I manage to send data from NodeJs runtime with serialport library.
The goal is storing a string received from Serial.read() in Arduino . What is correct:
int string = Serial.read()
or:
char string[20] = Serial.read()
There are many documentations on Internet and they are not the same
P/s: I send string from nodejs in buffer form but i dont think it matters because arduino still implement it as a string anyway.
From the Arduino documentation:
int incomingByte = 0; // for incoming serial data
void setup() {
Serial.begin(9600); // opens serial port, sets data rate to 9600 bps
}
void loop() {
// send data only when you receive data:
if (Serial.available() > 0) {
// read the incoming byte:
incomingByte = Serial.read();
// say what you got:
Serial.print("I received: ");
Serial.println(incomingByte, DEC);
}
}
https://www.arduino.cc/en/Serial/Read
.read():
Returns the first byte of incoming serial data available (or -1 if no
data is available) - int
FYI: I've used this code many times and it works on 100%.
Related
I am doing a project where I need to send data from ultrasonic sensor wirelessly present in one arduino to other arduino where I need these values in Serial monitor. But the problem is I cannot able to send these values through bluetooth. I tried to send one character, it is appearing in serial monitor.. But when I tried to the same for integer values it is not appearing in serial monitor.
I have configured Master and Slave modes for the Bluetooth. I have uploaded the image of the code which I am using to send these values. Please help me on this. Thanks in advance .
code
//# transmitting end
#define trigPin 12
#define echoPin 11
void setup() {
Serial.begin(38400); // Default communication rate of the Bluetooth module
pinMode(trigPin, OUTPUT);
pinMode(echoPin, INPUT);
}
void loop() {
long duration;
float distance;
digitalWrite(trigPin, LOW); // Added this line
delayMicroseconds(2); // Added this line
digitalWrite(trigPin, HIGH);
delayMicroseconds(10); // Added this line
digitalWrite(trigPin, LOW);
duration = pulseIn(echoPin, HIGH);
distance = (duration/2) / 29.1;
Serial.println(distance,2); // Sends floatValue
delay(500);
}
//# receving end
#include <SoftwareSerial.h>
#define led 13
SoftwareSerial BTSerial(10, 11);
int data=0;
void setup() {
pinMode(led,OUTPUT);
Serial.begin(38400);
BTSerial.begin(38400); // Default communication rate of the Bluetooth module
}
void loop() {
int number;
if(Serial.available() > 0){ // Checks data is from the serial port
data = BTSerial.read(); // Reads the data from the serial port
//analogWrite(led,data);
delay(10);
//Serial.println(data);
}
Serial.println(data);
}
I need integer values at the serial monitor. But there I am getting some symbols like ?/<>..
From the Arduino reference, Serial.read() only reads the first available byte available in the Serial buffer. As an int is coded on 8 bytes, I would say that you need to read the incoming bytes sequentially in order to get the full value.
Maybe you can implement this by putting (Serial.available() > 0) in a while loop, concatenate the values you get in a char[8] for instance and then convert this char to a integer value.
Also, beware that you are sending floats and not int.
Thanks for the help..!
I modified the code in the receiver end to get the float values from the transmitter.. Here is my modified code
#include <SoftwareSerial.h>
int bluetoothTx = 10;
int bluetoothRx = 11;
String content; //content buffer to concatenate characters
char character; //To store single character
SoftwareSerial bluetooth(bluetoothTx, bluetoothRx);
void setup(){
bluetooth.begin(38400);
Serial.begin(9600);
}
void loop(){
bluetooth();
}
void bluetooth(){ //
while(bluetooth.available()){
character = bluetooth.read();
content.concat(character);
if(character == '\r'){ // find if there is carriage return
Serial.print(content); //display content (Use baud rate 9600)
content = ""; //clear buffer
Serial.println();
}
}
}
I am using ESP8266 and ModbusMaster.h library to communicate with RS485 enabled power meter. Communication works fine but responses are the ones are confusing me and I can not get correct values. My power meter shows 1.49 kWh but response from Modbus is 16318. Here is my code:
#include <ArduinoOTA.h>
#include <BlynkSimpleEsp8266.h>
#include <SimpleTimer.h>
#include <ModbusMaster.h>
#include <ESP8266WiFi.h>
/*
Debug. Change to 0 when you are finished debugging.
