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Questions tagged [digital-in]

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Fast digital IO

I have a device programmable via an 8 bit digital parallel bus. I would like an Arduino to translate from a parallel 4 bit output of an existing device to 8 bit by intentionally reducing the ...
P. Egli's user avatar
  • 121
0 votes
3 answers
103 views

Cannot read LED state

I am running into a problem on a very basic functionality. I want to read the state of an LED. I have confirmed that under the specified circumstances, the LED receives 1.9V. I try to read its state ...
user1584421's user avatar
  • 1,405
0 votes
2 answers
315 views

Read Digital Input from Arduino Pin defined as OUTPUT

I'm working on a Home Automation Project. I can turn on-off ESP32 pin from Alexa and Google Assistant Successfully now. What I need help is with a way to read if the AC supply is ON/OFF on the Arduino ...
Just doin Gods work's user avatar
1 vote
2 answers
94 views

arduino mega buzzer output

I have project by Arduino mega which have 22 inputs and 22 outputs and buzzer reset and output reset pushbuttons , it have two status if the input is high(not continuous ) the output will on and the ...
eng.hamza's user avatar
1 vote
3 answers
134 views

How long does my digital pulse need to be for it to be read?

I have the following really simple code. On every iteration it'll read the first pin, and if it's high - do some serial IO. Then do the same with the second pin. Nice and simple, works during my tests....
JᴀʏMᴇᴇ's user avatar
0 votes
1 answer
2k views

How can I scan for a HIGH signal on digitalRead during the main loop, while running other things?

I'm working on a program which listens for certain bytes on serial through an if/then/elseif ladder. I want to also check if a pin (say, A15) has been given a HIGH state, by another Arduino with ...
SYGMAH's user avatar
  • 29
0 votes
2 answers
7k views

Using NodeMCU D8 (GPIO15), D4 (GPIO2) and D3 (GPIO0) pins

I am using a NodeMCU board and have already used 6 digital pins as output for interfacing with the LCD. I intend to use 2 more digital pins, one as input and other as output for interfacing an ...
maheshmt's user avatar
3 votes
1 answer
2k views

Digital I/O threshold voltages for ATmega32u4

What are the voltages on a ATmega32u4 (eg Arduino Leonardo) such that a HIGH or LOW is read? I want to ensure that I'm reading the chip reference manual correctly, where Table 29-1 says: VIL: Input ...
Tom Hale's user avatar
  • 431
1 vote
0 answers
116 views

Digital input on one pin is copied to other pins

I am working on a phase detection project in which i am trying to find the order in which the incoming signal comes. I converted the 240v 50hz Ac signal to a 7v 50hz square pulse. when i connect one(...
user2998792's user avatar
0 votes
4 answers
7k views

How much voltage and current can a Arduino uno digital input sink?

I am having a digital output of 24VDC and 0.5A from ABB IRC5 controller. I need to feed this digital output to the digital input of Arduino uno. How can I do that?
Sri Harsha's user avatar
0 votes
3 answers
308 views

How to monitor state of 50 Digital Inputs

Good day. I have a specific project need and I spent the past couple of days searching on forum, blogs, etc and I'm still not clear if that's feasible to do with Arduino or not. I need to monitor ...
Sergio's user avatar
  • 1
1 vote
0 answers
459 views

Correct wiring?

I'm doing some Home automation and am currently trying to automate my intercom system. My overall aim is to be able to detect when someone has pressed the buzzer and then to be able to open the door ...
Rocco's user avatar
  • 165
1 vote
2 answers
1k views

How to set sampling rate for digital pin input? [closed]

I have an ADC that have sampling rate up to 40 MSPS, but i use 8 MHz clock so it will be 8 MSPS. The board used is arduino nano. The problem is i have to sampling it just 2 MHz (because the capacity ...
Zahi Azmi's user avatar
-2 votes
1 answer
147 views

USB reset fails on arduino due because of 5v on digital pins

I have the signal channels of four 5v magnetic encoders connected directly to the digital pins of the arduino due. I am aware that this is not allowed according to the specification which says that ...
WhiteSpin's user avatar
0 votes
1 answer
107 views

Digital Pins reads 1 when configured with internal_pullup

I work with Arduino DUE. I would like to configure few of my digital pins as INPUT pins. When the µc sets these particular 4 pins , the DUE must be activated. Something like a DATAREADY pin in the SPI,...
kaya's user avatar
  • 13
1 vote
2 answers
2k views

Reading input from digital pins 36, 37, 38 in Arduino Mega 2560 is giving a problem

I wrote a program to read digital input from pins 36, 37, 38 and print on LCD when they go HIGH. I've connected those pins to a switch to test. The program looks like this: #include "LiquidCrystal.h"...
Aparna B's user avatar
  • 113
1 vote
1 answer
64 views

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?
0x000005A's user avatar
2 votes
2 answers
451 views

Mixing analog reads with raw port reads

I'm reading two digital inputs and one analog input. For [reasons] I must use A0 and A1 as digital ins, and A2 as an analog in. I'm uncertain about how the Arduino hardware deals with mixing analog ...
Jim Mack's user avatar
  • 235
1 vote
2 answers
763 views

