Questions tagged [rgb]

Short for: Red Green Blue. The primary colors in light. Mix them to create any imaginable visible color of light. Questions are typical in reference to RGB Leds, RGB Led drivers, and code related to mixing RGB light, but can include RGB Video Standard in VGA monitors.

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Why can't RGB or bicolour LEDs produce a decent yellow?

I have several different RGB LEDs and bicolour red/green LEDs, from different suppliers. I find that, with the appropriate resistors, they can produce a perfect orange and cyan; and a barely ...
29
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4answers
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Why are the three component LEDs in an RGB LED so unbalanced?

I was recently spec-ing some RGB LEDs for a project, when I noticed that the millicandela ratings on the three colors are rarely close to the same number. (i.e. 710mcd Red, 1250mcd Green, 240mcd Blue)....
19
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1answer
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What makes a good RGB LED

I am looking for supplier for RGB LEDs for an upcoming project RGB POV LED Globe. Normally I would go to my local electronics supply story, but this project requires lots (~1000) of LEDs and my local ...
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2answers
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Controlling an RGB LED color range from an analog temperature sensor (no Arduino, etc.)

I'd like to combine an analog temperature sensor with an RGB LED so that I get a range of colors based on temperature. Low temperature blue, high temperature red, with color fade between them as the ...
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Why do some RGB LEDs have six legs?

Others have four legs, which makes sense to me, as ground can be shared. One of many examples of a six legged RGB LED is the Kingbright KAF-5060PBESEEVGC.
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Red Green Blue LED

Do you need to use different resistors against each of the colours on an RGB LED?
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2answers
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Hooking up multiple RGB LEDs while using a minimal number of PWM pins on an Arduino?

I currently have an anode RGB connected to the 11, 10, & 9 PWM pins on my arduino. However I would like to add 3 more LED's to my project, but I don't want to necessarily take up every single PWM ...
9
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1answer
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Why does a resistor in my Neopixel data line work at all?

Adafruit's best practices for their Neopixel LED strings say, "Place a 300 to 500 Ohm resistor between the Arduino data output pin and the input to the first NeoPixel." Someone asked about the ...
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5answers
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Is there a single IC that can control a 8x8 RGB LED Matrix

I was wondering if there was a single IC like the MAX6960 that could control a whole 8x8 RGB LED Matrix because the MAX6960 can only control a RGY.
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POV globe speed questions

I am planning on creating a RGB LED POV globe only physically larger then that one. I am planning on using 64 RGB LEDs, requiring 3x pins per LED for a total of 192 outputs. Obviously I am going to ...
6
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1answer
2k views

Digital RGB interface EMI filtering

Consider the following system: where: The motherboard contains a LCD controller (SSD1963 from Solomon Systech) and other components (application processor, solenoid drivers, power supplies, etc.) ...
6
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1answer
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RGB LED - Set intensity on Red and Blue

I've recently purchased SparkFun's starter arduino kit, which comes with a 4-legged RGB LED. If I understand correctly, this RGB LED should be able to access the full range of RGB colors, with 255 ...
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What resistor to use with this RGB LED?

i have this led, and im not sure what resistor to use to drop the 5v current to an appropriate voltage and produce the appropriate current. the LED is rated at 200mA, but the data sheet says i ...
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2answers
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Small, cheap, and simple driver for 16 RGB LEDs

I am working on a board design that will put 16 RGB LEDs in a circle around a rotary encoder. I want this setup to be simple so that I can run it from any micro with limited software (ie. built in PWM ...
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4answers
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Can I replace these many capacitors with just one?

I'm designing a schematic for an addressable RGB LEDs array and I've chosen the WS2812B because of how common and cheap they are. Looking at the typical application circuit, I noticed there is a ...
4
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3answers
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Why must resistors be on the respective anode terminals instead of the common cathode terminal of a RGB LED?

Different from the best answer of this one: Why does a resistor need to be on the anode of an LED? But well, I'm also an electronics noob ^.^ Recently I bought the official Arduino starter kit and ...
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2answers
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How much does an op-amp delay?

