Arduino

Questions tagged [digital]

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Digital refers to signals which are either on or off (high or low, one or zero). This contrasts with analog signals which have a range of values.

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Nano: All digital pins do not output anything

New user here. Using the examples provided on the Arduino IDE software I could produce melodies with a piezo buzzer, or have a blinking LED. Not anymore. No digital pin is giving anything. I can see ...
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52 views

Is it possible to overload the digital pins for an Arduino?

I worked on an Arduino project for school that was a self-driving security robot that also acted as a smart home system. It was essentially a self-driving Roomba-like car that included several LED's(...
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29 views

Confused as to how 2 of my interrupts are firing from just 1 pin input?

I have the following code which uses interrupts to set a flag for whether serial IO should happen to update my PC about a particular pin input. So I have interrupts on pins 2 and 3. I am using the ...
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55 views

Is my Arduino skipping a statement?

So, I made this code (I'm rather new to this). The only thing that the Arduino should do, is when I press the button on pin 2, turn on the LED on pin 4 and emulate CTRL + R on the keyboard for the ...
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1answer
188 views

DHT11 analog or digital?

I saw some projects with DHT11, some connect it with analog pin, others connect with digital pin. Is there any difference / advantage connecting to the analog?
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1answer
31 views

Dynamically control the output voltage of a 60V DC input

I am hoping to control a 60V DC input source dynamically using my Arduino so that the output voltage could vary between 0v to 60v. At first i was looking into digital potential meter, however I couldn'...
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46 views

Read amount of I/Os in code

I want to write an Arduino code, that runs on several different Boards. The code can perform digitalRead/Write operations, but the pin number will be set from the user/outside. I want to include a ...
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32 views

write from one board's pin to read of another's not working

I have an Intel Tiny Tile boardThis board is based on the Intel Curie, and can be read in Arduino as an Arduino 101. I'm using this board's accelerometer to register the bounce of someone on a ...
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2answers
65 views

Is it possible to use the Arduino Due's specials pins for digital writing and reading?

Hello the arduino documentation on the due specifies the pin mapping of the pins.I am making a custom board using the dues schematics and i am running still a bit low on pins. Also some of the special ...
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1answer
52 views

How can I read this digital pin for Nano by using AVR's Atmel Studo?

How can I read digital pin 6 in AVR? I set the pin as input as follows: DDRD = B0100000; //this will set pin 6 as input But how can I now digital read this pin?: Another way of putting it: how can ...
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1answer
199 views

How to count positive electrical pulses?

I have a device that has one blinking LED. I want to count the number of blinks. I planned to do it using Arduino. I will connect two terminals of LED input to Arduino digital input pins, and I will ...
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81 views

Help combining digital and analog code in arduino programming

So I'm making a device that does 3 things, Measures frequency of an audio signal through a microphone Checks whether there is a weight placed on a pressure pad (my pressure sensor works through the ...
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126 views

Red LED not turning off on Adafruit Circuit Playground Classic

When using the traditional Blink example program, the light blinks as expected. Even when writing from scratch digitalWriteing pin 13 to high and low repeatedly works fine. The problem is when I try ...
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43 views

`LOW` being defined as `0` and `HIGH` being defined as `1` - is this a part of external specification?

Arduino.h defines LOW as 0x0 and HIGH as 0x1. Does the Arduino API intend to expose that fact? Does it guarantee that this will always be that way? In other words, what is the intended purpose of ...
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116 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 ...
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86 views

Cannot write pin LOW

All the other examples I've seen have had coding errors where they set a pin LOW in a loop with no delay so that it goes high again right away - but this problem is different, and probably something ...
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562 views

Using a water sensor with a NodeMCU make it less sensitive?

I'm trying to digitalRead from a water sensor (the one in the picture) using NodeMCU v3,when I try the sensor with an Arduino board it works fine, but when I try it with an ESP8266 NodeMCU v3 it ...
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49 views

Can I read using an analog pin on an arduino Mega whether or not there is a high (5v) voltage on a wire from another board's digital pin?

