Conneting Adafruit m0 with dht22 - arduino

I am new to low-level programming, and attempting to connect a DHT22 sensor onto my Adafruit M0 Lora for temperature readings. So far I only retrieve NaNs.
The connections I have set up are identical with this sketch, aside from using pin 13 as opposed to pin 2 for sensor input/output. I am aware of the sketch being made for a different feather board, although the logic should still remain the same from what I can understand.
I am making use of Adafruit's DHT library
#include <Adafruit_Sensor.h>
#include <DHT.h>
#include <DHT_U.h>
// pin connected to DH22 data line
#define DATA_PIN 13
DHT_Unified dht(DATA_PIN, DHT22);
void setup() {
// start the serial connection
Serial.begin(9600);
// wait for serial monitor to open
while(! Serial);
// initialize dht22
dht.begin();
// connect to io.adafruit.com
Serial.print("Connecting to Adafruit IO");
// we are connected
Serial.println();
}
void loop() {
sensors_event_t event;
dht.temperature().getEvent(&event);
float celsius = event.temperature;
float fahrenheit = (celsius * 1.8) + 32;
Serial.print("celsius: ");
Serial.print(celsius);
Serial.println("C");
Serial.print("fahrenheit: ");
Serial.print(fahrenheit);
Serial.println("F");
// save fahrenheit (or celsius) to Adafruit IO
dht.humidity().getEvent(&event);
Serial.print("humidity: ");
Serial.print(event.relative_humidity);
Serial.println("%");
delay(5000);
}
Would anyone be able to help point of what I am doing incorrectly? I tried at other bauds than 9600, as well as changing the programmable pin. Any help at all would be greatly appreciated.

I don't think it's a code problem. Pin 13 is special. Choose a different pin.
Specifically:
NOTE: Digital pin 13 is harder to use as a digital input than the other digital pins because it has an LED and resistor attached to it that's soldered to the board on most boards. If you enable its internal 20k pull-up resistor, it will hang at around 1.7V instead of the expected 5V because the onboard LED and series resistor pull the voltage level down, meaning it always returns LOW. If you must use pin 13 as a digital input, set its pinMode() to INPUT and use an external pull down resistor.
From Arduino documentation.

Related

Particle Photon, controlling a PCF8574 via I2C- works on Arduino

I'm trying to read and control some buttons and LEDs on a Bang & Olufsen infrared eye. It uses a pcf8574 microcontroller to control 2 LEDs and 4 buttons. First of all I just want to get the LEDs to blink. I have successfully done that with an Arduino Uno.
But I want to use it with an Particle Photon so I can connected to the internet. Here I have the code that worked on the Arduino:
#include <Wire.h>
#define beolink (B0100000)
void setup() {
Wire.begin();
}
void loop() {
Wire.beginTransmission(beolink);
Wire.write(0b11111111);
Wire.endTransmission();
delay(1000);
Wire.beginTransmission(beolink);
Wire.write(0b00111111);
Wire.endTransmission();
delay(1000);
}
I have no errors on the Particle Photon. I have also tried switching cables and tried 5v instead of the 3.3v. I have connected the pins on the Particle Photon to the same as on the Arduino [SCL(D1) & SDA(D0)].
Thanks to this guy: https://community.particle.io/u/scruffr/summary
It now works. It was not a problem with the code. Apparently you need 2 pull-up resistors on the I2C pins on a Particle Photon. thank you

