Questions tagged [shift-register]

Shift registers are used to convert a serial string of bits into parallel data, or vice-versa.

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SN74HC595 Shift Register Issue

I'm trying to use the popular SN74HC595 Shift Register, but I think something isn't right because when the bits are submitted to the register it comes out with something similar but not the same. #...
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Stuck making multi, many button, joysticks

I'm stuck, I figured I'd ask here for some help... Note I'm a newb and this is essentially my first Arduino project beyond blink... I'm creating Virtual cockpit panels for DCS World, using an Arduino ...
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Clear Timer on Compare or CTC in ATmega328P, Toggle OC0A on Compare Match

I want to use the CTC on the ATmega328P to play same notes with a speaker, a project that I find in this book. In the data sheet I read: For generating a waveform output in CTC mode, the OC0A ...
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46 views

Read the value of a register in arduino

I want to read the value of the register (8-bit). In particular I want to read the values of: The Timer/Counter - TCNT0 ( Adress 0x26 (0x46) ) The output compare registers - OCR0A and OCR0B. Is ...
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Problem using 74HC595 with ULN2803A as LED driver

For a final project I'm making a word clock using three 74HC595 registers and three ULN2803A transistor arrays as led drivers, as well as a DS1307 RTC. The program works great, except for one large ...
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409 views

74HC595 shift register not working

I got my Arduino kit a few days ago and I've been going through some of the tutorials. I got to the 8 LEDs with a shift register tutorial, where I got stuck. Nothing would light up after I plugged ...
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Why does it skip the first index - shift register issue

So, I wrote this code myself and I'm a noob on the issue. I did get my code working, but cannot understand why it has to be the way it is. int counter; int ledValue[] = { 1,0,1,1,1,1,1,1 }; void ...
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271 views

Shift register with relay board behaving erratically

I have a nodemcu connected to a shift register(https://www.amazon.de/gp/product/B07CHBYR7Z) to control an 8 channel relay board (https://www.amazon.de/Elegoo-Relaismodul-Optokoppler-Arduino-Raspberry/...
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313 views

shift register 74HC595 enable specific pin

Its driving me crazy for some couple of days now and i don't get the answer. I'm busy to setup a irrigation system with a shift register 74HC595 and a 8 channel relay board. I see a lot of sketches ...
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73 views

What value of resistance to put between the output of a 74hc595 and the LEDs?

I'm going to start a project to make an array of LEDs using the shift registers 74HC595, I've seen many tutorials and it's not really difficult using the Arduino plataform. The situation is as ...
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127 views

Flashing a specified digit 4x7 segment display and shift register 74HC595N

I have a project that is simply a relay timer. The code is not complete so you will see 'in progress' sections not related to my question in my code. However, my question is... I am creating a timer ...
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77 views

HEF4094 with 12v Vcc

Using old NXP HEF4094BP shift register chips, for the reason of fixing some old hardware. These chips were popular in the 90's because they could accept 3-15V VCC and directly drive series+parallel ...
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207 views

How to drive 16 stepper motors with Arduino?

I'm trying to drive 16 of these little steppers on an Arduino Uno. Each test driver uses 4 digital pins for control (2 for each coil) so that would be 64 pins I will need. I'm thinking either ...
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196 views

How does Peggy2 drive rows with 74HC154 Decoder?

Trying to program Evil Mad Scientist's Peggy 2 board without their Library. The board drives a LED Matrix with Source 74HC154 Decoder Sink STP16CPSO5 LED Sink Driver Schematic What has me ...
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How do I get status of contactors using Arduino (more than 50 contactors)

I am new to Arduino. Sorry if my question sounds wrong. Interest areas: Multiple devices inter-connected on the cloud. Single GSM for equipment in a typical panel connectivity for non-electrical ...
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282 views

for loop running infinitely

void writereg() { digitalWrite(latchPin, LOW); for (int i = 7; i >= 0; i--) { digitalWrite(clockPin, LOW); Serial.print("wswitch&&&&&&"); Serial.print(i); ...
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244 views

Connecting two analog multiplexers (CD4051b)