I am making a peer-to-peer network of initiating devices and a common hub, which controls most of the hardware. It sends a number over Serial to Mega's Serial1 (Mega's Serial is used for communicating ...
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1answer
416 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 ...
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55 views

Is my code triggering the N-Channel MOSFET as I have intended to

I have a certain bit of code that I believe after 10 seconds will send a high signal to the second digital pin for 50 seconds. After it will not do anything. For some reason the nichrome wire is not ...
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2answers
621 views

Analog vs Digital Accelerometers - pro's and con's? [closed]

For my project i need to measure accelerations up to 16g. My options are either digital accelerometers such as the MPU6050 or MPU9250 or an analog accelerometer such as the ADXL326. What are any ...
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76 views

How can we use two devices at the same time with arduino?

I am using fingerprint module r307 and LCD together. In that, I am using 2,3 digital pins of arduino for data transfer to the fingerprint.(I tried other pin configurations for this but it didn't work) ...
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37 views

Elapsedtime variable not resetting

I am new to Arduino programming. Let me describe the application I am working on. I am pressing a button for a certain period of time (30 sec). I can not hold it in a pressed position for all the time....
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1answer
100 views

Routing Matrix with a large number of I/O [closed]

Lets say that i would like to make a 128x128 routing matrix with an arduino uno, Since i am unexperienced i think of using two 4051’s for 8x8 patching and because i want to persist the patch, ...
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178 views

Arduino UNO LED half brightness when connected to digital GND but not analog [closed]

I am using an Arduino UNO. When lighting an LED with the switch button on a joystick module, I have two situations: If the LED's cathode is connected to GND on the digital pin side of the Uno, the ...
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2answers
2k views

Sending a digital signal from one Arduino to another to trigger an event

I am wanting to send a digital signal from one Arduino to another. The goal is for one Arduino send a HIGH signal to a pin on the receiving Arduino. While the pin is HIGH, do function I initially ...
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1answer
3k views

Read frequency of input in digital pins

This is a somewhat theoretical question: Let's say I have some sensor that sends digital signals to one of Arduino's digital ports. Now, I don't know the frequency it sends those signals in. For ...
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3answers
65 views

For Arduino, is there a meaningful difference between carriage returns?

Serial.write(0x0d); // hex Serial.write(13); // ASCII Serial.write('\r'); // char Is one more efficient? I read how it depends on the terminal program. So does that mean the IDE? (This is my ...
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2answers
518 views

Digital Sound sensor

I am having trouble with my digital sound sensor. My goal: Clap 2 times and a led goes on. So I wrote this code. I don't know if it is correct or not. This happens: If I clap, from the serial monitor ...
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1answer
50 views

Error in finding frequency of an input signal

Here is my code to find the frequency of an input rectangular wave at pin 8 of the Arduino Uno board. const uint16_t freqPin = PB0; const uint16_t load = 0; unsigned long int count=0; unsigned int ...
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1answer
38 views

Digital selection for gain control not working instead showing 0

I am making a device which will have a button to measure the input and another button to reset and the inputs are variable analog values(0 to 5v) and output is a ratio of two analog input voltages. It ...
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1answer
145 views

How to digital read and send the data through serial to PC with speed around 2 MHz?

I would like to read analog data with frequency sampling around 2 MHz and send it to PC to be processed with python for digital oscilloscope. I use Arduino Nano. I have found ADC (AD9057, PDF) that ...
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2answers
704 views

Digital Band pass filter arduino 1100-1300 Hz

For a project I need to design an digital band pass filter. I started of with this in Matlab: wch=1100*2*pi; wcl=1300*2*pi; sys=tf([1/wch 0],[1/(wch*wcl) 1/wch+1/wcl 1]) sysd=c2d(sys,9615,'tustin') ...
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53 views

Upcoming Project [duplicate]

Hey guys I have a project that will require 20 I/O pins with serial communication from a computer to control each of the pins. I would like something as small as possible would a arduino micro or uno ...
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1answer
499 views

4x4 matrix keypad - Multiple inputs cause extra readings

I have the following matrix keypad - I am using this as a sort of controller with my Arduino (Mega2560) but I can't get real multiple inputs to work. I am able to have say two individual keys ...
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2answers
79 views

Where can I find the complete list of Arduino Serial Command & Query Strings?

