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1500 questions
13
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3 answers

Arduino Mega timeout communication with programmer error

I have an Arduino Mega 2560 and it was working fine until about lunch time when I started getting this error: avrdude: stk500v2_ReceiveMessage(): timeout avrdude: stk500v2_getsync(): timeout communicating with programmer I know it isn't the code…
bladepanthera
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1 answer

Cannot program two arduinos at the same time because they both use the same COM port

I am not able to program my second arduino because they both use the same com port. In other words this picture says it all: In order to upload my sketch I have to disconnect one arduino. How can I tell windows to use a different COM port? It will…
Tono Nam
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13
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6 answers

Why do you need a second resistor when using a photoresistor/LDR?

A photoresistor is already a resistor and will limit the voltage in the circuit. Why can't this be connected to a pin and measured? Why is a second resistor needed to connect the photoresistor to ground?
Jason
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13
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1 answer

_delay_ms() is much slower than expected (by a factor of 6) on TinyAVR 0/1 (ATTiny1604)

I designed a custom AVR development board using the Atmel ATTiny1604 microcontroller. It belongs to the new Tiny-0 family, due to its recentness, some required changes to relevant toolchains have yet to be included into the stable version (I prefer…
比尔盖子
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13
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5 answers

My DS18B20 is reading high. How can I get it to return the correct temperature?

I am working on a heating control system for my home, but having problems with the temperature sensor reading higher than I expect. I have a 5V Arduino Mini Pro clone hooked up to a relay module, an HD47780 display and a Tiny RTC module, with a…
Mark Booth
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13
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3 answers

What alternatives are there to the Optiboot bootloader?

Nearly all modern Arduino boards use the Optiboot bootloader. Compared to the ATmegaboot used before, this is smaller in flash terms (by about 1.5KB) and faster in upload speed (115.2k vs 57.6k) and starts your sketch quicker (the delay whilst…
Cybergibbons
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13
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6 answers

Addressable RGB strip works fine individually but cannot set all LEDs to full white

I have a 5 meter strip of 12V digital RGB LEDs. The chip is WS2811 (see photo of IC). There are 50 addresses on the strip. Using the FastLED library, I am able to run the "FirstLight" example that chases full white with a single address at a time,…
Bort
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13
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4 answers

Getting a truly random number in Arduino

What is the best method to get a truly (as opposed to pseudo) random number in Arduino, or at least the best possible approximation? From my understanding, the function randomSeed(analogRead(x)) it's not random enough. If possible the method should…
Rexcirus
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13
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4 answers

How to show the º character in a LCD?

I have a 16x2 LCD and I want to show a temperature: 23 ºC. But the º symbol is not properly shown. It shows a strange character instead of the º symbol .
Roby Sottini
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13
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3 answers

Hiding WLAN password when pushing to GitHub

I have started to use GitHub to store Arduino code. However some of my code uses the SSID and password for my WLAN which I don’t want published. A common way of handling this in non-embedded programming is to use a configuration file, but that…
Andrew Doble
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4 answers

Is setup and loop provided for convenience?

Arduino sketches usually feature a setup and loop function. Are these functions only provided for convenience or do they actually have special purposes? (e.g.: are some operations disallowed or allowed in setup and loop) Are these two pieces of code…
Sebazzz
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13
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2 answers

How to manage dependencies?

I want to include a dependency like Logging. On its page it says: Download zip file Put the Logging folder in "libraries\". I don't want to believe (with a Maven mindset) that this is the way we manage dependencies in Arduino projects. That means,…
Markus Malkusch
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13
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4 answers

Does ADC conversion to a voltage rely on the actual value of the +5 V pin?

Questions: Does the conversion of the ADC count to voltage depend on the actual voltage of the +5 V pin? If yes, what is the accepted method of getting that voltage from the board? Background/Detail: I have a circuit in which I have an Arduino…
Caribou
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13
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7 answers

Where can I find a central repository of all available Arduino libraries?

Currently; when I start a new Arduino project with some new hardware, the first thing I do is to look for 3rd-party libraries that bring Arduino support for this hardware. The first places I look are: The Arduino Playground GitHub Google Generally…
jfpoilpret
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13
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6 answers

How to output a true analog voltage at output pin

Regarding my program, it is a program that does some calculations and then outputs a voltage based on the result using analogWrite function. However my problem is that I had done my programming based on a misconception that analogWrite function via…
bytk
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