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RTC resets when power is off

I have a few RTC modules with a batteries. All of them have this same issue with my project. They work fine when connected via USB. But if I disconnect the power then reconnect they reset to Jan 1 2000. I've read several posts about similar…
futurebird
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Two sensors on one input

I got this question from my teacher the other day and I can't figure it out: If you have two sensors from two different outputs but want them to go into one input, what do you need, and how can you read the input? In short, the project includes…
NicklasF
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Arduino Uno not able to handle 2-dimensional array

Now the code I'm writing in Arduino (Using Arduino) uses multiple 2-dimensional arrays. Now when I print some thing using the Serial Monitor it prints it correctly but when I declare and initialize the 2-dimentional array it won't print…
George J. Adams
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How to power an Arduino Uno with 3 1.5V batteries?

I have an Arduino Uno (a SainSmart model, actually). I intend to power it with three 1.5V batteries. I measured them and they yield 4.67V in total. The Arduino requires 5V. The question is, if the arduino will work this way. I'm not powering…
bytecode77
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Is the Sparkfun RedBoard pre-loaded with a blink sketch?

As soon as I plugged my brand new RedBoard (Sparkfun's Uno) into my computer, I saw the onboard LED (for pin 13) blink on and off every 1 second. This was before I even sent the first demo sketch to blink the LED. After I uploaded a sketch to change…
KatieK
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Can I speed up the Leonardo bootloader?

Inspired by an example question before beta, can I make the Leonardo bootloader take less that 8 seconds to run? It is very slow and I want to speed it up somehow.
TheDoctor
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How to receive data from my server database to a variable in my Arduino?

I am learning to work with the client - server communication. I am able to communicate with my server and able to store values in the table. But I want to receive one of the specific data from the database. Here I want to get the 'abc' value from…
Manihatty
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Passing class member function as argument

I need to pass a class member function to server.on, unfortunately i get an error. error: no matching function for call to 'ESP8266WebServer::on I have done some searching but could not understand anything I found. No simple explanation. This…
Molda
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how does serial port communication work under the hood?

im just looking for how to send/ write date to pc over serial port from arduino..vice versa. I have few Question to ask after taking so much time and couldn't figure it out myself. I hope you guys can guid me please. First, i found i can use…
denis_choe
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IR frequency difference

I want to create a device that interfaces with the Light Strike Lasertag system using an Arduino Leonardo. The Light Strike system uses not laser but regular infrared signals. According to a site that I found…
Dakkaron
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Arduino Due and BNO055 address in i2c mode

I have a project where I need to have several IMUs, the BNO055 shuttle board (I explained my project here), I manage to get the Euler angles from one BNO055 sensor, which have the address 0x29, because I linked the I2C_MODE_ADR_SEL to a HIGH level.…
BunkSB
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Use LED on pin 13 again after using the SD library

The question in short: On an Arduino UNO or Nano using the SD library, is it somehow possible to use the LED on pin 13 (or any other pin that is used by the library) again after finishing all SD operations? Detailed explanation: In my sketch, during…
Johannes Maibaum
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Is the SIM900 3G? Or is the SIM900A able to connect to 3G?

I would like to state that I am not familiar with the whole cellular connection thing. But I was wondering if the SIM900/or/SIM900A is 3G and will work with PTel Mobile. I need this Arduino to be able to travel and needs to connect to every PTel's…
Marcello B.
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How to display a number using SevSeg library on 4 digit 7 segment LED display

I am getting error with this. It is displaying those segments which are not to be displayed, i.e., 3.141 is dark and other segments are red. #include "SevSeg.h" SevSeg sevseg; //Initiate a seven segment controller object void setup() { byte…
JSO
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4 answers

Read OUTPUT pin value in Arduino Due

I am trying to read the value of an output pin. online forums say that digitalRead(pinNum); should work, but that is not the case here. digitalRead always returns 0 (LOW). This is the code: int pin = 22; // or 13, or 3 ... void setup() { …
Makan
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