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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2answers
39 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
20 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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0answers
36 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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1answer
35 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
85 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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0answers
62 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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32 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
59 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
34 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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0answers
27 views

Led Board P10 32x16

I bought a board P10-3535-4S from China. I am trying to put it on with uC STM32F103. All the leds turn ON but can't get what I want. I did search to find the schematic of this panel. The only ...
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3answers
74 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
66 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
49 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
41 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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1answer
43 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
65 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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0answers
58 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
400 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
34 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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0answers
77 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
54 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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1answer
70 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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0answers
29 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
68 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
207 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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0answers
105 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
98 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
127 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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1answer
181 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
85 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
101 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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0answers
77 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 ...
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1answer
82 views

LED on and off indicator for solenoid

I have a circuit with a single momentary on switch that causes a solenoid to change position. I need to be able to see which position the solenoid is in. I've looked at the circuits for motor control ...
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1answer
35 views

What could be causing an unreliable output for 3 different IS31FL3731 chips

I have a board that uses the Adafruit breakout of the IS31FL3731 to control 81 illuminated switches. I have some code that runs on an Arduino that should turn all the lights on, but only about half ...
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2answers
158 views

Multiplexed LED column driver MOSFET doesn't fully turn off without a resistor parallel to the LEDS

I have a board with a 16x10 led matrix. The columns are switched with DMG9933 Dual P mosfets. The rows are driven with a constant current led driver ST STP16CPC26 (similar to TI TLC5956) I noticed ...
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1answer
44 views

How will current divide in a LED matrix in one select line when there are 8 data lines?

simulate this circuit – Schematic created using CircuitLab Let's say I have a select line that is connected to 8 data lines in an LED matrix. The current at the drain of the MOSFET is 800mA. ...
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1answer
190 views

Led panel sending and receiving card working

I understand how a RGB LED panel is driven from sparkfun's explanation (here). From manufacturers like Huidu and Novastar I get that in a setup you often need a sending and receiving card. Like you ...
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2answers
126 views

Led driver high current and voltage

For a project I have to design a led beacon that will consist of +400 LEDS. These LEDS will be driven only a short amount of time maximum of 3% duty cycle (frequency: 100Hz, pulse: 300us). The LEDS ...
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2answers
267 views

How does a dot matrix led driver know the voltage of an led?

I wanted to make a 7x10 led dot matrix using two 5x7 led dot matrix from lite-on (LTP757KR). I first thought of using shift registers, then I found a 12 x 8 dot matrix led driver with a bunch of ...
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2answers
1k views

Why does a 74HC595N work in LED matrices?

I have checked a lot of LED matrices, and mostly a 74HC595N shift register is used. In some cases a TPIC595B like below. Example: Driving LED arrays with Arduino Circuit from above example: I ...
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3answers
368 views

Do I need to split my GND lines?

I am intending to make a multiplexed LED matrix, possibly with 16 rows, 8 columns. This means maximum 16 LEDs (one full row) will be lit at the same time, thus 16 LEDs * 20 mA/LED = 320 mA. According ...
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1answer
1k views

Library for driving P10 LED Display with ESP32

I am trying to make a 10 digit cricket scoreboard for which, I want to use P10 LED modules as digits. My objective is to change the score from Mobile Phone via BLE. ESP32 microcontroller suits best ...
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1answer
54 views

What is sitting inside LED array so that I can create my own drivers?

I have a LED array and an app to drive it: https://itunes.apple.com/US/app/id1431362600?mt=8 https://play.google.com/store/apps/details?id=com.yskj.led&hl=en_US I connect to WiFi and I'm able to ...
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1answer
333 views

LED Christmas lights without limiting resistor

My LED Christmas light strings do not have a series limiting resistor, how is this achieved? They are 70 LED strings with two 35 bulb sections. I have carefully checked and there are no provisions in ...
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2answers
279 views

Multiplexing LEDs

I’m doing a 16X32 LED matrix system. Controls via a PIC micro controller. The whole circuit is operating from a 5V source. For easy understand I have drawn a single Row/column how my hardware is ...
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2answers
73 views

Can I use an LDO to control several diodes at a speed in the order of kHz?

I wish to control the switching on and off of several LEDs as indicated in the following figure: simulate this circuit – Schematic created using CircuitLab The bases of transistors and the ON/...
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3answers
722 views

LED Fault in PCB - Some strings of LEDs intermittently dim

I have a university project that involves working with surface mount LEDs. For some reason, some of the rows of LEDs, when lit up, are dimmer than they should be. This problem is only intermittent ...
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3answers
2k views

How do I get 5V 10A output from a 3.7V li-ion battery for 64x16 led matrix display module?

Please I am new to electronics and new here. I'm doing a project which involves the use of a 18650 li-ion battery (or two as may be the case) to power a 64x16 led matrix display module which (...
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4answers
3k views

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 ...
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1answer
99 views

How to protect LEDs from high voltage during NPN transitor transitions?

I am using a 555 timer and an NPN transistor to drive an array of 12 LEDs from a 9v battery, and a potentiometer to control the duty cycle. I am concerned about the voltages the LEDs will be subjected ...