Questions tagged [led-matrix]

Anything related to LED matrices. A LED matrix is a rectangular arrangement of LEDs where all LEDs in a row have their cathode (or anode) connected to the same line and all LEDs in a column have their anode (or cathode) connected to the same line. In this way a single LED can be lit supplying power to the lines corresponding to its row and column coordinates.

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Do I need a resistor to connect this LED lamp?

I purchased this LED lamp on Aliexpress, the spec says it's 36V, 20W. I want to know how to connect it to my ebike 36V battery, in particular can I connect it directly or I need a resistor? I tried ...
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Should I continue use daisy chaining or use another Chip Select PIN in MAX7219 8×8 LED matrix module to increase height dimension?

Consider I have 4 daised chaining of MX7219 LED Matrix 8×8. Thats mean i have more width than height (32×8) or (width×height) If i want improve overal width of LED again, thats mean i must continue ...
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LED matrix power and multiplexing

I am trying to build a 7 character LED matrix (so 5x7 x 7 LEDs). I need it to be controllable from an ESP32 with Arduino code. So far what I've learned is that I need shift registers in order to ...
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3 answers
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Multiplex grid of LEDs with microcontroller

I'm trying to multiplex a grid of LEDs directly from a microcontroller but all the schematics I'm seeing online show how to multiplex to some kind of IC chip or board that isn't the main processor. I ...
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2 votes
2 answers
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LED Matrix to reduce current consumption

I'm trying to control RGB LEDs via USB. All LEDs have the same color, so I'm controlling them with only 3 PWM signals (generated from a PIC). The problem I'm facing is to reduce the current needed in ...
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1 answer
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How to use GPIO on STM32 (F103VET6) as a kind of of output battery?

After I learnt how to blink LEDs on the board, I came up with the idea of making a LED matrix. The schematic is like this: But I could not figure out how to light it! Every LED can be lighted under 2....
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2 answers
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How many 2N2222 transistors required for 3x3 LED matrix to mutiplex

I have made a 3x3 LED matrix and was able to turn them on/off individually using an Arduino, but now I want to use an external 3 V instead of the Arduino pin voltage. How many 2N2222 transistors are ...
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1 answer
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Help me identify pin of this LED Matrix PCB

LED Matrix bicolors (Orange/Green) PCB board of 10 LED Matrix of 4 x 8 (LTP23548AA-NB) It looks like J3 is regular UART|USB. I'm trying to find what J1 and J2 are about. The goal is to add a ...
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2 answers
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APA102 LED strips behaving weirdly and flickering towards the end

I am trying to make a 29 x 29 LED matrix to display animations using the APA102 (Dotstar) LEDs with an Arduino MKR Vidor 4000 as a microcontroller. I have connected the data and clock signals of the ...
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Bigger Matrix with the IS31FL3731

Normally the IS31FL3731 makes a 16x9 matrix using two Charlieplexed arrays. I want to make a bigger square array, around 12x12 say. Is it possible to wire connect the IS31FL3731 in such a way that the ...
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Help regarding identification of a DC-DC ic bearing the print "ER=1B 73H" in a faulty BOE-hm185wx1-400 panel

I am having a faulty BOE-hm185wx1-400 panel, where the MLG voltage has dropped to 15 V instead of the usual 25.4 volts. After a bit of diagnosis, it appears that the DC-DC ic below is possibly faulty. ...
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I need to design 182 RGB LED array circuit

I looked for designs for PWM dimming RGB LED arrays on the internet, and I found this circuit with a current mirror: As the title says, I am designing an LED panel with 182 RGB LEDs. I think the ...
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ESP32 on custom PCB - not booting

I have been working on a project that uses an ESP32 board to drive a HUB75E RGB matrix (using the library from mrfaptastic ) . And as an extra challenge, I decided to try and design my own PCB for it. ...
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Clearance between SMD components

I'm designing a compact PCB. It consists of non-addressable 5050 RGB LEDs. I'm concerned about how close they are. I'm going to use the SMD assembly service provided by JLCPLB. Should I change the ...
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LED Array Controller Circuit PCB Design Questions and Feedback

Background I'm designing a LED controller based on a Teensy 4.1, some AD9833 Function Generators and some TLC5948 LED Drivers. I'm aiming to make an instrument of sorts, specifically a POV display ...
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1 answer
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How to calculate the resistor value necessary for the columns 8x8 led matrix?

