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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66 views

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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74 views

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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35 views

Single pulse generator using discrete components

I've a board like this: simulate this circuit – Schematic created using CircuitLab What I want to do is to drive LEDs with OUTPUT pin. This LEDs are used like flash source, so I turn them ON ...
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16 views

ADG1408+TLC5940 LED matrix leakage

I am controlling a multiplexed LED matrix with a combination of an ADG1408 as power switch and a TLC5940 as current sink. The system works almost perfectly except for some LEDs that do not stay OFF ...
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44 views

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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48 views

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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39 views

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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69 views

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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68 views

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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40 views

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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2answers
119 views

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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141 views

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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1answer
54 views

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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1answer
77 views

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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29 views

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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283 views

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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57 views

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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1answer
55 views

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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81 views

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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72 views

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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1answer
108 views

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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49 views

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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58 views

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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1answer
119 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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161 views

Is my Wiring OK? - WS2811 LED Strips

I am looking to install WS2811 LED Strips inside coving on walls for a down lighting effect. I have drawn up a wiring plan but i am not sure if it is correct / the best way to do it. Is there any ...
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80 views

Suggestions to build high-power RGB LED matrix display

I'm building an 8x32 matrix display but it has to be high power so people can see it from 700 feet away. I can't use ordinary RGB LEDs (pixels)so enter image description here I'm using 3 watt pixels. ...
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2answers
93 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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1answer
59 views

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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3answers
222 views

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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3answers
138 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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2answers
68 views

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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1answer
45 views

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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47 views

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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1answer
75 views

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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199 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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7answers
1k 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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1answer
42 views

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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247 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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2answers
63 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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101 views

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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58 views

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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1answer
72 views

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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4answers
648 views

74HC595 8x16led matrix arduino

I'm currently trying to learn how multi shifting is working and have therefore started a project where I wanna drive 2X 8x8 LED matrix with an Arduino. I have found it that I should work with the ...
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106 views

Best practice to switch on 4 power supplies from one single source

First of all, I am a self taught maker with a passion for LED lights. So far I have built a few display signs for indoor applications, where one microcontroller is connected to a number of RGB Led ...
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1answer
246 views

Led Matrix multiplexing: sinking/sourcing current + LED brightness

I am trying to make an 8x8 LED matrix (actually a bigger one, but for now it would be easier to discuss this more simplified version) and I have gotten too confused about a few things concerning the ...
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4answers
299 views

Wiring a 28 segment LED bargraph (to an Arduino)

I need to control a Barmeter 28 led bargraph via an arduino (Mega). I believe I have found the details of the component here: http://www.barmeter.com/download/bl28-3005sk04y.pdf (BL28-3005SK04Y) I ...
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425 views

Why can the IS31FL3731 only handle 32 RGB Leds when it can handle 144 Regular ones?

I am looking at using the IS31FL3731 IC in a project soon, but I am confused as to why the data sheet says that the circuit can only use 32 RGB LEDs when it can use 144 regular LEDs. The data sheet ...
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2answers
107 views

LED matrix - MOSFET driver leakage?

I have 4 common-anode RGB LEDs in a 4x3 matrix. I have a BSS138 on each of the red, green and blue cathode lines and a BSS84 on each of the anode pins. The power supply is 3.3v, which is close enough ...
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3answers
153 views

How to stop current leakage in LED matrix

I know that this issue has been discussed in this forum, but I am a beginner in electronics and I was unable to come up with a solution to my problem by reading the related threads. I am doing a 3x5 ...
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142 views

LED Matrix creation using resistors & MAX7219

I've been attempting to create my own LED matrix, but now I've plugged it all together I'm getting some unexpected LED's lighting up, it seems some are getting power when they shouldn't (not very ...