I will be using the OPA694 for some video processing. I would like to know how much delay it introduces, so I can account for it. Here are some specifications of the op-amp: ...
4
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1answer
388 views

RGB and SRGB difference and their use

I am working on a project which include displaying RGB colors. I would like to know what is the difference between RGB and SRGB. Is it possible to have srgb colors in led. As SRGB has been used for ...
4
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2answers
817 views

Powering RGB LED's and using a PWM chip; series or parallel?

I'm working on a hobby project where I will be using an Arduino board and a TLC 5940 to control 5 different groups of RGB LED's. The number of LED's in any particular group will not necessarily match ...
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2answers
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How can I stop the flicker of LEDs?

Recently I started messing around with controlling RGB leds with the Arduino for a project I'm building, so I built the following schematic: simulate this circuit – Schematic created using ...
4
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4answers
347 views

Driving 10W RGB LED Red Channel Issue

Been a while since I have been on here but I do not know where else to turn for help! This is more of a hardware issue than anything so i do hope that I am in the correct forums to be asking, if ...
4
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1answer
1k views

Driving three high power RGB LEDs with PWM, from a 9v battery

I'm building some LED juggling balls. I'm planning to power an Arduino with two AA batteries, and power the LEDs with a 9V battery. I want to drive three of these 3W RGB LEDS in parallel, with PWM. I'...
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2answers
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Fading RGB led with ATtiny2313 timer

I'm trying to make mood lamp with only hardware PWM and interrupts (i. e. main loop should be empty). I'm doing it as a challenge to learn how timers work, not for any practical reason. So far I've ...
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1answer
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RGBHV (VGA) to YPbPr Converter and Waveforms?

Purely for hobby, I am working on an RGBHV (VGA) to YPbPr (Component) converter circuit for old games consoles modified to output RGBHV on a VGA cable. From the game consoles, the RGB signal is taken ...
3
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4answers
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Voltage regulator too hot to touch [duplicate]

I'm working on an RGB LED project. I'm using this as the power supply: https://www.sparkfun.com/products/114 It uses an LM317 which according to the data sheet can supply up to 1.5A. The LED's I'm ...
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3answers
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Change RGB leds intensity?

Sorry if this is too basic but I don't understand this issue. Right now, using an MCU, I change the RGB colours of an LED strip with 3 PWM signals. All colours works great . The thing is, when I am ...
3
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4answers
382 views

Painting Rainbows

I was painting my 2 year old's daughter's bedroom yesterday, she handed me a paint brush and asked me to paint her a rainbow. I could paint her a rainbow, using paint, but I don't have many colour ...
3
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3answers
855 views

RGB & Proximity Sensor at about 6 feet

New to this site so hoping it's the right place to ask. I'm trying to prototype something for use in a retail store and an idea a teammate had was using an RGB sensor to detect both ambient color as ...
3
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2answers
267 views

Powering 30m of RGB LED strips?

I'm currently interested in following this tutorial which explains how to create a homebridge (ESP8266) controlled 12v RGB strip which is exactly what I've been looking for. However, whilst I do ...
3
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2answers
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How do I calculate what resistors I need for RGB LEDs with 3.7V? [duplicate]

I have a total of 4 x RGB LEDs. I am hoping to power these as well as a RFduino BLE module with a 3.7V lithium rechargeable battery. I was just wondering how I would go about calculating the ...
3
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2answers
2k views

The Transistor Menace - Questions regarding an Arduino rgb LED project

I've been browsing this forum and the internet now for a couple of days and what I thought would be an easy side project turned into a (for me) quite complicated matter. I'm planning to build a mood ...
3
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1answer
222 views

Colour correcting RGB LEDs - possibly with science

I have some RGB LEDs (eBay - no datasheet, 4 pin, common cathode, 5mm). I am colourblind. I'd like to create a palette of colours which appear distinctly for most people's eyes, perhaps 16 colours or ...
3
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2answers
226 views

TLC5940 - with 200LEDs from car battery

I'm working on project that involves 100 white and 100 RGB leds, controlled with 25 TLC5940. I've managed to connect three TLCs to Arduino MEGAv3 and so far so good. I've found out that I have to ...
3
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1answer
1k views

how to measure RBG values of a color using phototransistor

I am developing a circuit which can measure RGB values of a given color. I have used LED to transmit light and reflected light is filtered by 3 R, G, B filter papers. Earlier I used LDR and found that ...
3
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1answer
186 views