I am building an 8x8 led matrix using 5mm LEDs (3.2V, 20mA). I connect it to the arduino UNO through the I2C using the GPIO expander MCP23017. The circuit is as follows: A matrix column is made up of ...
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Design LED light system, Lumen low

I want to design a 4-way lighting system using LEDs. This is what I have so far. LED driver: https://www.ledsupply.com/led-drivers/buckblock-dc-led-driver LED: https://www.ledsupply.com/leds/cree-...
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LED matrix and current sink basics

I'm trying to implement the circuit shown in the schematic below (not complete, just for reference,) where the idea is to turn on only one LED at a time -hence the ADG1406- with a frequency of about ...
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Independent LED control in a matrix

My task is to control 64 LEDs with a 16-output drive. The control of each LED must be individual, that is, the activation of one LED must not interfere in the functionality of another. I'm using an <...
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Power 100+ 5v LED matrices

I'm trying to power over 100 LED matrices laid out in a long, single chain similar to a stock ticker on news buildings. I do have the control part figured out but bringing power to the matrices is ...
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2 answers
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Powering hundreds of Adafruit's NeoPixels for a cosplay

My problem: I am trying to power a project with a 8x32px flexible matrix, 8x8px flexible matrix, 24px ring, 16px ring and 7px jewel (two of each), totalling up to a whopping 734 pixels. For my project ...
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Is the gauge big enough? String Pixel

I think I might need different pixels or an additional power supply. I bought 10 strings of 50 (12mm, 12v) pixels (aka WS2811 12mm 12V LED) to do my first matrix project. It says that is uses 22awg ...
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How a rgb led panel ( 16x32) works?

I'm currently working on a rgb led panel ( 16x32 1/4 scan rate ) ( driving with stm32f0) But i couldnt really understand what do i need to do to light up a specific led. When i apply one clock to R1 ...
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3 votes
1 answer
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Wattage of LED based growth light not consistent with LED usage

I have ordered a growth light for my plants. Only later did I realize that it said its a 2kW light, which seemed quite excessive as it is only the size of a small keyboard and not that densely ...
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1 vote
1 answer
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Is my circuit to power 38 kHz LED matrix correct?

I'd like to send 38kHz signals to an LED matrix to pulse 5V IR LEDs. The intention is that a lot of IR will be reflected when a finger is placed on a translucent 3mm acrylic panel above the LEDs. The ...
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2 votes
1 answer
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Can a Multiplexer be used as a Demultiplexer

I'm trying to build a musical machine for myself. I've come to a situation where I want to control 8 LEDs using 3 selector pins on my 74151 IC. I've attached the circuit diagram below. Looks like I'll ...
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2 answers
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Building an RGB LED Transilluminator?

I am attempting to build a gel transilluminator using RGB LEDs instead of UV fluorescent bulbs. Blue/Green LEDs can excite many fluorescent dyes similarly to UV without the harmful effects of UV. I ...
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1 answer
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Incorrect wiring for a DIY LED matrix?

I'm trying to get a home made LED matrix to show a rainbow pattern coming from the bottom up but it's playing this bizarre, dancing pattern. The matrix is in series, with 4X WS2811 addressable LED ...
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LED panel refresh rate and scan rate (multiplexing) relationship

Considering high-end panel as ROE Ruby 2.3 https://www.roevisual.nl/uploads/bestanden/ruby-r2.3-brochure-lr-v12020.pdf the scan rate (multiplexing) is \$s=1/12\$ and refresh rate is \$f=1920\$ Hz. ...
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2 answers
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Splitting power to two devices (Raspberry Pi & LED Matrix)

I am working on a small project involving a Raspberry Pi and an LED matrix. Both devices are rated for 5V but requiring different current (approximately 2A for the Pi and 4A for the LED matrix). ...
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Unexpected behavior setting non-default I2C address for HT16K33 LED Driver

The HT16K33 is an I2C controlled LED driver. The data sheet shows a standard way of setting the I2C slave address: I have implemented this circuit, but it does not work as expected. For the default ...
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Increasing LED brightness on arduino-controlled 8x10 LED matrix

I have made an 8x10 LED matrix, controlled using a CD4017 decade counter and Arduino. A simplified schematic is shown below: In the real version, there are 8 Arduino pins, and all 10 outputs of the ...
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1 answer
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LED panel wiring

I have matched an led driver (constant current power supply) to a circuit of leds such that no resistors are needed to limit the current by taking advantage of the leds "near" linear voltage ...
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3 votes
1 answer
198 views

Are IR LEDs placed under the same category as lasers?

