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1500 questions
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2 answers

Arduino potentiometer example: what limits the current?

I have a question regarding potentiometer example: https://www.arduino.cc/en/Tutorial/AnalogReadSerial If I turn the potentiometer to the marginal position and have 5V at A0 (and almost zero resistance at the pot), what limits the current flowing…
Denis Kulagin
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Does a graphical driver chip exist for this project?

I need some expert advice. I'm using an Arduino Leonardo, which I have got working with a Nokia 3310 monochrome screen. I wrote some code to draw any graphics to the screen. What I want to know is, can I buy a chip from somewhere that will offload…
Karlie Kloss
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Why does an RGB LED between VCC and PWM work?

I'm an Arduino beginner and I recently bought a cheap starter kit on eBay. One of the lessons in the starter kit is an RGB LED controlled by 3 PWM output pins. However, the arrangement of the connections seems a bit funny to me: To my surprise, it…
NobRuked
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Why is my Adafruit motor shield not spinning my motors?

I'm using the Adafruit Motor Shield v2.3. I'm powering the Arduino with a USB cable and I'm powering the motor shield with a 9 volt battery. I removed the vin pin, and I'm using this tutorial/code to make the DC motor spin. I've tried 3 different…
Pikamander2
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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 Arduino continuously reads out those 64 digital…
Edo Paulus
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5
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3 answers

How to read bitmap image on Arduino

I want to convert a bitmap into binary array. My bitmap image is 272*208 pixel monochromatic 1bpp image. I'm confused when the width I get from my image is 16 instead of 272, the height is corrected. And when I skip the bitmap header to get bitmap…
Seawish
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Optocouplers for Arduino DCC decoder - Explain?

I am trying to make an Arduino circuit as outlined here. This is for connecting an Arduino input to a DCC system. DCC is a command control system for model railways that uses the same two wires for power and data (there's a wikipedia article that…
K4KFH
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4 answers

Briefly "wake up" Arduino in response to an event

I want to connect a device to a door handle, so whenever someone opens the door I'll be able to send a message via my arduino that is connected to a WIFI shield. I have a simple orientation sensor, so I know when the handle is being pushed. The…
Avenger
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Can an Arduino act as a GATT Server (Bluetooth LE)

I know it's pretty standard to set up an Arduino system as a BLE client, and use something like an app running on a smartphone as the GATT server, which receives the data and does something with it. In my scenario I have a BLE sensor that is not…
Tom Auger
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Trouble when avoiding delays

I am new to Arduino and I am learning how to avoid using delay. I have written some code to move my servo by 20° using delays, but can only move the servo once with my current code. In setup(), I assign the servo 150. The next value the servo…
Corey
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Can I use a GPS from old Garmin with an Arduino?

I'm working on an Arduino project, and I'd like to add GPS functionality. I could buy a GPS module, but those are expensive. I had an old Garmin Forerunner 305 lying around, so I took it apart and took a peek inside. There are two PCBs - one…
geckods
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HardwareSerial - check for overflow

The SoftwareSerial library has a built-in Overflow function, but the Serial library does not. Is there a simple way to check for a data buffer overflow on a hardware serial port?
Joel M.
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1 answer

Basic C++ programming, how to pass constructor argument into class?

I'm having some programming problems. So here's what's happening: In my .ino file, I have a tft variable which holds the connection to a LCD. I want to make a class which can either automatically access that tft class contained in the .ino, or pass…
vxcheese
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3.95 MCU Friend Arduino TFT LCD flickering

I got the 3.95" LCD from aliexpress which uses IL9488. I used the MCUFRIEND_kbv library. I am using an Arduino Mega as I need other GPIO to be used for other purposes. I can't use the Uno because of this limitation. I have other modules like the…
rahulmr
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Arduino DC motor causes disturbance. What can cause it?

I tried to fix this problem the whole weekend but, after no success I decided to post it here. I would really appreciate any help. The problem The Wi-Fi module activates the DC motor and lets it run for 3 seconds, but when the DC motor stops after…
Vince verhoeven
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