, VCC, output) to connect it with ...
• 5
222 views

### Trouble understanding OEM HP Sensor CB781-80006 circuit [closed]

I am having trouble understanding an OEM HP Sensor CB781-80006 circuit, I'm a beginner in electronics. Does anyone know to tell me what are the values ​​( VCC, GND, and outputs ) this sensor was ...
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44 views

### I can’t remember the name of that component

I’m looking for the name of the component that act like a relay but instead of using a coil to generate a magnetic field that moves the relay « arm » it uses a LED and a photosensor. It allows to ...
• 327
1 vote
75 views

### Current sensor that works in 0nA-250nA range?

Is there any current sensor capable of sense very low current ranges from 0nA to 250nA? I would need to sense the current produced by this photodiode: GVGR-S11SD (http://www.geni-uv.com/download/...
1 vote
187 views

### Need help with break beam sensors for an art installation

I've been commissioned to create a piece of public art that fuses technology, light, and sound. The final piece must have six beams that can be broken and trigger musical notes. My first idea was to ...
140 views

### Photo eye sensor signal wiring

I am trying to install a photo eye to use for a lay down bottle sensor. I wired in the power, it turns on the light on the sensor flags when triggered. But I’m not abel to trace where the signal is ...
1 vote
68 views

### Existence of input signal to LED at photodiode output

I try to make simple LED/photodiode circuit by arduino and 741 op amp. I used mid-IR LED by 200mA current and suitable photodiode for it. I wanted make pulsed signal by digital output of Arduino UNO ...
1 vote
54 views

### Color Sensor Range

From what I've seen in spec sheets for modern color sensors (as of late 2020), the optimum sensing range is generally on the scale of centimeters. I am curious about the physics that can explain this ...
• 11
88 views

### HP C8941 Photosensor operating voltage and circuit

I have at my disposal a photosensor (Optical encoder) with "C8941-80018", it has three cables: Black, Green, and Blue. I want to know the Operating voltage for this optical encoder and a ...
62 views

### Low precision flash detector

I'm interested in flash detection, what would be equivalent to 1000 FPS. High speed cameras that do this are too expensive and too heavy and provide too much information. In the long run I'm going to ...
• 578
145 views

### Detecting small AC current signal generated by phototransistor

I'm trying to detect a small AC signal (~10kHz) generated by a phototransistor on a magnitude of 10nA~1uA using the following circuit by converting the signal to voltage signal first and then filter ...
• 131
176 views

### How to Modify IR Auto-Close Circuit for Trash Can Lid

Just bought a new trash can with an automatic lid that I'm fairly happy with but there's one modification I'd like to make. If I place the trash can in a cabinet and close the door it detects the door ...
• 535
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### Phototube experiment with op amp

I'm working on an experiment to find Planck's constant with a phototube. I built the following circuit and pointed an LED light to the phototube in a dark room, but I had a few problems: When there ...
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563 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 ...
83 views

### Photo-multiplier Tube Pin Configuration

Pin configuration of a photo-multiplier tube (PMT) is presented in its manual as can be seen in the attached image. All dynodes have been related to specified pins (numbered circles in the image) ...
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1 vote
229 views

### HP C8941 Photosensor wire colors

I removed a photosensor from an OLD hp Inkject Printer. The photosensor is called "C8941-80018". I can't find any datasheet online. Does anyone know what wire color is what?
127 views

### What is the origin of multiplicative noise from a DSLR sensor?

I'm trying to understand the behavior of my DSLR camera sensor (Canon 80D). I've taken a picture of a gradient from top-right to bottom-left corners of a square. This square is positioned at the right-...
• 854
1 vote
246 views

### Solar Panel-Photocell Wiring

I am trying to help my dad with a project of his where were trying to build a lighthouse powered by solar panel in which it spins a motor at night and charges battery during the day. This is a DC ...
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537 views

### What options exist for a for low-latency (<1ms) photosensor?

I'm wanting to build a computer keyboard-to-display lag measuring tool using an Ardunio: User places the photosensor right-up to their computer monitor. User presses a button on the Ardunio. The ...
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61 views

### Is the charge accumulation linear in time for image sensors?

Reformulating the question: Does the rate of charge of the pixels photodiodes in an image sensor depends of the previous accumulated charge? The pixel sensor integrates light during a specific ...
• 103
119 views

