Questions tagged [optical]

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BPSK vs PM-BPSK: conceptual clarity required

How PM-BPSK is different from BPSK? What would be the constellation diagram? I know information is sent on two different polarisations but does this mean two different signals can be sent at a single ...
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Why is channel DC gain sufficient to model optical wireless communications?

I came across the following question at ResearchGate, but I fail to comprehend the answer to it. The question states: Why do we only study the DC gain in VLC channel modeling? In all the papers and ...
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My speaker connected to my TV is making weird noises only when playing videos [closed]

Apologies if this is the incorrect forum, if anyone knows of a better forum to ask on I would appreciate the redirection. I have a very specific issue regarding audio playback from my TV. I have a ...
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Optical filters: What is the difference between Free Spectral Range (FSR) and the resolution based on (FWHM)

I have a question regarding the Free Spectral Range (FSR) and resolution based on (FWHM) of optical filters like based on Fabry-Perot-Interferometers. As of now, I always thought of the resolution as ...
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How do DVD players know how fast to spin?

Not sure if this is the right place to ask this, but here it goes: Different optical discs have different rotational speeds, based on the size of the pits and the bitrate. Newer disks have smaller ...
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Link budget: receive power > 0

I want to compute link budget in free space laser communication. My input parameters: wave length 700 nm, transmitter aperture: 0,88/0,15/0,2 m, receiver aperture: 0,3/0,5/1 My results: I have a ...
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USB-C to TOSLINK homemade (almost-) passive cord?

I'm trying to connect my phone to my portable DAC which has an optical in. I am looking for a solid 24-bit (up to 32-bit) cable for signal transmission, pre-processing. I've researched TOSLINK TX ...
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4 answers
106 views

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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What happens when we reach the maximun atenuation in Optical Networks Terminals (Optical fiber )?

Let´s suppose We have the following Optical Network Terminal : According to datasheet, the receiver sensitivity is : -27 dBm Now Let´s suppose We have the following fiber optical network : As we ...
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Maximum Achievable distance, given the maximum delay, in optical fiber (single mode) and ethernet?

I have the following problem to solve. I have to find the maximum achievable distance between two nodes of a network, given the maximum delay possible between them. The connection can be single mode ...
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133 views

Low cost position detection using a diy "encoder" [closed]

I'm building a machine that is adjustable, so there is this mechanical arm that can be in 5 different positions. I was thinking on building a custom encoder, I can easily make holes in each position ...
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Measurement of output current of a photodiode

I am a German student. My task is to conduct a characterization of a photodiode (KPEIMC-UDCOM by Kyosemi.) The photodiode will be illuminated by 850-1550 nm laser diodes. It would be good (but not ...
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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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3 votes
4 answers
108 views

Optical detection of a fan wheel

I want to detect the rotation speed of an impeller (fan wheel). Imagine a fan without a motor submerged in a liquid. This device is used for visual indication of liquid flow. I want to detect the ...
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1 answer
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What are the limits to parallel shift registers in electronics (in comparison to optics)?

Brackenbury and Mason in 1988 (https://iopscience.iop.org/article/10.1088/0022-3727/21/10S/044) said, on comparing parallel shift registers in electronic and optical computing, 'When implementing such ...
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Photon lifetime in an optical cavity

Hi I have the following problem and data for an optical cavity. Length \$ L=100 \mu m\$ Reflectivity \$R=0.33\$ Refraction index \$n=3.6\$ Inner losses \$p_i=20 cm^{-1}\$ Now I have to determine the ...
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ADNS-5050 components needed

I'm planning a project involving the ADNS-5050 optical mouse sensor package. The data sheet for this package says that it needs to be combined with 4 capacitors, and it has a diagramme that I think is ...
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Approaches to creating better mouse pointing hardware for absolute input?

I play the video game osu!. Osu! is a game that requires the player to quickly move the mouse pointer to different areas of the screen in a precise manner. A game such as osu! lays out unique ...
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2 votes
2 answers
298 views

Using QSFP28 Module at Lower Lane Rate

I have an application that requires optical transmission of 4x16 Gbps SERDES lanes over fiber. A QSFP28 module for 100G ethernet seems like a great commercial solution--it can take the four lanes and ...
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How best to connect two optical limit switches to share one I/O pin

I'm trying to build a CNC laser engraver using a scrap industrial CNC gantry as a donor. The system already has optical limit switches for the max & min on each axis. I can't use the current ...
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Q-value in APD photodetector

I try to calculate the Q value of APD photodetector with these parameters: $$R \hspace{0.1in} (response) = 1$$ $$M \hspace{0.1in} (magnification) = 10$$ $$k \hspace{0.1in} (ionization \hspace{0.1in} ...
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2 answers
86 views

Selection of wavelength for optical reflective sensing

Most of the reflective sensors in the market use either red or near IR wavelength and have a very short range (in the range of mm). Given the reflectance of the Si at different wavelengths and ...
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1 vote
4 answers
242 views

