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Why is my Analog Input channel adding voltage to my signal?

EDIT: Here are the links to the sensor spec sheet (http://www.omega.com/temperature/pdf/HX71.pdf) and manual (http://www.omega.com/Manuals/manualpdf/M4543.pdf) for your reference. I'm using a relative humidity (RH) sensor with an Arduino Mega. The…
L. Paw
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Make Sure \n is the last character in serial string

I have an Arduino that I've put between a computer and an RS485 device. The job of the Arduino now is just to transmit data but will eventually do data logging and have a small user interface as time goes by. So far, this serial read code has worked…
ATE-ENGE
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Calculate absolute time based on cycles and RTC

I'm developing a low power data logging device. It samples sensors at the frequency of 20Hz, and also has a real time clock for absolute time (the logged time need to be exact down to ms). I think that querying time for every samples would be…
Dzung Nguyen
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Strange values from LSM303 Magnetometer

I am having problems with values i get from Pololu MinIMU-9 boards's magnetometer. I am using Arduino-micro and the arduino library from Pololu. The sensor on the board is 3 axis accelero- and magnetometer LSM303. The problem is - the highest value…
zidik
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Powering an USB to Serial from USB

I am creating a PCB which is a modification of the Arduino on a breadboard. I am intending to buy an USB to Serial breakout from Adafruit so that I can upload my sketches to the atmega 328 I'll be using. However, in order to reduce power…
francisaugusto
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4 answers

Issue with HC-SR505 sensor

I have been using a HC-SR501 PIR module with my Arduino Mega and it was tracking presence pretty well. Because of cost constraints, I decided to go with HC-SR505 sensor - bought a bunch of them. The performance is very bad. It almost seems like it…
Rahul
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Why digital pin not reading ON from push button switches connected to 5V and pull-down 10K resistor?

Here's my circuit: And the code: //pins const int control1 = 2; const int control2 = 3; const int enable = 9; const int pinDirection = 4; const int pinOnOff = 5; const int pot = A0; //states int stateOnOff = 0; int stateOnOffPrev = 0; int…
Roman
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3 answers

How to get number of available pins in code?

Different boards have different number of pins. Is there a way to know this number in code (at least digital and analog pins), or do I have to determine board type (like in this thread) and know the number of pins by myself? Reasoning for this is…
madneon
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Will an ATmega2560 board be faster than a Uno for hard real-time data logging?

I am designing a hard real-time data logger. The Uno is a bit marginal in processing speed. a) Would it be faster if I changed to an ATmega2560? b) On the datasheet, ATMEGA2560 has 135 instructions; it is 4 instructions more than the…
EEd
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Arduino Uno "WiFi Developer Edition" - How to disable WiFi?

I'm using Arduino Uno "Wifi Developer Edition". I made my Arduino to get connected with my local network based on http://www.arduino.org/learning/getting-started/getting-started-with-arduino-uno-wifi Now I would like to disable it and work with USB…
Trezor
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Pre-heat time required for MQ-5 gas sensor

The datasheet of MQ5 sensor says, it requires a pre-heat of 24 hours. Does this mean that it needs to be powered on for 24 hours consecutively before usage? Some other websites (e.g.…
Samdish Arora
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2 answers

Arduino Uno as USB to Serial converter (bypass 328p)

I'm trying out computer to computer serial communication using 2 Arduino Unos (both connected to different computers). Right now, I use the Software Serial library, which redirects data from the SoftwareSerial ports to the hardware Serial (over USB…
Carl
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How to send HTTP requests to specific port using Ciao?

I currently have a working REST client on my Arduino, but the requests always go to port 80. How do I make it send the request to a specific port? This is my current code: /* File: RestClient.ino This example makes an HTTP request after 10 seconds…
Mason
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Shortest time interval that Arduino Uno R3 can read

I am doing a light speed determination experimsmt. Lightspeed is around 3*10^8 m/s. For this, I need to measure time interval between 2 light sensors in nanoseconds, Somewhere about 50ns. Is this possible using the Uno R3? I know the clock is 16MHz…
Damodar Dahal
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Delay function without using a timer

Is there a delay function available that does not use millis() which itself makes use of a timer? Does not need to be hyper-exact.
Thomas S.
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