RGB led driver maximum current

I am planning to build a device that includes an high power RGB LED (either a lightsaber or a decorative object for the girlfriend - I still have to decide), where high power means about 3x3W. I've ...
3
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2answers
249 views

hack color changing candle circuit

I'd like to modify a color changing candle (example) circuit so it can be turned on without lighting the actual candle. It uses a photodiode and a optical fiber alongside the wick to cycle the RGB ...
3
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1answer
5k views

Long term reliability of addressable RGB LED strips? How do WS2812B, APA102, and SK6812 compare? [closed]

I'm about to order a lot of RGB LED strips for a project that will hopefully be running for years if not decades. I used to have very good luck with strips using the WS2812B chips, but in recent ...
3
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1answer
6k views

how to convert a Sync-on-green to VGA (seperate sync) signal?

I have a computer (VAXstation 3100/M76), that has a sync-on-green output: red --( green + sync --( blue --( I want to attach that to a standard ...
3
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1answer
4k views

Read and decode .led file

I'm working on a flexible LED screen persisting of 20 meters of digital RGB LED strip with WS2811 IC for each LED. I want to control this using Arduino, which isn't a problem using FastSPI. My ...
2
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4answers
236 views

Single transistor instead of RGB screen

In today's screens, each individual pixel is created by the combination of three transistor as Red Green Blue. But, colours are already just different frequency waves. Why aren't pixels made by just ...
2
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2answers
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RGB LED brightness levels

Do RGB LEDs have very different brightness levels? I'm running an RGB LED (common cathode) via some TIP120 transistors, controlled from a raspberry Pi. There is a 5v feed from the rPi. Initially I ...
2
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2answers
3k views

how to get the RGB value of a color using phototransistor or photodiode?

I'm making a color analyzer which can measure Red, Green, and Blue portions of a color (ex: 128,255,0).I'm not supposed to use pre-made color sensors and need 1% ACCURACY. I used three LEDs - R,B &...
2
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2answers
5k views

How does a PC detect a VGA monitor?

Currently I am trying to connect my LCD to my laptop through a VGA connector. The LCD has 6 wires out of it which I am trying to solder to a VGA male connector, But the laptop doesn't detect the LCD. ...
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2answers
7k views

LDR + RGB Led = Color sensor. How to calibrate it?

1$ color sensor. My adventures in electronics continue. While talking with a friend about colors, he told me about color sensors. Later I remembered the video where they sort smarties and so I ...
2
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2answers
13k views

Can I use a 25 meter LED stripe with a single power adapter?

I have 5 stripes of 5m length and 300 RGB LEDs (type 5050) each. One LED consumes about 20 mA at 12 V. Therefore, my whole 25m setup would use about 30 A. Is it safe to connect the 5 stripes series ...
2
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2answers
2k views

RGB LED flickering with PWM

I just have issues with the RGB LED flickering under low duty-cycle like 10% on time with 780 Hz. I tried changing the PWM frequency to lower and higher rate but I still see flickering at low duty-...
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2answers
2k views

ATtiny25 PWM LED driver with brightness control

I'll be building a piece of RGB LED jewelry for a gift. It's basically a pair of earphones with one or two RGB LEDs on each, with a small ATtiny25-based PWM driver in a small enclosure. I'll probably ...
2
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1answer
144 views

Why is my RGB LED strip passing current through the transistor?

I am following this schematic: http://www.electronoobs.com/eng_arduino_tut13_sch2.php It uses a BD140 PNP transistor. I checked the wiring was correct. Basically, the transistor boosts the current ...
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2answers
92 views

Could You Use Common cathode RGB LED without providing power to G and B

I know this kind of defeats the purpose of an (common cathode) RGB LED, but if you only wanted Red on a RGB LED would it be acceptable to use only the R pin and the Cathode pin to get just red? Sorry ...
2
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2answers
301 views

LED hub purpose?

What is the main purpose of LED hub, is it used only for RGB matrices to connect shift registers for every color or there are some other applications? I'm working with HUB75 and that is the reason ...