Light is a tag about anything generates photons in the visible spectrum

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15 views

Relationship between light intensity, angle of incidence, resistance of LDR

I want to find the mathematical relationship between the resistance of an LDR, its area, light intensity, angle of incidence of sunlight. It would be great if someone can direct me to a place where I ...
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2answers
38 views

How to find the value on a chart scaled in decibels

I have the following chart The blue line is the one I am interested in. The question is how can I determine the value in LUX if I have the output voltage? The problem is that I don't have any ...
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1answer
51 views

How would you go about creating a lux meter for very low light (0.0001 to 1 lux)?

I like to take pictures of the the sky in really dark places like Death Valley. To get an estimate of exposure times for the foreground I would like to measure the light intensity. According to ...
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0answers
118 views

How do filament LED bulbs work, looking very similar to incandescent bulbs?

Filament LED bulbs use very narrow strips containing the LED, which look similar to filaments of an old incandescent bulb. Here's a good picture: http://www.aruana-led.de/ They look like a normal ...
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0answers
14 views

CFL and CCFL difference: Can I use CFL balast like CCFL inverter?

I want to ask where is the difference in CFL (compact fluorescent lamp) and CCFL (cold cathode fluorescent light) in the meaning of thier elctrical circuit. I know it's two different types of ...
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1answer
79 views

Which diodes for 12v indicator light circuit?

Which diodes for 12v indicator light circuit? I have a car whose signal light audio indicator is too soft to hear. I would like to set-up an visual indicator on the dash for when the signal lights ...
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1answer
34 views

Detecting and identifying different light sources in arduino?

I want to detect different light sources in arduino. The first Idea about solving this problem came into my mind was to add three light detection sensors (LDR, IR receiver Diode and Photo transistor) ...
4
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1answer
87 views

Which photo sensor should I use in dust prone areas?

I am trying to automate the street lights near my house by using a photo sensor. But before even starting I thought of asking if there is any way of sensing light in dust prone areas, since I don't ...
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1answer
83 views

Photodiode Array Wiring

Sorry if this is a basic question. I would like to use photodiodes to precisely measure changes to light amplitude using an Arduino, similar to Figure 2 here: However, I would like to wire six ...
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4answers
81 views

Light sensor to sense light level

I have an application where I am trying to monitor a defect in a web based manufacturing process. This defect can be seen if one side of the substrate is lighted and the transmitted light is viewed ...
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4answers
213 views

Highly accurate constant current source

I want a continuous and highly stable light from an LED for around a couple of hours, for which I need a highly constant and highly stable current source. I prefer an opamp-based circuit for the same. ...
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1answer
65 views

How do external circuits in light switching units (such as Lightwave RF) use the mains wiring for power?

LightwaveRF is a simple switching unit that contains additional circuitry to enable automatic wireless switching. The additional circuit is powered by the mains light switching circuit. This is my ...
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1answer
159 views

Low-level light detection

I'm looking for the best way to detect a weak bluish light (440nm) in a dark environment - with "best" I mean with highest sensitivity possible. I've noticed that most LDRs and photodiodes have their ...
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3answers
90 views

Low Voltage DC controlling 120 AC, with Arduino

I'm looking for a type of device I can hook my arduino (micro-controller) to that will control a set of lights that require 120VAC. Basically I will be making a light organ, where the arduino will be ...
3
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2answers
140 views

Why do some power transistors emit light?