Precision Current Sink for LED Modulation

I one of my first designs, I am attempting to simulate a high precision optical transmitter using an LED by varying the brightness in linearly with the incoming signal. The input signal is BFSK, ...
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1 answer
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Optical displacement sensor noise and current to voltage conversion

I'm currently involved in a project with the aim of measuring the tremor of mice limbs (displacements of about 100 um). The sensor my group has chosen is TCRT5000 (Vishay), but we are facing several ...
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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 ...
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Detecting movement of a mechanical ring using optical sensors

I need help deciding on which sensor to use for my current home project. Basically I'm trying to replicate the Numio Control but at much cheaper cost. If it is successful I will publish the result ...
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How does one match irradiance to Luminous Intensity in Candela of source?

A light source has an Irradiance of about 1.6 W/m²/nm at wavelenght 385nm and an LED: Peak Wavelength 385nm Viewing Angle 30 ° Luminous Intensity 80 mcd If this light source shines on a ...
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Optical Isolation of BNC trigger?

I am wondering if there is a more practical way to provide optical isolation for a BNC trigger. I am currently using the following: https://www.eagleharbortech.com/product-categories/fiber-optic-...
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How to Work with a Optical Fiber Ribbon

I got a piece of fiber optical cable that is in the form of a "ribbon cable" (see pictures). I have seen tools and procedures for making connections on a single strand of optical fiber. I would like ...
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3 votes
2 answers
225 views

Anyone got these optical encoders working? [closed]

I got these Optical Encoders from a local vendor and connected it to my arduino in the following order; (+)----> 5v (-)---> Gnd (01)--->2 (02)--->3 But, it burnt and smoked out as soon as I ...
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3 votes
1 answer
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SMD LED: How to calculate optical power (in mW) from luminous intensity (in mcd)?

I chose an LED for my application but I need optical power, in mW. In the data sheet, luminous intensity is shown in mcd but I did not find formulas for calculation although there are graphs, etc. ...
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2 votes
2 answers
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I've seen many conflicting answers online: For optical storage, does a pit represent a '1' bit or does a land represent a '1' bit?

I've seen many conflicting answers online so: When reading an optical disk, which one of these is true: A 'pit' represents 1 and a 'land' represents 0 or A 'pit' represents 0 and a 'land' ...
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Water level measurement using Optical Mouse Sensor

I wonder if anyone has hacked an Optical Mouse sensor to measure water level in an overhead water tank? Its possible to read frames data from the sensor and if those frames could be processed with a ...
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3 answers
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Opto switch for detecting translucent polypropylene

I am building a liquid handler (a CNC machine that pipettes small quantities of liquids). The machine switches polypropylene "tips" between pipetting different fluids. Positional accuracy within 0.5mm ...
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How come optical data modulation is faster than that of electrical modulation while optical modulation is done by electricity?

why optical data is of high bandwidth that that of electrical copper data bandwidth when we use electrical signal to achieve optical data modulation ?
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2 answers
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How does an optical (toslink) to HDMI cable/converter work?

I'm looking at the small Sonos optical audio (toslink) -> HDMI cable in front of me and I don't know how it works (https://www.sonos.com/en/shop/optical-audio-adaptor.html). It has an optical audio ...
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visible light communication data reception

My project is on visible light communication. I use a 555 timer circuit to modulate data with 200 KHz signal using a 3 watt LED. At the receiver I use a photodiode (PS100-6-CER2PIN First Sensor ...
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2 votes
2 answers
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Using SFP modules from a microcontroller

I'm interested in having an embedded device send data optically. This is for test and measurement, where having conductive cables is problematic since it will perturb the measurement. The device is ...
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what is the performance of an OFDM system in one-path channel (Flat response channel),with no multi path propagation?

i work on modelling a OFDM system in a indoor optical wireless channel (LOS channel), since my channel is LOS there is no multi -path propagation , so the delay spread of my channel is much smaller ...
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632 views

How to increase (optical) power of arduino circuit with LED? Increasing current with fixed voltage

We have an LED that when connected to an Arduino board provides an optical power of 22.58 mW. The circuit is just the LED in the digital Pin with the Arduino powered by the computer using a USB cable. ...
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3 answers
2k views

Circuit design using 2-stage opamp

I am making a medical device that requires to sense very very low intensity blue light. I have attached my circuit design which is a 2-stage amplifier(transimpedance and differential amplifier), but ...
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How to test an optical sensor board from printer

I have salvaged an optical sensor board from a HP printer just as the one shown c9101-80190-A to use it other hobby projects. The problem is, I cannot be sure whether it's working or not, as I get ...
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197 views

Can OID technology return an X, Y coordinate?

We are working with a overseas vendor that is using SONIX OID technology. (according to our vendor we are using OID v2) We are using OID technology from them. A smartpen with OID technology is able ...
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