*/
const int debug = 1;
#define ARRAY_SIZE(A) (sizeof(A) / sizeof((A)[0]))
int timerTask1, timerTask2, timerTask3;
float battBhargeCurrent, bvoltage, ctemp, btemp, bremaining, lpower, lcurrent, pvvoltage, pvcurrent, pvpower;
float stats_today_pv_volt_min, stats_today_pv_volt_max;
uint8_t result;
// this is to check if we can write since rs485 is half duplex
bool rs485DataReceived = true;
float data[100];
ModbusMaster node;
SimpleTimer timer;
// tracer requires no handshaking
void preTransmission() {}
void postTransmission() {}
// a list of the regisities to query in order
typedef void (*RegistryList[])();
RegistryList Registries = {
AddressRegistry_0001 // samo potrosnju
};
// keep log of where we are
uint8_t currentRegistryNumber = 0;
// function to switch to next registry
void nextRegistryNumber() {
currentRegistryNumber = (currentRegistryNumber + 1) % ARRAY_SIZE( Registries);
}
void setup()
{
// Serial.begin(115200);
Serial.begin(9600, SERIAL_8E1); //, SERIAL_8E1
// Modbus slave ID 1
node.begin(1, Serial);
node.preTransmission(preTransmission);
node.postTransmission(postTransmission);
// WiFi.mode(WIFI_STA);
while (Blynk.connect() == false) {}
ArduinoOTA.setHostname(OTA_HOSTNAME);
ArduinoOTA.begin();
timerTask1 = timer.setInterval(9000, updateBlynk);
timerTask2 = timer.setInterval(9000, doRegistryNumber);
timerTask3 = timer.setInterval(9000, nextRegistryNumber);
}
// --------------------------------------------------------------------------------
void doRegistryNumber() {
Registries[currentRegistryNumber]();
}
void AddressRegistry_0001() {
uint8_t j;
uint16_t dataval[2];
result = node.readHoldingRegisters(0x00, 2);
if (result == node.ku8MBSuccess)
{
for (j = 0; j < 2; j++) // set to 0,1 for two
datablocks
{
dataval[j] = node.getResponseBuffer(j);
}
terminal.println("---------- Show power---------");
terminal.println("kWh: ");
terminal.println(dataval[0]);
terminal.println("crc: ");
terminal.println(dataval[1]);
terminal.println("-----------------------");
terminal.flush();
node.clearResponseBuffer();
node.clearTransmitBuffer();
} else {
rs485DataReceived = false;
}
}
void loop()
{
Blynk.run();
// ArduinoOTA.handle();
timer.run();
}
I have tried similar thing but with Raspberry Pi and USB-RS485 and it works.
Sample of NodeJS code is below. It looks similar to Arduino code.
// create an empty modbus client
var ModbusRTU = require("modbus-serial");
var client = new ModbusRTU();
// open connection to a serial port
client.connectRTUBuffered("/dev/ttyUSB0", { baudRate: 9600, parity: 'even' }, read);
function write() {
client.setID(1);
// write the values 0, 0xffff to registers starting at address 5
// on device number 1.
client.writeRegisters(5, [0 , 0xffff])
.then(read);
}
function read() {
// read the 2 registers starting at address 5
// on device number 1.
console.log("Ocitavanje registra 0000: ");
client.readHoldingRegisters(0000, 12)
.then(function(d) {
var floatA = d.buffer.readFloatBE(0);
// var floatB = d.buffer.readFloatBE(4);
// var floatC = d.buffer.readFloatBE(8);
// console.log("Receive:", floatA, floatB, floatC); })
console.log("Potrosnja u kWh: ", floatA); })
.catch(function(e) {
console.log(e.message); })
.then(close);
}
function close() {
client.close();
}
This code displays 1.493748298302 in console.
How can I implement this var floatA = d.buffer.readFloatBE(0); in Arduino? Looks like that readFloatBE(0) does the trick, but available only in NodeJS / javascript.
Here i part of datasheet for my device
Here is what I am getting as result from original software that came with device:
If someone could point me in better direction I would be thenkfull.
UPDATE:
I found ShortBus Modbus Scanner software and tested readings.
Library read result as Unsigned integer, but need Floating Point and Word Order swapped. It is shown on image below.
Can someone tell how to set proper conversion please.
Right, so indeed the issue is with the part done by var floatA = d.buffer.readFloatBE(0);Modbus returns an array of bytes, and the client has to interpret those bytes, ideally done by the library you're using, but if not available on Arduino, you may try manually with byte decoding functions, with the following considerattions:
Modbus registers are 16 bit in length, so length 1 = 16 bits, length
2 = 32 bits, hence the data type noted on the docs as float32 means
"2 registers used for this value, interpret as float".
Therefore, on client.readHoldingRegisters(0000, 12)you're asking to read the register with address 00, and size 12... so this makes no sense, you only need 2 registers.
On your sample Node code, first you're writing
2 registers to address 5 in client.writeRegisters(5, [0 , 0xffff])
register 5 = 0, and register 6 = 0xFFFF, why? Then you go and read
from address 0, in read(), which is the address for Total KwH per
your docs.
So, you should get an array of bytes, and you need to
decode them as a float. Modbus is Big Endian for words and bytes, so
you need to use those in the decoding functions. I don't know exactly
what is available in Arduino, but hopefully you can figure it out
with this extra info.
