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1500 questions
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2 answers

What is the difference between the revisions of the Arduino Uno board?

There are three different revisions of the Arduino Uno. What changed in each revision?
tstew
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6 answers

Is there a way to play sounds from an Arduino without using a sound shield?

I would like to play a wav file (spoken words) from my Arduino. I do not want to add a sound shield. Is there a way to play a sound through an output pin? The quality does not have to be great.
Hoytman
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How to avoid that my arduino clicks eternally?

I have accidentally implemented a program that imitates the click of the mouse. The problem is that now I can´t delete the program because each time that I connect the USB, the computer starts clicking everything and it is not possible to upload a…
Zero point
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5 answers

What's the difference/relationship between Arduino and AVR?

I'd always thought Arduino was a microcontroller platform but the actual microcontroller is an AVR chip made by Atmel, or something like that made by someone else, based on a RISC ISA, and Arduino is usually used to refer to the whole circuit board…
user3383182
13
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3 answers

What is the point of D0-D3 on LCD?

The Arduino LiquidCrystal library has 4 constructors with different arguments: LiquidCrystal(rs, enable, d4, d5, d6, d7) LiquidCrystal(rs, rw, enable, d4, d5, d6, d7) LiquidCrystal(rs, enable, d0, d1, d2, d3, d4, d5, d6, d7) LiquidCrystal(rs, rw,…
Friend of Kim
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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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5 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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_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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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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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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4 answers

Some Arduino components seem ridiculously cheap

My project is an Arduino-based device, packed into a box. It will need to use Speed, Latitude, Longitude and Altitude data to log hills it detects on to an SD. On the press of a button, it will need to upload the hill data to the server via Wi-Fi. I…
R Harrington
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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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10 answers

Sensor for underground water tank level

In a similar way to the question "best way to determine if a 5 gallon water jug is getting empty", I'm looking for a way to measure water in a container. This is so it can be connected to an Arduino for logging and reporting. But it's a very…
Rob Hoare
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1 answer

Convert int to char[]

I'm looking to convert an int value to a char array. currently I've found the following will return [number] int num = [number] str = String(num); str.toCharArray(cstr,16); Serial.println(cstr); However, per Majenko's The Evils of Arduino Strings I…
ATE-ENGE
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Assembly on the Arduino: IO registers

Question: What registers do I use to access the IO on the Arduino Uno when I am using assembly for programming? Background: I was interested in practicing my assembly language skills on the Arduino (I thought it would be easier to turn LEDs on/off…
apnorton
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