### Infrared Sensor for drug detection [closed]

I saw that there has been a push to make a drug detector that can identify cannabis since it has been legalized. I was looking at mouser.com and found this ir sensor: https://www.mouser.com/...
• 103
66 views

### Pachislo Token Sensor Optical sensor replacement part#?

Pachislo Token Sensor Optical sensor As shown above I have a Pachislo Mazya Dynamite Kid's Machine which has a bad Token Sensor Booard. Can someone please advise on what a suitable replacement part ...
1 vote
532 views

### Convert a Dusk-to-dawn outlet device to Dawn-To-Dusk? [closed]

I recently purchased a Dusk-to-dawn outlet sensor (https://www.amazon.com/dp/B00002NB2X?ref_=pe_2640190_261118450_302_E_DDE_dt_1), but I'm wanting to convert this thing into a Dawn-to-Dusk device ...
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128 views

### Can linearity of photoreceptor be improved by calibration?

I am trying to determine if equipment I already have can be used to take a reading in mcd/m2, for a quality control test. I have a sensor which meets all the requirements listed in the standard test ...
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My CD player's infrared receiver for its remote control has failed. (The remote still works with a friend's identical player.) I'd like to buy a replacement receiver and solder it in. How do I ...
1 vote
209 views

### Driving Avalanche Photodiodes (PCBs)

I am using Avalanche Photodiodes and I was told that they use a much higher voltage then standard photodiodes and I was wondering if I need a High Voltage PCB to drive them? I am currently just using ...
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624 views

### Please explain this formula for the relationship between bandwidth and the temporal response of a photodetector

I am reading "Optoelectronic Sensors" by Didier Decoster and Joseph Harari. At section 1.8.2 they start explaining the relationship between rise time and bandwidth, and they give a very weird formula ...
1 vote
874 views

### How to find polarity of photo interrupter

I have scavenged some photo interrupters from multiple printers but I am trying to figure out the polarity and the voltage. I've tried searching up photo interrupter polarity but couldn't find ...
182 views

### Dusk dawn motor driver with polarity reversal

I'm trying to accomplish this. When a dusk dawn switch is on, drive a small DC motor for a few seconds and then stop. when the dusk dawn switch is turned back off, then turn a small DC motor THE ...
725 views

### Photodiode temperature compensation

The goal is to design a circuit that can accurately measure light intensity with little temperature dependency. Common application uses photodiodes to do so. Photodiodes can be measured either in ...
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1 vote
257 views

### Replacing obsolete photodarlington with phototransistor

I've got an old circuit design I need to replicate, function wise, to fit into an existing larger design. Logic I can usually handle, anything with transistors starts to get me lost. My strength is ...
• 11
638 views

### Photo-diode for a high-frequency tachometer

I intend to build a tachometer, which is capable of detecting rotations up to 1kHz (60 000 RPM). From the Internet I know that this is possible to do with a magnet and a Hall detector. However, I ...
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911 views

### Design of output stage for CNY70 reflective sensor

I have built the following circuit for a reflective sensor: The resistor $R_D$ has been given the value 200 $\Omega$ and the resistor $R_T$ is to be dimensioned. $V_{CC}$ is 5 V. I have ...
85 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 ...
69 views

### Why there is difference between image size and video resolution of a specific camera? [closed]

I was searching to buy a camera, but I saw in specs they wrote: 2MP(full hd) video recording 5MP image size Why the vido size is 2MP but image size is 5MP? How ...
1 vote
6k views

### How to increase sensitivity of Light Dependent Resistor (LDR) [closed]

I am using LDR sensor in my project. The source of light comes from the different colour of images. As we know, the spectrum of each colour is different and it will produce a different intensity of ...
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1 vote
1k views

### Detecting a very fast moving object with a photoelectric sensor

I want to use a photoelectric sensor to detect a ball that is moving past the sensor at 85mph, which also equals 136kph or 3800cm/sec. The ball is 7cm in diameter. If my logic is correct that means ...
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1 vote
702 views

### I need help in rewiring a chicken coop pop door

4 years ago I purchased an automatic chicken pop door for my coop. It is 12 volts and the door opens at dawn and shuts at dusk by means of a photosensor. It is a home built device that works quite ...
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1 vote