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1500 questions
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2 answers

RFID/NFC (13.56 MHz), is it possible to send raw bytes and receive response?

I'm trying to implement a card reader (i.e. credit cards) for shopping purposes, and AFAIK those cards are ISO 14443-A compliant (Mifare Classic 1K). I already made an Android app that can send custom APDU to read specific sectors by using raw…
TheAverageGuy
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2 answers

Servo won't stop rotating

I have an Arduino Uno R3 board and after some time not in use it seems to have corrupted. My code is below, basically I want to rotate a servo 90 degrees every 12 hours but as soon as I plug it in the servo starts rotating non-stop. Have tried…
Stedy
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How to read pinMode for digital pin?

Is there a way for me to read the pin mode for one of the digital pins on Arduino? In other words, can I determine whether a pin's been set to an input or output?
John
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9
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1 answer

Is there any way to run binary code from RAM?

I am looking for an inexpensive single board computer that I could program in assembly language, using limited facilities to load the object code from a PC and simple I/O peripherals. Ideally I would like to be able to write in a reasonable time all…
pierre
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9
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7 answers

How to remember variable values after rebooting an Arduino Uno R3 board?

Is there any way to store the values of necessary variables somewhere (may be in a file that gets updated by the program at various events), which can be read back when program starts after rebooting the Arduino board? I am trying to control my AC…
Samik Chattopadhyay
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9
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2 answers

Arduino at 20 MHz?

I wonder why Arduino doesn't run at 20 MHz, the frequency the AVR is specified for. Now, running at 16 MHz, we're wasting 20% performance for nothing. I don't think there are any implications when you replace the 16 MHz resonator with a 20 MHz…
Joris Groosman
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9
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1 answer

Overview of compiled code size

When I compile my code, the Arduino IDE returns the binary sketch size in byte. Is there a good way to find out (approximately) what function or what part of my code takes up how much memory in flash, so that I get a feeling what feature takes most…
fuenfundachtzig
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9
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2 answers

How do I use Arduino and node.js?

I am new to Arduino, however I have experience in web development, lately I have been using, meteor js and the mean stack for different projects. However, I am open to trying any language for development. What I am trying to do is build a simple…
Anders Kitson
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9
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1 answer

Problem programming Mini Pro via Arduino as ISP

I just picked up a pair of Arduino Mini Pro 5v clone boards (Inland, sold at Microcenter, currently $4 USD) and I wanted to use my Uno as an ISP like I've done with ATmega328 and ATtiny85 chips before. I've programmed the Uno with the instructions…
Dennis Munsie
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Will the arduino power autoselection logic short the regulated 5V and the USB 5V?

From the reference design of the Arduino UNO r3, I find that USBVCC will be connected to +5V via mosfet T1 if Vin is below 6.6V. Doesn't this short the two sources if Vin is just below 6.6V? The datasheet for regulator U1 (NCP1117) mentions input…
Trygve Flathen
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8
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3 answers

What is the rise time of an output pin of atmega328 changing its state?

I've already searched a lot and didn't found the answer. Also, I don't have an o'scope. Anyone can help me?
Pedro Quadros
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8
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3 answers

Serial Print, String And Variable On Same Line

How can I print to the serial monitor a string or just single character followed by a variable like "L 55"
Root0x
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8
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1 answer

7 segment LEDs on wood face

I'm not sure this is right place for this question, but does anyone have any idea how a 7 segment display is projected or embedded in wood for products like this? Full product info at…
devth
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8
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1 answer

Arduino and ESP8266 Web server

First things first, if there was an ESP8266 StackExchange, I would post this there. I am setting up a web server that will programmaticly be controlled from an external Python script, and I am currently able to send this server data using this…
Butters
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8
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2 answers

Is there a way to make wiring a bare microprocessor to a shield easier?

I currently do most of my AVR work on breadboards, but the large variety of Arduino shields and code out there makes me wonder if I'm not beating my head against the wall sometimes, and looking up port to pin mappings both wastes time and slows me…
Ignacio Vazquez-Abrams
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