Using Serial.print and digitalWrite in Same Arduino Script

I am using an Arduino Uno and Windows 7. My goal is to have an LED light that blinks, and when it blinks, it prints out "Blink" to the serial monitor.
When I run the code below, I am able to print out "Blink" to the serial monitor every 2 seconds, however, the light remains constantly on. When I remove the line
Serial.begin(9600);
the lights will blink, but nothing will print. The code I am running is as follows:
int LED3 = 0;
void setup() {
// When I comment out the line below, the lights flash as intended, but
// nothing prints. When I have the line below not commented out,
// printing works, but the lights are always on (ie do not blink).
Serial.begin(9600); // This is the line in question.
pinMode (LED3, OUTPUT);
}
void loop() {
Serial.println("Blink");
digitalWrite (LED3, HIGH);
delay(1000);
digitalWrite (LED3, LOW);
delay(1000);
}
I am unclear on what causes this behavior and would appreciate an explanation of why this occurs and how to avoid this problem. Thank you!
what causes this behavior ?
Pins 0 and 1 are used for serial communications. It's really not possible to use pins 0 and 1 for external circuitry and still be able to utilize serial communications or to upload new sketches to the board.
From the Arduino Serial reference documentation:
Serial is used for communication between the Arduino board and a computer or other devices. All Arduino boards have at least one serial port (also known as a UART or USART): Serial. It communicates on digital pins 0 (RX) and 1 (TX) as well as with the computer via USB. Thus, if you use them in functions in your sketch, you cannot also use pins 0 and 1 for digital input or output.
Just think it this way how can a pin act serial and digital simultaneously ? Yeah that's what you are trying to do !! . You set pin to serial at a baud rate and then you used it for making LED blink.
So, when you do serial.begin(9600); it Sets the data rate in bits per second (baud) for serial data transmission to 9600.Thus you used serial pins in this function, after that you cannot use pins 0 and 1 for digital input or output ( like an LED ). when you comment serial.begin(9600); your pins are free to use and thus you obtain the output.
how to avoid this problem ?
Change the LED from pin 0 to digital pins.
The following code will obtain the result that you expect (I used pin 7 in it) :
int LED3 = 7; //I have changed pin to 7 ( you can use any except 0 and 1 )
void setup() {
// When I comment out the line below, the lights flash as intended, but
// nothing prints. When I have the line below not commented out,
// printing works, but the lights are always on (ie do not blink).
Serial.begin(9600); // This is the line in question.
pinMode (LED3, OUTPUT);
}
void loop() {
Serial.println("Blink");
digitalWrite (LED3, HIGH);
delay(1000);
digitalWrite (LED3, LOW);
delay(1000);
}
The Arduino is using pins 0 and 1 for serial communications.
Pin 0 is RX and 1 is TX, so when you are trying to flash the LED also connected to pin 0, the two start stomping all over each other.
Try to move the LED to a different pin and update your sketch to match, and it should start working.
This page contains information on the Arduino serial connection: https://www.arduino.cc/en/Reference/Serial
Happy hacking

Arduino Uno DC Motor not working with simple test. Can not get Arduino to spin the motor

I am using the V2.3 motorsheild on the arduino uno r3.
I no almost nothing about ardunio excpet from what ive read about the past week.
I have been trying to simply turn the motor with the code below and it wont work. I have the arduino plugged into my computer and 12v going to the blue power box thing.
I am using this motor https://www.servocity.com/html/900_rpm_micro_gearmotorblocks.html#.VyELIFaDFBc
I cannot get the dang thing to spin, motor works fine if i wire it straight to the 5v/grnd but not when its in the M1 connection
wiring: https://i.groupme.com/747x1328.png.54a01e30433241d4a99905bd0e8ede2b let meknow if this link doesnt work
Heres an Imgur link for the wiring http://imgur.com/J92ewnu
#include
AF_DCMotor motor(1);
void setup() {
Serial.begin(9600); // set up Serial library at 9600 bps
Serial.println("Motor test!");
// turn on motor
motor.setSpeed(200);
motor.run(RELEASE);
}
void loop() {
uint8_t i;
Serial.print("tick");
motor.run(FORWARD);
for (i=0; i<255; i++) {
motor.setSpeed(i);
delay(10);
}
for (i=255; i!=0; i--) {
motor.setSpeed(i);
delay(10);
}
Serial.print("tock");
motor.run(BACKWARD);
for (i=0; i<255; i++) {
motor.setSpeed(i);
delay(10);
}
for (i=255; i!=0; i--) {
motor.setSpeed(i);
delay(10);
}
Serial.print("tech");
motor.run(RELEASE);
delay(1000);
}
I am not expert in current particular shield and its library. But what i see when first time look at your sketch and motor connection image is that you are trying to run dc motor at a certain speed with commands, which seems to be for servo or stepper motors.
You should know that running DC motor at some speed is possible if you have speed calculation based on its current and voltage or when a speed sensor is located at motor's shaft. This motor doesn't have the sensor (i know it for sure, because used same in my projects) and i think the shield can't calculate speed. What you can is only switch it on and off and maybe change its direction.
So, first of all you should look (and use) at the library for such functions.
Looking for what the function you called "AF_DCMotor" does I see how you were confused. There is also this product, which is another adafruit motor sheild.
But it's actually a very different motor driver. Both shields have a power stage which takes pulses and amplifies them to drive a motor. The V2 apparently has a chip which generates these pulses, and you send it serial data to command it using I2C. The V1 just gets these pulses directly from the Arduino.
For yours, a V2 motor shield, try the guide Adafruit provides.
Here's the link - Adafruit Motor Sheild V2 DC motor control
And here's the code
#include <Wire.h>
#include <Adafruit_MotorShield.h>
#include "utility/Adafruit_MS_PWMServoDriver.h"
Adafruit_MotorShield AFMS = Adafruit_MotorShield();
Adafruit_DCMotor *myMotor = AFMS.getMotor(1);
AFMS.begin();
myMotor->setSpeed(100);
myMotor->run(FORWARD);
It mentions the use of I2C on the introductory page
Instead of using a latch and the Arduino's PWM pins, we have a fully-dedicated PWM driver chip onboard. This chip handles all the motor and speed controls over I2C
That's why it includes the Wire library. You could make your own code to run this, but it would have to use I2C to send commands to the PWM driver chip they are using.