I am specifically looking for an image I believe I have seen before so I can link it to a friend. It was a TO-3 packaged device with the metal cap removed, showing a power device emitting light as a ...
2
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1answer
64 views

Is a pin fin heatsink with 4 fans enough for 2x 80W LEDs

I need advice: I plan to use a heat-sink for cooling 2x 80W white LEDs over my friend's tank. The heat-sink is a "pin fin" design, 6 inches by 6 inches which combined with active cooling should ...
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1answer
52 views

Viability of an LED grid

I am a newbie with these type of applications, but I am trying to see if this idea would work out. Essentially what I am trying to do is build a large panel 2ft x 20ft that will act as one large ...
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2answers
154 views

Permanently dimming an incandescent light bulb

I have purchased a nice light bulb with long visible wires/resistors and plugged it in, on the ceiling. It burns too bright without a dimmer and does not look as intended (also the lifespan ...
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3answers
97 views

How to tell the lumen output of these LED's

I'm trying to build a light fixture for my aquarium, but I'm having difficulty understanding the various way manufacturers represent light output. I'm trying to compare the output of CREEXPE-ROY-3 ...
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1answer
46 views

What issues are there in designing a LED lighting system to replace Halogen G4 lighting

I wish to design a lighting system using electronics and LEDs as required to replace existing G4 Halogen lamps in order to increase available light levels in the available space. Situatiuon: Kitchen ...
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1answer
68 views

Looking for replacement LED [closed]

I'm looking for someone who can tell me what kind of LED this is (The barcode is: 5541475) It's the blue LED from this projector: Acer K135 I'm trying to modify the beamer and replace the LED with ...
3
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0answers
77 views

Preamplifier that responds to 10 kHz [closed]

I am having a problem of designing pre-amplifier that responds to light pulses of 10 kHz. I have designed the one below but I don't understand the scenario in which the output voltage builds up to a ...
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0answers
70 views

GPIO and light interrupter

I have a GPIO board on hand like this: I am a beginner to GPIO board and wish to seek some suggestions. I would like to connect a light interrupter / photointerrupter to one of the four inputs, but ...
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0answers
206 views

MOC3010 & BT136 with Arduino as trigger to power AC light

I've spend days debugging this circuit and have exhausted all possible solutions. I'm trying to use an Arduino PWM pin to light a 120V AC lightbulb. In order to do this I'm using a MOC3010 ...
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2answers
104 views

Convert Plugin Christmas decoration to a battery operated light

I have an old ceramic Christmas tree that I would like to convert to a battery powered source in order to get rid of the cord. Ideally I'd love to add a timer to it as well. I'm not sure what ...
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1answer
87 views

Have Pins light up after pushing a button/switch

I'm trying to create a "Push Pin" map for a friend as a gift. My friend has traveled through out the world and I'd like to organize the pins by year. So a different color pin for each year he has ...
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3answers
123 views

How to receive faint AM light

I am going to be amplitude modulating a high power LED light from a peak on a mountain. I want to recieve this faint light as far as physically possible before the light fades out too much to recieve. ...
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1answer
111 views

Improvized small aquarium lighting

I have a small aquarium that has been illuminated so far by a 15W fluorescent lamp. The problem is that the ballast has broken (melted) after 2 years of use, and the only replacements I could find on ...
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2answers
369 views

Can I shorten a length of C9 Christmas lights? [closed]

I have a string of 25 C9 LED Christmas lights, and I'd like to shorten the string. After untangling the string, they seem to be wired like this... simulate this circuit – Schematic ...
2
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2answers
184 views

Microcontroller Protection

I used microcontroller for wireless application. Problems arise when I put the microcontroller in high rainfall areas. The microcontroller is often damaged by lightning. How to protect data lines ...
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1answer
169 views

Using Arduino Uno R3 + Ethernet Module, how to control current pass to Lamps?

I have Arduino Uno R3 and Arduino Ethernet Shield V5. What's missing in order to control 6+ lights (bulbs) from my home? Those are connected to 220V AC. My idea is to send a packet via ethernet that ...
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2answers
206 views

Illuminate keyboard using Scroll Lock key

I have a keyboard that I'd like to illuminate when pressing the Scroll Lock key, but I'm not really good when it comes to designing something like that. I'm planning to use a transistor that will ...
0
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1answer
116 views

Waterproof power connections

I need light up about 960 square feet of translucent flooring from below. It's an outdoor installation, so it needs to be waterproof. Further, it has to be done in a matter of just a few weeks, and, ...
14
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1answer
626 views

How does a fire detector distinguishes between smoke particles and others?