I am creating a device which uses IR LEDs to illuminate the human eye, while an IR camera records the pupil dilation. From my research, I see that there are two standards which are related to the ...
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2 votes
2 answers
144 views

How to fix common error causing multiplexed LED segments to flash and dim

I bought an electrical engineering book and was surprised to see the following figure showing how to use a microcontroller to multiplex 4 LEDs using only 4 pins: This seemed right, logically, but ...
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1 answer
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Want to understand the led series/parallel and parallel/Series combination circuit

I'm Working on LED load design circuit which is up-to 64V@1.2A. I thought of giving LED's in series and parallel combination with switches to control the voltage but while searching I found one ...
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3 answers
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Two types of LEDs, serial - parallel combination

I am trying to design small DIY grow light for Chilli Peppers. I found ideal to use a combination of Samsung LM301H(https://www.samsung.com/led/lighting/mid-power-leds/3030-leds/lm301h/) and LM351H V2 ...
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3 answers
234 views

Help in choosing correct power supply for LED matrix

I'm quite new to electricity and electric components. I'm building an LED matrix from scratch on a small PCB. I will be using an IC for multiplexing, Transistor for controlling external power supply ...
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2 answers
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Why do LED/OLED HD and UHD displays have "global refresh rates"?

What is the benefit to scanning vs. individually addressing and updating lines or pixels or screen areas? Is there a standard interface to the majority of HD or UHD displays that allows the ...
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1 answer
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Use a decoder or direct address?

I am designing a RGB LED matrix of 1:4 scan 16x32 pixels As it is 1:4 I have 2 options Option A: Use A,B,C,D pins direct address to control the display or Option B: Use A,B pins only and use a ...
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1 answer
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Please recommend the tool set that fits the project [closed]

I'm looking at a few tools to make Surface Mounted Device RGB LED on a PCB. I used a heat gun yesterday for the first time. A video shows another method using a heated pad. And then yet another, more ...
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1 vote
1 answer
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How to sink more current than specified?

I am using the TLC5940 (datasheet) in an upcoming project to control the cathode side of an LED matrix, but each of my LEDs needs ...
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3 votes
0 answers
475 views

How to use MAX7219 with high current LEDs

I am fairly new to electronics. I am using the MAX7219 to control an led matrix and the data sheet for the MAX7219 says that the maximum current each light can get is 40mA, but for my purpose I need ...
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3 votes
7 answers
2k views

P channel MOSFET switching problem

I was trying to build a 16x9 LED matrix with an MCU with a limited amount of pins. The Anodes of the LEDs are driven by P-channel MOSFETs which gates are driven by a 74HC595 8 bit shift register. the ...
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1 vote
1 answer
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LED matrix on keyboard

I want to build a keyboard from scratch which will be illuminated as well (one LED per key/switch). Due to the fact that I don't need some fancy stuff, just turn the LEDs on/off, can I connect entire ...
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0 answers
429 views

Esp32 (Arduino Core) And Led Control Library issue

I am using esp32 devkit v1. My project is to make music reactive leds, the sound input of which is given through the "dabble" app on my smartphone plus turning leds on based on set distance from my ...
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2 answers
92 views

Trouble understanding Charlieplexing problem

I am trying to make a circuit that uses 3 pins to drive 6 LEDs using charlieplexing. The cicuit im using is this: What I don't understand though, is that when I want to turn D1 on, PB0=1, PB1=0, and ...
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1 answer
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LEDs are not glowing with same intensity in LED matrix

In my 16*8 LED matrix, I am switching the rows, so duty cycle is 100/8 = 12.5 %. Now, when the row contains fewer LEDs to be lit, they all glow brightly, but when more LEDs are turned on, they are all ...
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How do I control the latch signal for the TLC5958 LED driver?

I would like to drive 512 RGB LEDs with individually controllable brightness. My plan is to 8-way multiplex them so I would like to use an LED driver that is designed for multiplexing LED displays. I ...
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1 answer
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Identification of power connector for LED panels

We bought a bunch of 32x32 (6mm LED pitch) LED panels from a Shenzen company and some of the power cables were missing, so I'm currently trying to identify them. Attached are some images. We think it ...
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