Arduino UNO + Ethernet Shield + Ultrasonic Sensor = Fail

With my Arduino Uno I measure the distance using HC-SR04 ultrasonic sensor with no problems at all using the wiring below.
When I attach ethernet shield, my ultrasonic sensor does not measure distance any more, it constantly says 0cm no matter what. I have tried different digital pin pairs such as 5-7, 6-8, 5-9, 3-5, 2-8 but no luck.
I suspect that HC-SR04 is not compatible with my Ethernet shield but I haven't seen such warning anywhere on the net.
There are no components attached to arduino besides ethernet shield and the ultrasonic sensor itself.
There is no SD Card in SD Card slot.
My ethernet shield works fine while running a web server or web client script.
Digital pins of ethernet shield works fine with all other components such as temperature sensor, motion sensor etc.
Here is the ethernet shield I have;
http://www.ezshopfun.com/product_info.php?products_id=169
Here is my actual circuit;
http://s7.postimg.org/vyi2z36qz/20140826_001130.jpg
http://s7.postimg.org/6eb7ewvzf/20140826_001150.jpg
http://s7.postimg.org/6psnrocff/20140826_001156.jpg
http://s7.postimg.org/y6ro2ooh7/20140826_001229.jpg
http://s7.postimg.org/71a44fsvf/20140826_001247.jpg
Here is my code;
#define trigPin 6
#define echoPin 7
void setup() {
Serial.begin(9600);
pinMode(trigPin, OUTPUT);
pinMode(echoPin, INPUT);
}
void loop() {
int duration, distance;
digitalWrite(trigPin, HIGH);
delayMicroseconds(1000);
digitalWrite(trigPin, LOW);
duration = pulseIn(echoPin, HIGH) / 2;
distance = duration / 29.1;
Serial.print(distance);
Serial.println(" cm");
delay(500);
}
Today I bought a multimeter and tested my circuit. Here are the results;
When my circuit directly attached to Arduino itself;
4.80V & 5.7mA
When my circuit attached to ethernet shield;
3.06V & 3.8mA
I think the problem is that 3.06V is not enough for my HC-SR04 to operate.
Yeah based on this photo
you're not grounding your sensor. You have two power supplies going into it. This, needless to say, is bad for a number of reasons. First and foremost because it wont work ungrounded lol
As others have said, it looks like the main issue is that you need this connected to 5V and check your wiring generally.
However, there is another potential issue:
digitalWrite(trigPin, HIGH);
delayMicroseconds(1000);
digitalWrite(trigPin, LOW);
You only need to set the trigger pin high for 10 microseconds, not 1000 microseconds. I don't know if this is an issue or not but there is no need to wait this long. You could potentially be missing some or all of the incoming pulse by waiting that long.
You might want to checkout out some HC-SR04 tutorials too, like this one:
http://superawesomerobots.com/tutorials/hc-sr04-tutorial-for-arduino/
Hope that helps.
I had a similar problem with a wifi shield + ultrasonic sensor. I found switching from pins 13(trig) and 11(echo) to 8(trig) and 3(echo) fixed it.
See here: http://forum.arduino.cc/index.php?topic=201827.0

Reading sensor input with Pic32 and MPIDE

So I currently have a pic32 arduino. I'm pretty new to this stuff, so any tips would be appreciated.
I have a sensor that has 3 pins, 5VDC, ground, and sensor output. I connected the sensor output and ground header to the two pin slots at PORT0.
For some reason, the program always reads that the sensor is HIGH, even if the sensor is not connected.
If I connect the output to a breadboard with an LED, I can see the LED toggle on and off.
Here is my code:
const int sensor = 0; //sensor port
int sensorState = LOW;
void setup(){
pinMode(ledPin, OUTPUT);
pinMode(piezo, OUTPUT);
pinMode(sensor, INPUT);
Serial.begin(9600);
}
void loop(){
sensorState = digitalRead(sensor);
if(sensorState == HIGH)
alarm();
digitalWrite(ledPin, sensorState);
Serial.println(sensorState);
}
You may have the internal pull-up resistor enabled, so when nothing is connected, it will read high.
Also, these two statements are contradictory:
For some reason, the program always reads that the sensor is HIGH, even if the sensor is not connected.
If I connect the output to a breadboard with an LED, I can see the LED toggle on and off.
So the program always reads high but the LED toggles on or off? Which one is it?
If you manually pull the pin to ground, does your program react the way it is supposed to? If it does, then you should take a look at your sensor circuit.
Your sensor circuit sounds weird - you say
I have a sensor that has 3 pins, 5VDC, ground, and sensor output. I connected the sensor output and ground header to the two pin slots at PORT0
So the sensor output and ground are connected to pin zero? 5v should go to 5v, ground should go to ground, the sensor output should go to pin zero.

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