All Questions
486 questions
-3
votes
2
answers
76
views
What does VRx stand for in the KY-023? [closed]
The x and y axis pins on the KY-023 are labeled VRx and VRy, but I'm curious as to what they stand for, as I couldn't find any official statements about it. I assumed it was "Variable Resistor X/...
- 105
0
votes
0
answers
35
views
Reassigning GPIOs 6-11 on a 30 pin ESP Wroom 32
I am trying to wire up the ESP 32 based Crunch-E keychain synth (gituhub repo with wiring diagram here).
In my case I am using a 30 pin ESP Wroom 32 board with pinout diagram here.
The Crunch-E wiring ...
- 101
0
votes
0
answers
134
views
ESP8266 Not Booting Properly on First Power On – Works After Restart
I'm working on an ESP8266-based water level monitoring system using an ultrasonic sensor and an I2C LCD. The problem I'm facing is that sometimes the ESP8266 does not boot properly when powered on for ...
0
votes
1
answer
224
views
STM32 PWM on standard GPIO pins
I'm using an STM32F407ZET6 with the Arduino core support in PlatformIO. CPU has an external 8MHz crystal running at 168MHz. I have a project where I'm already using UART1, I2C1, SPI2 and SDIO (1Hz ...
- 61
0
votes
2
answers
89
views
Using TX as gpio, while using RX as serial pin to read data from other uC - Arduino atmega8
I am having a circuit that I am using the RX pin to receive data (int) from other uC (ESP12E) as one way communication, and for the lack of pins I had to use the TX pin as GPIO for a digit of a seven ...
- 11
-1
votes
2
answers
524
views
Open drain without pull-up
Looks like I didn't make myself clear, sorry. Update to clarify things / TL;DR version:
4 Arduino UNO pins are connected to respective DE-9 pins, responsible for UP, DOWN, LEFT, RIGHT directions
...
- 3
-2
votes
1
answer
199
views
Controlling Vintage floppy drives
After researching a solution to a problem I want to solve, I'm hoping the third time posting is a charm. :)
I'd like to use an Arduino to control a vintage floppy disk drive. I'm looking to use it as ...
- 1
0
votes
2
answers
437
views
How to Identify pins connected to each other?
There is probably another way to achieve what I want without connecting pins to each other, so I will explain the scenario:
I am trying to build an Arduino based Enigma Machine. The cryptography is ...
- 23
1
vote
3
answers
961
views
Confusing Pinouts on MH-ET ATTiny88
I am a little bewildered about the analog pins on the Arduino ATTiny88.
First of all, am I correct in thinking the functions analogRead() and analogWrite() can use either the string A0 - A7 or a ...
- 113
-2
votes
2
answers
94
views
Physically passing through a pin to access another [closed]
I would like to know about physically passing through a pin in order to get to another. For instance, if I have a sensor on one side of an ATMEGA328P or ESP8266 (Wemos D1 Mini) yet need to connect to ...
- 41
3
votes
2
answers
543
views
Why isn't pin 6 on my Adafruit Feather RP2040 being sent high when I ask it to?
I have an Adafruit Feather RP2040 (pinouts) connected via pin 6 to a relay. The code (below) triggers the relay when a separate color sensor returns "enough" red values.
The color sensor ...
- 169
0
votes
2
answers
173
views
Just one more pin!
I have an Arduino project to control a motor's speed at 3 levels, indicated by 3 LEDs, so level 1 is speed 1 and LED 1, and so on for levels 2/3.
Also, I added a low-battery voltage indicator to ...
- 111
1
vote
1
answer
99
views
Weird behaviour with BearSSL on GPIO ESP8266
I use GPIO 5 to trigger a relay. My code also connects with a secure MQTT connection for which I have to use the BearSSL certificate definitions.
Without the BearSSL certificates, when the ESP ...
4
votes
2
answers
1k
views
Trying to resolve invalid conversion from 'byte' {aka 'unsigned char'} to
I'm trying to use an existing Arduino library on the Raspberry Pi Pico. The library is here:
https://github.com/j-bellavance/EdgeDebounce/tree/master
It's based on some interesting insight at Jack ...
- 43
1
vote
0
answers
100
views
Selecting the Right GPIOs
I've bought this 4 relay ESP8266 board to active lights and window shades.
In an odd way - its relays are not pre-connected to a certain IO's but let you choose which IOs will operate relays (by ...
- 1,049
2
votes
2
answers
556
views
Barebones AVR - Connecting RESET pin to Vcc
I want to build my first barebones AVR circuit.
I plan on NOT having a RESET button. For this reason, is it valid if I connect the ATMEGA's RESET pin to Vcc directly?
What I mean by this, is that in ...
- 1,435
4
votes
1
answer
129
views
Can I use regular pins (Example: D2, A3, etc...) as serial (RX, TX)?
