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1500 questions
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4 answers

What's the deal with Uno's pin 13 LED?

(I have a Sparkfun RedBoard, but this question seems to apply to R3 Unos and Uno-compatible boards.) As I was building the first circuit in my SIK guidebook (add a resistor, LED, hook it up and make it blink from code), I noticed a blue LED on the…
KatieK
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Use all pins As digital I/O

Increase the number of digital pins There are many post that explain how to use more than just the standard pins on the various arduinos but none of them explain the limitations and the proplems properly. Arduino Uno: 1.You can use the analog…
cocco
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2 answers

Put ATmega328 in very deep sleep and listen to serial?

I have investigated the sleeps options of the ATmega328, and read a few articles about it, and I would like to understand if there are more options. So I would like to get as low current as possible, so that anything less that 100uA would be good -…
Curnelious
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3 answers

Washable, Wearable Tech with Arduino

Question: How does one prepare clothing with embedded electronics for washing? Background: There are several Arduino boards/clones that are designed for "wearable tech." (For example, the Lilypad.) Wearable tech with LED light patterns,…
apnorton
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3 answers

Is it possible to find the time taken by millis?

The function millis would be running in the span of 100+ microseconds or less. Is there a reliable way to go about measuring the time taken by a single millis call? One approach that comes to mind is using micros, however, a call to micros will…
asheeshr
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13
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8 answers

Is it possible to upload a program from a tablet?

Is there any easy way to upload a program/sketch from an iPad or Android tablet without adding extra an shield (Bluetooth or Wi-Fi)? If not, can it be done using shield? Which shield is preferred? Also what are the IDE options available?
Rajendra
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2 answers

Changing the brightness on a Hitachi HD44780 LCD screen

I am finishing up a project- an LED game alarm clock. Seeing as this is a clock, I need to have a way to conserve power, which right now my Uno R3+ is eating up like a politician. My question is, how do I turn the screen off, or turn the back-light…
Mr. Floppy
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ATMega328P-PU and 328P-AU

im planing to make my very own arduino design based on the Arduino PRO mini. I picked this board instead of the UNO mostly because it's way more simpler compared with the UNO since the USB-to-Serial part is missing. As many of you know the MINI uses…
Meletis Flevarakis
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6 answers

Using String instead of C string, yet another attempt to touch a loaded issue

I've been reading a lot over the years why we should not use the notorious String class and how heap fragmentation is bad practice and not professional and we should never use it in our programs or we'll never enter the C hall of fame and get to be…
Nino
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Arduino as ISP without a computer

Has anyone seen or know of a method of preloading (using a computer or whatever) a firmware as data onto one arduino set up to operate as an isp and then using that arduino plug the isp interface into another and upload the firmware. To be clear -…
m3z
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4 answers

Why is it considered bad practice to use the 'new' keyword in Arduino?

I previously asked this question: Is it required to delete variables before going to sleep? On that question, @Delta_G posted this comment: ... Really on a microcontroller I would create the object in a smaller scope and try to do everything in my…
Tono Nam
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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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Why can I not use pointers instead of array with PROGMEM?

I'm currently changing some libraries to use flash instead of RAM for string storage so that I do not run out of SRAM on a project. Some strings in the library are declared in this manner: const char *testStringA = "ABC"; This is different to how I…
Cybergibbons
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Does the ESP8266 somehow remember wifi access data?

Today I did some tinkering with an ESP8266, trying out OTA and writing a webserver. To find an error, I reduced the sketch to just the following lines: #include ESP8266WebServer server(80); void setup() { …
Geier
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2 answers

How do I figure out if my board is approaching end of life?

I have a uno that I have been using for 3 years now. I will be using it again in a rather critical project in which failure on the part of the board could be rather expensive and dangerous. So, I would like to be sure that the board is not…
asheeshr
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