Arduino digital pin reading string numbers

Using for example 433MHz RF Receiver modules, they are connected to a digital input pin with interrupt. Looking at the most basic meaning of digital readings (e.g. 1/0, on/off, HIGH/LOW), how does the ...
Renier Delport's user avatar
1 vote
1 answer
917 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 ...
Liam's user avatar
  • 77
-1 votes
1 answer
57 views

RasPi GPIO into Arduino Digital Inputs

So I'm making a Robot for my AP Comp Sci Class, and I'm borrowing an Arduino, as well as a Pi from the school. What I plan to do is have my Pi output from the normal GPIO pins and into the Arduino's ...
Ryan Louis's user avatar
3 votes
3 answers
12k views

At what frequency/rate does the digitalRead function read an input?

Consider the following code: void loop() { // read the state of the pushbutton value: buttonState = digitalRead(buttonPin); // check if the pushbutton is pressed. // if it is, the ...
user16307's user avatar
  • 237
2 votes
2 answers
4k views

Arduino read PWM duty cycle value with input (analog / digital)

I am working on comparing autopilots like Ardupilot, CC3D, KK2.1.5. The comparision is about system reactions/behaviors that it gives during flight. For this purpose, I need to read the PWM duty cycle ...
acs's user avatar
  • 235
-1 votes
4 answers
7k views

Reading multiple DI pins in parallel as one byte/word

I need to capture a single parallel 'snapshot' from a 10-bit shaft encoder. I understand that I can read individual bits and shift them into position, but any given input pin might change while ...
Jim Mack's user avatar
  • 235
0 votes
3 answers
622 views

Digital read on voltages between 1 and 31 volts?

Hello Arduino comunity! I am working on a circuit that uses an Arduino Mini to read values from certain points of a boost/buck converter circuit to determine things like input state, output state, ...
fillpant's user avatar
  • 103
2 votes
2 answers
471 views

Arduino - Turn on LED when Potentionmeter is used

I'm very new to the Arduino/Microcontroller-world, so please be patient :) I have 4 potentiometers and I want my LED to blink up, when one of these is beeing used. So far., so good.. the ...
crunchy's user avatar
  • 31
0 votes
1 answer
39 views

Can I close an input?

I wan't to build a diversity controller similar to this one. A diversity controller is basically a circuit which detects the strongest RSSI Signal of multiple receivers and provides the data signal ...
jawo's user avatar
  • 113
1 vote
1 answer
4k views

Digital input pin voltage treshold (voltage to register 1 or 0)

I was thinking of using multiple analog light sensors (variable resistance by light), but basically I only need to know if there is "a lot of light" or "not a lot of light". And would like to use ...
aaa's user avatar
  • 2,695
0 votes
1 answer
127 views

Having 3 buttons with only 2 input pins

for the purpose of learning, I'm trying to have a kind of digital/binary input where I'm using 3 buttons but only 2 input pins. I thought of 01 = Button 1 10 = Button 2 11 = Button 3 My first ...
lumio's user avatar
  • 103
5 votes
1 answer
5k views

ArduinoMEGA: 64 digital inputs cause random digitalRead values

I have 64 hall effect sensors (magnetic field sensors) (DRV5023AJQLPG) connected to an Arduino MEGA 2560. For that, I use 48 digital pins and 16 analog pins as digital input pins. The program in the ...
Edo Paulus's user avatar
-2 votes
4 answers
3k views

Can you connect ACS712 sensor to digital input of Arduino? [closed]

I have a home automation project and am looking to use multiple current sensors (ACS712) for multiple appliances. I just need to know whether current is present or not instead of the current value. Is ...
Aneesh Relan's user avatar
5 votes
1 answer
2k views

How to confirm a pin is fried

How do you confirm a pin has been damaged and is unable to work as a digital input? I tried detecting a pushbutton (connecting ground to pin 11 with a pullup resistor enabled) on a fresh Arduino Uno ...
Cerin's user avatar
  • 1,638
0 votes
2 answers
2k views

Comparators for digital input mode

I've asked another question in electronics about what to use to compare 2 input voltages, the answer was to use comparators. Digging around a bit, turns out most of the comparators outputs are pull-...
Deko's user avatar
  • 133
2 votes
2 answers
111 views

Are there any Analog pins on the mega that can not be used as Digital?

I am using both Arduino nano and Arduino mega boards in my projects. I got a nasty surprise the other day when I learned that, on the nano, Analog pins 6 and 7 can not be used as digital pins. Are ...
Hoytman's user avatar
  • 747
0 votes
2 answers
2k views

Reading a photoresistor

I have a wire with a 0-5v current. I want to detect if the current is there or not (HIGH/LOW.) I'm using an optocoupler to avoid putting too much current into my micro, as it is only a 3.3V micro. I'...
futurebird's user avatar
1 vote
4 answers
5k views

Best way to protect a digital output?

I am looking for a way to protect my Arduino's digital outputs from unwanted, outside voltages. My project uses about 20 different outputs, each connected to a wire (run) that can range from 20 to 100 ...
Hoytman's user avatar
  • 747