I am planning to use the Arduino as a replacement for a USB-Controlled Digital I/O device, which will be integrated into an existing C++ software package that I created. I understand that the Arduino ...
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3answers
916 views

Fool Proofing My Arduino IC Checker [closed]

I am creating an IC checker for some high school juniors since a faulty IC can be a nuisance of a bug to find when bread-boarding. These ICs are all simple TTL gating from the 74LS series; the set I ...
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1answer
57 views

Light Powered Motor Troubles [closed]

I'm working on a small car (<1 kg) which will drive when there is light and stop when there isn't. Below is a plan with code drawn up (the only numbers I know for sure are the current gains for the ...
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1answer
169 views

Consequences of dynamically changing input/output configurations of digital pin?

I am creating an IC checker for a large chunk of the 74ls series (basic TTL logic chips), which means that I have 14 pins running to the IC to verify its functionality. One pin is power (+5V) and ...
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3answers
1k views

digitalRead keeps giving 1

I am new to arduino programming and I have bought arduino UNO a few days ago. I am trying to read the value of pin 4 using digitalRead with pinMode INPUT_PULLUP but it keeps giving me 1 even when the ...
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1answer
453 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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167 views

Need to “Extend” a Arduino Digital Signal

Here's the scenario: We have 1 arduino uno accepting DMX and converting that to a signal that is being sent out digitally (PIN 3). The digital signal then goes to several IR LED senders that control 3,...
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2answers
31 views

Powering via an I/O Line

I have an SPI 128x64 OLED display. Is it safe to power this display's VCC from a digital I/O pin? I would like to do this so I can connect it flush to my arduino's header, and so I can control the ...
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1answer
238 views

Why would digital outputs on Arduino Due be less than 3.3V?

We are working on a project that requires a temperature sensor to tell the Arduino Due to turn a digital pin to HIGH (3.3V) to active a relay so a heating pad can be powered on. We have diagnosed all ...
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2answers
860 views

Controlling an MCP41HV31 Digital Potentiometer

I need to control a 10kOhm digital potentiometer in rheostat mode in 256 steps. I found an Arduino tutorial, which works with an MCP41010 (I added a viper resistance according to the datasheet). This ...
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2answers
226 views

Arduino-based mains frequency monitor follow-up

Following my previous question, I'm getting closer to thinking about putting together this mains frequency monitor. I would just like to do a sanity check on my electronics before I order the ...
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5answers
642 views

Arduino-based mains frequency monitor

I'm looking to put together a simple mains frequency monitor based on the Arduino platform. The mains here are 250 V @ 50 Hz, but obviously these fluctuate slightly, which is the whole point of the ...
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2answers
355 views

Why digital pin not reading ON from push button switches connected to 5V and pull-down 10K resistor?

Here's my circuit: And the code: //pins const int control1 = 2; const int control2 = 3; const int enable = 9; const int pinDirection = 4; const int pinOnOff = 5; const int pot = A0; //states ...
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1answer
481 views

Too low voltage on digital input on attiny45

I'm using one of my attiny's pins as digital input. I use it with a pulldown resistor. As input I use simple square wave generated by a separate waveform generator. igh state for square wave is 5V, ...
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1answer
760 views

Arduino Control TV over RS232

I have a LG TV(LG 32SL800 ZB), which has a RS232-Port for Control and Service. And I am wondering if I could control this port with my Arduino (NODE-MCU) and a module like this one RS232 Board? How ...

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