Python/Arduino Beginner here...
I have a DFplayer I am trying to hook to my Arduino and I want to hook it up through the regular pins instead of the RX and TX pins, but I've not been able to find ...
- 41
2
votes
1
answer
360
views
Remap SPI functions to default pins Arduino Zero via software?
I am looking at the documentation for the Arduino Zero, and I am a little confused.
It indicates that pins 13, 12, and 11 can be used for CIPO, COPI and SCK, but using SPI.begin() puts the signals on ...
- 21
3
votes
0
answers
433
views
Raspberry pi pico (Arduino core) not initialising SPI correctly for NRF24l01
I'm working on a project where i have a Raspberry pi Pico connected to a NRF24l01+ to send some data.
However i'm not recieving any data on the reciever and i think that its because the SPI bus is not ...
- 111
2
votes
1
answer
208
views
What type of pin header is this?
Most of the Arduino uno boards have black female pin header. when i bought a ardiuno uno the digital pins 0 to 7 are made of silver pins. What type of pin header is that? How to use these kind of pin ...
-3
votes
1
answer
322
views
Read status of digital pin 11, when it is set as OUTPUT
I have set pin 11 as output.
pinMode(11, OUTPUT);
However, I want to be able to read its state (if it is HIGH or LOW), however since it is set as OUTPUT, I am not able to use digitalRead().
I found ...
- 1,435
0
votes
3
answers
2k
views
How to Protect GPIO when using long wires?
I want to connect a normal toggle switch with one of the gpios pins of a tasmotized esp01 with a wire about 20 feet in length. When I tried this before, I lost the GPIO pin mostly due to the high ...
-3
votes
1
answer
2k
views
If Arduino digital pins can be used as power supply pins then why do we need VCC pins? [closed]
If Arduino digital pins can be used as power supply pins then why do we need VCC pins?
VCC pins work the same as digital outputs , don't they? So why do we still need VCC pins to
power components
0
votes
1
answer
596
views
Duinotech ATTINY85 Pinout
I'm sure this is a super nooby question but,
what is the pinout of the Digispark ATTINY85 Development Board
The board looks like this:
Now the reason why I'm asking this question, when I do ...
user87224
0
votes
1
answer
431
views
Why doesn't my mcp23s17 interrupts work anymore?
I'm using a teensy 4.0 with two mcp23s17 gpio expanders where #1 has 16 buttons wired to it, and #2 has 4 buttons and six rotary encoders. To run everything I'm using majenkos mcp23s17 library. ...
- 271
3
votes
1
answer
717
views
I'm using nRF2401 and in my transmitter and receiver the Rx is not blinking and Tx is blinking; why does Rx not blink?
I did a search on the meaning of RX and TX and it seems TX means sending data and RX means receiving data.
So when my transmitter is turned off, my receiver looks like this and it works with a battery:...
- 31
2
votes
1
answer
2k
views
What components can be connected to pins 0/1 (RX/TX) without preventing uploading of code?
For a robot project I am using an Arduino Uno, and am running out of pins. The simplest solution would be to use digital pins 0/1. I know this means that I won't be able to use Serial communication (...
- 31
3
votes
1
answer
219
views
Why am I reading only zeroes from PORTB?
I am using a custom Arduino Nano compatible board with an Atmel 328P. I am externally changing the values applied to several pins on PORTB. I expect to be able to read the values of these pins (low ...
- 33
2
votes
1
answer
193
views
Safe to solder a slide switch to unused GPIO pins?
I have a Digispark Rev.3 Kickstarter with ATTiny85 (see pinout below) and a three pin slide switch (see example below). I want to use the slide switch to control a task running on the Digispark, with ...
- 105
3
votes
3
answers
15k
views
How to toggle a pin (LED) simply
I am not a programmer but rather a hardware guy. In the good old machine code days, you could 'read' the status of the port and flip it.. admittedly a much simpler processor. Is it not possible to do ...
- 41
0
votes
1
answer
799
views
How do I instruct the L293D to operate a motor at full speed when using 3.3V GPIO pins?
If the L293D enable and input pins expect [up to] 5V inputs; what is the best way to deliver full power to the output pins when using an ESP32 or any other microcontroller which uses 3.3V GPIO pins?
I'...
- 115
-1
votes
1
answer
3k
views
How to use ESP-01 GPIOs for input?
I'm trying to use one of ESP-01 GPIOs as an input, however, I'm always reading 1 and nothing attached to these pins.
Basically, I'm trying to detect high voltage from another sensor like a touch ...
0
votes
1
answer
82
views
Can pin mode damage Arduino with connected electronics?
I am not that experienced with electronics, so this might be a silly question. But I dont know. Assume that I have connected some electronic circuit (transistors, leds, anything else) to the Arduino ...