Many fire detectors are optic so that when smoke comes in the fire detector, it causes the light from LED reflect to the photodiode. But the question is why don't they alarm when somebody takes a ...
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1answer
716 views

How is digital information encoded/decoded in light or radio waves?

I know exactly how DAC and ADC works; that's not my concern. What I am asking is how the constituent state of matter (and the "states" represented by them) in a circuit can be transferred to a set of ...
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1answer
122 views

Why do fluorescent bulbs hum/buzz? [closed]

Why do fluorescent lamps buzz/hum? I have one above my desk right now and it is constantly humming/buzzing. Does the bulb need to be replaced? Do I have to take the light fixture apart and replace ...
0
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1answer
85 views

Proximity Sensor [closed]

I am trying to make a circuit that as an object moves closer to a proximity sensor it triggers a dimmer switch controlling a light and amplifier for loudspeakers. Basically as an object moves closer ...
2
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3answers
189 views

PWM duty cycle vs candelas for LEDs

What is the functional relation between PWM duty cycle for LED and its luminous intensity (candelas)? Linear or not?
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1answer
202 views

How can I trigger a photography strobe from a iPhone LED flash?

I would like to trigger a photography/studio strobe flash based on the flash of an iPhone camera's LED flash. I'm picturing a device that I could attach to the back of the iPhone temporarily when I ...
3
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1answer
161 views

Will a incandescent burn out if you leave them on forever?

We've all had a time or too two that when you really needed light, and I mean need it immediately, and you flip on the switch, and with a pop and a bright flash, your incandescent is toast. However, I ...
2
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2answers
128 views

Alkaline cells vs. LED flashlight

I have (had, actually) an El Cheapo pocket LED flashlight powered by 3 AAA cells. It was shipped with very low quality "salt" cells (regular, low weight - someone please suggest a proper English name ...
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0answers
74 views

LED Lighting Forward Voltage Constant Current

I have a qty of 6 7W led luminaires that would normally use individual 350mA drivers. I am looking to use one driver to supply all 6. However, I understand that the forward voltage of 20V per ...
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1answer
256 views

How to power “arduino” from wall?

So I have a fake "arduino" that I put together (The main components on a breadboard, i.e. ATmega328, capacitors, ocilator, etc) and I am trying to use it to overide a light switch (When the light ...
3
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1answer
104 views

Creating an LED array light box

I'm wanting to make a light box of sorts from LEDs and wanted to run it by you to confirm I have the right idea... I have ordered 500 super bright LEDs off eBay and want to wire loads of them ...
2
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2answers
504 views

Energy-efficient LED driver circuit

I want to light a normal LED for as long as possible on two AA or AAA batteries. It does not have to blink or so, just stay on. The LED doesn't have to light at the max, as long as it's visible from ...
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2answers
424 views

How can I power the blue LEDs separetely on this aquarium light?

I have a Beamswork LED aquarium light like this. It has a 3 way switch: All LEDs off Blue LEDs on only White AND blue LEDs on It has a single mains power plug. What I want to do is make it have ...
2
votes
3answers
2k views

How much can I safely plug into a light socket converted to a standard outlet? [closed]

I just moved my office desk from our extra bedroom on to our stairway landing. The tricky thing was that there was no wall outlet to plug anything into. However, there was a nearby light socket, ...
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1answer
1k views

Light bulb exploded [closed]

This morning, one of the lights in my house began to flicker. I didn't think much of it, and left the room to get a drink. While I was in the other room, I heard a bang, and came back to find broken ...
3
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3answers
191 views

How to switch light on by standing on a mat

I'm working on a project for school. And I have this dance matt. As long as you stand on that matt the light should go on and stay on until you step off the matt again. But I have no idea how to make ...
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1answer
354 views

virtual light communication

I have to design a project that uses an LED to transmit data and a LDR to receive the data or signal from the LED. But the problem is I have to use two Arduino UNO boards, one for LED transmit and ...