Arduino Stack Exchange
Arduino Stack Exchange

Questions tagged [electronics]

Use this tag to ask about electronics-related issues with your Arduino. For example: driver transistors, Ohm's Law, current-limiting resistors.

This tag is for the hardware side of your Arduino project, particularly electronics questions. Relevant questions would be about:

  • Transistors
  • MOSFETs
  • Diodes
  • Resistors
  • Capacitors
  • Inductors
  • Current-limiting resistors
  • Ohm's Law
  • Power calculations
  • Switching devices on and off
  • Input protection circuits
  • Output protection circuits
  • Opto-couplers
  • Choice of components
  • Other electronics-related questions

Also see:

244 questions
9
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1 answer

Why connect a diode between the reset pin of Arduino and 555 timer?

I am trying to create a watchdog timer using 555 IC and I am following this. I do not understand why a 1N4148 diode is connected between the reset pin of Arduino and the output of the 555 timer. As far as I understand, the reset pin of the Arduino…
bukke hari prasad
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6
votes
4 answers

Programming standalone Atmega328p-PU with NE555N timer IC

I know I may sound a little idiotic to ask, but as I have seen in the internet that to program a standalone Atmel chip like that from of the Arduino's, you need 2 22pF ceramic capacitors and a 16mhz oscillator. As the oscillator is needed is clock…
Samanwaya Datta
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5
votes
4 answers

Why would the resistor be after the LED in this project?

This is project 2 of their official arduino projects book called "Spaceship interface". I understand resistors normally reduce voltage so the LEDs don't burnout but here 5v is coming from either digital 3, 4, or 5 and it seems like it goes right…
Nick D
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5
votes
2 answers

Voltage changes but digitalRead always HIGH

I developed a simple push button project I used a wemos D1 mini I connected D3 pin to a pull down 1K resistor. I used a multimeter to measure D3 pin voltage. When I push the button, D3 pin voltage changes from 0.x volt to 4.x volt. But digital…
Toni startup
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5
votes
1 answer

Replacement crystal on Uno for cold temperatures

I want to run an arduino out in the cold (-40), and use the serial communication - I believe that the crystal is the weakest link (the one for the serial chip) - however I don't see any drop-in (through-hole) replacement crystals that would work in…
user2813274
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5
votes
1 answer

Why can't most servos rotate more than around 180°

I was looking how a servomotor works. I realized that a standard servo can only turn up to 180°, but I didn't understand why. Is it because of the potentiometer?
roshan timsina
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4
votes
1 answer

How to burn the bootloader and upload sketches on ATmega328P U (specifically this model)?

Recently I started to learn embedded electronics and C/C++ and for a couple of days I tried and I am still trying to burn a new ATMega328P U bought from Aliexpress. From what I know new ATMega328P's come with bootloader included, but after I wired…
Vlad George
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4
votes
3 answers

Moving motion sensor?

Long story short, I'm trying to build some form of device that you can wear and it will detect when something moves behind you. I wanted to use PIR sensors for the motion detection, but I have no idea if they can detect objects if you're moving. Any…
Jack
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4
votes
4 answers

How exactly is voltage measured on an Arduino?

How do the analog pins on an Arduino measure voltage? Do they either measure current and calculate the voltage with Ohm's law? (If so, why can we only read voltage and not current directly?) Or do they compare the unknown input voltage with a known…
PenguinCake
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3
votes
3 answers

7-Segment Common Anode

I accidently bought a "Common Anode" 7-segment display instead of a "Common Cathode". I understand that the polarity of the leds within the display is 'reversed'. So instead of putting the common pin on GND I have to put it to 5v (with current…
aaa
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3
votes
1 answer

Common Ground Between Arduino and ESP32 - Can I Re-use the ESP32 GND Pin for a Potential Divider

I am trying to connect an ESP32 to an Arduino Mega via Serial Communication using the UART 2 ports on both microcontroller boards. There needs to be a common ground between the ESP32 and Arduino. Hence I have connected the ESP32 GND and Arduino GND…
timmy george
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3
votes
2 answers

How to turn LEDs based on voltage readings?

I am trying to turn LEDs in an LED bridge based on the voltage reading from a power source. when the Voltage is zero nothing is ON and then the LEDs gradually turn ON as increase the voltage connected to the Ao pin. ( I am using a pro trinket 3V 120…
Anwar Elhadad
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3
votes
0 answers

Sim800l doesn't respond to AT commands

My SIM800L doesn't respond to AT commands. The serial monitor is simply blank. And the led blinks every 3 seconds which means it is connected to a network I power it through an LM2596 buck down converter with 4.0 v (I've tried to power with voltages…
Ângela Sulissa
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3
votes
2 answers

AMIS30543 - Library code | Order of pinDirection and pinOut

This piece of code was taken from AMIS30543- Arduino library, void init(uint8_t slaveSelectPin) { ssPin = slaveSelectPin; digitalWrite(ssPin, HIGH); pinMode(ssPin, OUTPUT); } Facts I know digitalWrite - makes the pin to the…
Lawliet
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3
votes
2 answers

Sleep mode and watchdog at the same time

Suppose we want to save battery power, and we use sleep mode and also prevent the Arduino from hanging and use the watchdog timer. The problem is here that when the Arduino goes to sleep the watchdog timer never (or can't be) reset again because of…
sepehr
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