- 113
1
vote
0
answers
134
views
Can I use AREF to supply a circuit, when in internal mode? (Nano)
When analogReference(INTERNAL) is set (1.1V), can I use the AREF pin to supply a circuit? E.g. like this:
AREF —— R1 —— button switch —— A4 —— R2 —— GND
where A4 is configured as analog input (...
- 111
11
votes
3
answers
12k
views
Why are the pin numbers of the diagrams and of the code different?
If I search Google for "arduino nano pin numbers", all results show that the pin number of D2 is 5. But that did not work. I searched for some sample codes, and they were 3 for D3 and 5 for ...
- 357
0
votes
1
answer
693
views
Problem Using pins A4 and A5 for input and output I2C
Hardare used:
Arduino nano ( old Bootloader )
Oled Monochrome Display ( 4 pins, 128 x 32 )
MPU 6050
Both display and MPU use A4 and A5 as I2C communication protocol, They interfere, as the MPU is used ...
- 11
4
votes
1
answer
1k
views
Arduino UNO won't move servo
I have a simple MG996 servo motor and I am trying to make it move with my Arduino Uno. I tried different ways of wiring but nothing seems to work as fully expected.
For the wiring I followed this ...
2
votes
2
answers
7k
views
Input vs input_pullup
I'm a beginner in Arduino and can't understand some things. How does input pin in Arduino work? I want to set one of the pins as input. When should I use input and when input_pullup? What are the ...
- 51
0
votes
1
answer
1k
views
Safe to power LED strip via ESP32 GPIO
I want to rewire a battery powered LED strip (as shown in the picture below) to power via an ESP32's GPIO pin. I have a ESP32 NodeMCU Development Board, powered via USB.
The LED strip has specified 3,...
- 105
1
vote
0
answers
67
views
Can I support all these sensors? Will I have enough pins?
So i'm new to arduino and i'm working on a project that will require 3 modules/sensors.
I wanted to know, can all of the following modules work with the arduino mega 2560 that comes with this
touch ...
- 11
4
votes
1
answer
83
views
Custom LED toggling function: one out of three LEDs misbehave
I connected three LEDs to an Arduino Uno and wrote a simple LED class. I toggle all the leds the main loop, but for some reason one led (connected to pin7) always misbehaves, skips one toggle or stays ...
- 73
1
vote
1
answer
897
views
Select pin to connect RF receiver
I use the RCSwitch library receive signals with a RF receiver. I really need to change the pin the receiver is connected to on my Arduino Uno.
What should I change in my sketch?
What pins can I ...
- 139
1
vote
1
answer
511
views
Accessing Physical Pins in Arduino Due from Arduino IDE
It is possible to access the Physical Pin 93, Pin PC11 on ATSAM3X8E in Arduino Due from the Arduino IDE?
I am programming a Barebone ATSAM3X8E, and it do not seems to be allocated by Arduino Due nor ...
- 337
5
votes
1
answer
203
views
Wirelessly (but fast) transfer STEP and DIR output from Arduino to stepper driver
Very short version:
Looking for a way to wirelessly get STEP and DIR signals (only those two signals) from an Arduino to a DRV8825 stepper driver about a meter away:
Arduino -> STEP and DIR IO pins ...
- 151
1
vote
1
answer
1k
views
How to connect an Output to a Pullup Input of another arduino
:tldr; Could problems occur if one connects a HIGH Output of one arduino to a PULLUP_INPUT of another while using differed power sources?
Hi I'm building some devices for a LARP Dungeon (think Escape ...
3
votes
4
answers
2k
views
Can internal and external pull up/pull down resisters be used together?
What happens if a sketch uses code like pinMode(18,INPUT_PULLDOWN) to configure internal pull-down (or pull-up) resistors, but is used in a circuit where external resistors are also present?
Are there ...
- 200
0
votes
1
answer
140
views
Check pin capabilities at compile time
Are there board-independent functions to check pin capabilities at compile time? I.e.
Can the pin be used as output, as in digitalWrite()?
Does the pin support PWM, as in analogWrite()?
Does the pin ...
- 1,288
1
vote
0
answers
41
views
How to avoid two arduino components using the same digital PIN [duplicate]
I'm trying to build an Arduino project where it involves a TFT and an ethernet W5500 component.
Here's the project I want to build to learn Arduino. However I wanted to change the board that already ...
1
vote
0
answers
71
views
Can I create an hemi-cycle raising signal with one pin and the other hemi-cycle signal with another pin?
I am new to Arduino, I would like to know if someone could help me to create this type of signal with the Arduino Uno. Many thanks!!
- 11
1
vote
0
answers
55
views
Touch sensor trouble
I need help I use Touch Sensor(T)v.0 and it always receives a signal not matter I touched it or not.
Here is the code.
#define TOUCH_PIN 7
int touchVal = 0;
void setup() {
Serial.begin(115200);
...