Is it possible to connect two CD4051b analog multiplexers together so that I can receive 14 analog inputs through them? Just by using one analog pin and three digital pins on the Arduino UNO.
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Additional Digital Input Pins

I require additional digital input pins for 5 PIR sensors. Can I use the shift register (74HC165) to read these input? And will I be able obtain real time values from all the 5 sensors?
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402 views

Overheating Shift-Register(74HC595)

I am working on a project where I need to use around 50 LED's connected to an Arduino UNO board. To begin with i worked on the tutorial provided by Arduino (https://www.arduino.cc/en/Tutorial/ShiftOut)...
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67 views

Having trouble with 74HC595 and Uno

Just picked up a couple of 74HC595 shift registers to use for my Arduino Uno, and I'm having trouble getting it working 100% of the time. My code is to get a value from the Serial monitor and shift it ...
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2answers
793 views

Using SPI and 2 shift registers WITHOUT libraries

Arduino Mega 2560 board and SN74HC595 shift register(s). I'm working on a school assignment and having issues getting the shift register(s) working without using Arduino libraries. I know with the ...
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667 views

Is there a way to shift through sensors

We are doing a project and have to use around 25 temperature sensors. Is there a way to shift through them on one Arduino similar to using a shift-register? It is a set of analog sensors in a fridge.
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Weird output from chained 74HC595 shift registers

EDIT 4/2/18: The Arduino tutorial schematics have been corrected! See https://github.com/arduino/Arduino/issues/6433 for that issue. I have a project where I am trying to load a 16-bit number onto an ...
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237 views

Can I power my shift register with a 12V external power supply and connect only the data, strobe and clear pins to the Arduino digital pins?

I'm using a CD4094 shift register to power my LEDs along with a ULN2003A darlington transistor array. I want to hook up the LEDs to an external power supply of 12V (common anode). The cathodes of ...
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416 views

How do I choose proper diodes for a 74HC595 shift register with a wired OR connection?

I want to use a wired OR connection to connect some pins of the 74HC595 shift register to an Arduino Digital Input Pin. How do I choose proper diodes for this situation? Maximum rated forward current ...
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2k views

Are the output pins on the 74HC595 shift register protected against shorting?

In the following schematic you can see that Q1 and Q4 both are connected to a Arduino's Digital Input Pin. So if Q1 is high and Q4 is low, would there be current flowing from Q1 through Q4 (and ...
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853 views

Is the ShiftOut tutorial on the official Arduino website really wrong regarding the capacitor?

I'm talking about this tutorial "Serial to Parallel Shifting-Out with a 74HC595" from the official Arduino website. It provides the following schematic: I've read a couple of times now, that the ...
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240 views

Shift Register 74HC595 circuit working weirdly

I built the circuit from the arduino ShiftOut tutorial, but it is not working as expected. I made a simulation model and that one isn't working either. The code I used is from the tutorial: // SH_CP;...
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26 views

Can I control a Z84 counter timer circuit with Arduino?

Link to pin description and to the Datasheet. I'm thinking about connecting channel outputs to LEDs and control the clock with IO-Arduino or a 555: I would program it with a 595 register. Can ...
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45 views

Odd RGB matrix behavior while using shift registers

so I'm playing around with an 8x8 RGB matrix using a 74HC595 shift register for each of the colors. I've done this before with single color matrices and everything worked fine, but here I'm getting ...
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110 views

Advanced I/O shifting bits [closed]

I wanted to tinker around more with the 8-bit shift register (74HC595) so I tried to make a simple LED display and after reading about some shift commands I got lost and didn't understand much... Let'...
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620 views

ATmega328P SPI Slave

I was scrolling through the ATmega328P datasheet when I came across a rather fascinating statement about the way in which the data part of the SPI interface is buffered. I can't seem to understand why ...
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952 views

More than 500 pins

For a project I need 400-1000 pins controlled by one arduino. Each pin should work similar as arduino pin, so something like 5V, 90mA. Is using dozens of shift registers a good idea? And what power ...
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1k views

Need a proper diagram to connect my multiple relays (more than 8) with only a few pins on Arduino Uno Board

Specifically, I want to add multiple relays (approximately 36 to 40) to an Arduino Uno board (using only a few pins). I found a solution using ShiftOut. You can take a look here. But here the example ...
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746 views

What shift register would I need for input OR output?

