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1500 questions
4
votes
3 answers
The exact time for functions or CPU cycles for any function
I'm trying to read input data from the parallel port of a PC and send it to another device. For this purpose the input data is saved, when it's available and is sent if a flag is set.
The whole procedure should be done in less than 10 ms. I need to…
Mehran
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4
votes
3 answers
Error: 'SofwareSerial' does not name a type
I have trouble compiling this sketch. The error I get is
'SoftwareSerial' does not name a type
Any ideas how could I fix it?
#include SoftwareSerial.h
SoftwareSerial mySerial(10, 11); // RX, TX
void setup()
{
// Open serial communications and…
alkopop79
- 145
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4
votes
4 answers
Importance of resistor
I'm new to Arduino and also new to electronics. I'm following the tutorial here. I'm not understanding the importance of the resistor in this schematic diagram. Can someone please help me on this?
Noor
- 143
- 5
4
votes
4 answers
Why does opening the Tools menu take so long?
Every time I open the Tools menu, the IDE freezes for a few seconds. Why is that? It happens on both of my computers, and nothing I do makes a difference in how long it takes. I've tried restarting the IDE, unplugging my Uno, and many other things,…
The Guy with The Hat
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4
votes
1 answer
How many Infrared sensor modules can be added to a single Arduino (eg;Uno)
I am looking to add block detection to my model railroad. I need approx. 40 infrared sensors to power 40 LED's on my control panel. No signals or other logic required yet, just the LED indications -LED- on=occupied off=vacant.
How many Uno boards…
RioGrande89
- 41
- 3
4
votes
3 answers
What happens if I don't use a relay for 5V pump
I am trying to build an automatic watering system by following some examples. However, I don't have all the components for the entire system, therefore I have built it in Fritzing using only the components that I have (see scheme below):
I didn't…
Physther
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4
votes
2 answers
just a silly doubt about glowing an LED
what will happen if i insert the anode of a LED to pin 12 and cathode of the LED to pin 11 and set pin 12 to high and pin 11 to low,will the led glow??
4
votes
2 answers
ESP8266 not working properly
It's the first time I use an ESP8266 and I didn't manage to get a proper response in the Arduino serial monitor. I only see weird characters, when I move the 3.3V wire.
You can see the connections in the following picture:
The code I run is the…
Alberto Carmona
- 141
- 3
4
votes
3 answers
Installing Arduino IDE on Linux
I downloaded arduino-1.8.4-linux32.tar.xz and ran install.sh as outlined (the very sketchy instructions) in https://www.arduino.cc/en/Guide/Linux
This seemed to work OK, so I removed 354M of what I thought was the installer, only to discover that I…
Milliways
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4
votes
1 answer
Arduino 101 accelerometer drift or calculation error?
I want to calculate the displacement of the Arduino 101 board compared to the starting point (only in the x direction so far).
In below data I'm swinging the board multiple times in circles around my laptop and then putting it back at the origin a…
Henrik Bohman
- 51
- 3
4
votes
3 answers
upload.tool not used in custom boards.txt?
I've created a custom board in boards.txt and changed the upload.tool to a nonsense value, and yet when I do an upload the IDE still calls avrdude.
For example, In boards.txt I've changed the…
bigjosh
- 1,593
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4
votes
2 answers
SIM800L and Arduino Sleep - getting whimsy Serial output after 5 calls
i'm working on project where i'm trying to achieve that arduino parse caller ID so i can use it later to send SMS with sensor reading data.
Somehow i made that code (with much googling) and it works great... But when i include arduino sleep part, it…
user3613833
- 41
- 3
4
votes
3 answers
How to detect if LED is switched on in external circuit using Arduino NANO?
I want to detect when an LED is powered on using an Arduino NANO. The LED is part of an external circuit. The LED uses about 1.8V. Would the circuit below allow me to detect when the LED is switched on? Is this the correct method of doing it? (The…
user37547
4
votes
3 answers
Arduino Uno - relay with separate power
i want to operate a relay with an ARDUINO UNO, but i want to use a separate power supply for the relay. Ive seen relays with VCC and jVCC (dont know what that is), but mine only has this pins: GND, IN1, IN2, VCC.
how should i connect it to the…
randall
- 41
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4
votes
1 answer
Selling a product using Arduino microcontroller or bootloader
I was wondering if I am legally allowed to sell an Arduino based product. I also want to know if it is easy for people to retrieve code from an Arduino based circuit (reverse engineer it) or upload code from Arduino microcontrollers.
If I'm posting…
Doge Skywalker
- 41
- 2