Background: A few days ago I received a 23LC1024 1Mbit SRAM chip, which works like a charm. However, before I ordered that one, I ordered a LP621024D-70LL which also is a 1 Mbit SRAM but in DIP32 ...
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136 views

DS3231 AT24C32 IIC making digital outputs not work

I have just taken the code from https://learn.adafruit.com/adafruit-ds3231-precision-rtc-breakout/wiring-and-test to get DS3231 AT24C32 IIC to work fine with my Aduino and its working fine. I have ...
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822 views

Light up more than one LED connected to 74HC595 Shift Register

I have a 74HC595 Shift Register with a LED (and resistor) on each of the 8 output pins. I can light them all up I can light one up How do I light two up? For example the one on pin 2 and the one on ...
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392 views

I think I have a bad batch of TPIC6B595

I want drive a large number of LEDS from an Arduino Pro Mini using a number of TPIC6B595. I purchased these on ebay, perhaps a mistake. Initially I connected two TPIC6B595 as I would connect 74HC595 ...
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139 views

Problem with shift register

I have a problem with the shift register 74HC595. The sketch I use is able to enable a specific led (8 are connected). When I enable led 0 to 7 it behaves like normally (they switch on when I enter ...
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Is there an advantage to set pinmodes via bitmask and register?

I'm working with the capacitive sensor library currently and the author does not use digitalWrite(), but instead sets the output of a pin via functions changing the bitmasks of certain registers: ...
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856 views

shiftOut using SPI isn't working

I made a sample using two of them using Arduino UNO. So I did that like this: (There aren't any resistor on that image, but there are 220ohm resistor on every LEDs.) And uploaded this code. //1.6us+...
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390 views

Arduino uno shift register

I have shift register 74HC595. I added 7 push buttons from Q1-7 and the 8th to ground. On the other side which pin of the register will go to Arduino pin 2? And wich one to the 5v pin? How can I read ...
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524 views

Long Distance Shift Register

I am using a Mega to control some relay boards. I have a 16 relay board near the mega, and I want to put an 8 relay board about 40 ft. away. So I figured I could use a shift register - instead of ...
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1answer
71 views

Read time digits from DS1307 and run code based on return

I am currently reading a DS1307 adafruit breakout board and I need to drive two nixie tubes from a shift register. The shift register is running two 74141 IC chips. I have code that loops through all ...
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493 views

Multiple If Conditions Arduino

I have a project which requires me to read if the input is "HIGH". I have 15 inputs (switches), and each input has its own output (LED). I am using a Shift Register to control its inputs and outputs. ...
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871 views

Formula for current through shift register

Hi I am programmer that just started learning electronics and Arduino. I built this simple circuit on Autodesk Circuits earlier. Originally I used 220 ohm resistors. Then when I ran the simulation ...
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57 views

Seamlessly loop through LED's - Shift Register

I am using the following code to create a snake-like affect (3 LED's wide) moving through 24 LED's using 3 shift registers: for(int i = 0; i < 27; i++){ setRegisterPin(i, HIGH); ...
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843 views

Arduino, 74HC595N, magic

Good day I'm playing with Arduino and shift register chip 74HC595N and already tried many different ways to solve my problem, but still to luck :( So that is my current simple scheme: Arduino 2,3,4 ...
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1answer
558 views

Strange behavior on 74HC595 Shift Register IC when its GND pin is used

I was following a tutorial similar to this: https://www.arduino.cc/en/Tutorial/ShiftOut That is, an array of 8 LEDs that lit up accordingly to the binary representation of a number, which was given ...
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550 views

Maintaining pull down on a relay with a shift register

I currently have an Arduino Mega project that uses a relay to switch some high voltage loads. Currently, I use a scheduler library so that every 250ms I check if certain conditions are met and if so I ...