I suppose that if you just send the buffer to print, you'll get an integer interpretation of the value, hence the problem
I want to use Arduino to read data from ADXL345 accelerometer and use raspberry pi with Processing to save the data into a txt file in pi. I used the code from https://www.researchgate.net/post/How_can_I_save_data_directly_in_the_pc_using_an_Arduino_UNO
And my Arduino code is shown as follows:
#include <Wire.h>
#define DEVICE (0x53) //ADXL345 device address
#define TO_READ (6) //num of bytes we are going to read each time (two bytes for each axis)
byte buff[TO_READ] ; //6 bytes buffer for saving data read from the device
char str[512]; //string buffer to transform data before sending it to the serial port
void setup()
{
Wire.begin(); // join i2c bus (address optional for master)
Serial.begin(9600); // start serial for output
//Turning on the ADXL345
writeTo(DEVICE, 0x2D, 0);
writeTo(DEVICE, 0x2D, 16);
writeTo(DEVICE, 0x2D, 8);
}
void loop()
{
int regAddress = 0x32; //first axis-acceleration-data register on the ADXL345
int x, y, z;
readFrom(DEVICE, regAddress, TO_READ, buff); //read the acceleration data from the ADXL345
//each axis reading comes in 10 bit resolution, ie 2 bytes. Least Significat Byte first!!
//thus we are converting both bytes in to one int
x = (((int)buff[1]) << 8) | buff[0];
y = (((int)buff[3])<< 8) | buff[2];
z = (((int)buff[5]) << 8) | buff[4];
//we send the x y z values as a string to the serial port
sprintf(str, "%d %d %d", x, y, z);
Serial.print(str);
Serial.write(10);
//It appears that delay is needed in order not to clog the port
delay(15);
}
void writeTo(int device, byte address, byte val) {
Wire.beginTransmission(device); //start transmission to device
Wire.write(address); // send register address
Wire.write(val); // send value to write
Wire.endTransmission(); //end transmission
}
void readFrom(int device, byte address, int num, byte buff[]) {
Wire.beginTransmission(device); //start transmission to device
Wire.write(address); //sends address to read from
Wire.endTransmission(); //end transmission
Wire.beginTransmission(device); //start transmission to device (initiate again)
Wire.requestFrom(device, num); // request 6 bytes from device
int i = 0;
while(Wire.available()) //device may send less than requested (abnormal)
{
buff[i] = Wire.read(); // receive a byte
i++;
}
Wire.endTransmission(); //end transmission
}
Processing code is shown as follows:
import processing.serial.*;
Serial mySerial;
PrintWriter output;
void setup() {
mySerial = new Serial( this, Serial.list()[0], 9600 );
output = createWriter( "/home/pi/data.txt" );
}
void draw() {
if (mySerial.available() > 0 ) {
String value = mySerial.readString();
if ( value != null ) {
output.println( value );
}
}
}
void keyPressed() {
output.flush(); // Writes the remaining data to the file
output.close(); // Finishes the file
exit(); // Stops the program
}
When only use serial monitor window to show x, y, z values, it looks well, but when using Processing to get data while Arduino serial monitor window is running, the data format changes, e.x. wrong format
Please help me.
I am working on a project in which I use a phone app that I built in order to use Google's Speech Recognizer, connect my phone with my Arduino via Bluetooth and then when I say a word it sends the word in order to display it in a LCD.
The phone App works great with no problems. The problem is in the Arduino code. When I say the word hello for example the Arduino receives ello. I know that it receives it because I also use the Serial monitor to display the data in my computer screen except the LCD. Then after Arduino receives the first chunk of data if I send a second word like world Arduino receives elloorld. So it not only misses again the first letter of the word but also the Serial Port is not empty it in the end of the loop.
I tried with data += c; instead of data.concat(c); and the difference is that the second word isn't elloorld and it is just orld
Here is my code:
#include <LiquidCrystal.h>
LiquidCrystal lcd(12, 11, 9, 8, 7, 6, 5, 4, 3, 2);
char c;
String data = "";
void setup() {
lcd.begin(16, 2);
Serial.begin(9600);
}
void loop() {
lcd.clear(); //clean the lcd
lcd.home(); // set the cursor in the up left corner
while(Serial.available() > 0){
c = Serial.read();
data.concat(c);
}
if(data.length() > 0){
Serial.println(data);
}
lcd.print(data);
delay(3000);
data = "";
}
If in the end of the loop I try to clean the Serial Port with this code:
while(Serial.available() > 0){
Serial.read();
}
Then the arduino doesn't receive data at all.
Your code wakes up every 3000 ms, then processes everything that is pending in the Serial input buffer and falls asleep again.
If you remove that ugly String data and the ugly delay(3000) and the unnecessary while, you can try this simple loop:
unsigned long lastreceived;
void loop() {
if (Serial.available()) {
lcd.write(Serial.read());
lastreceived=millis();
}
if (millis() - lastreceived > 1000) {
// after one second of silence, prepare for a new message
lcd.clear();
lcd.home();
lastreceived=millis(); // don't clear too often
}
}
I'm following this tutorial,
http://energia.nu/creating-an-iot-connected-sensor-with-energia-mqtt/
I see the pushed data, but the Node-RED editor constantly prints 'Hello World #XX'. I don't see anything in the code that would suggest where its coming from:
#include <WiFi.h>
#include <PubSubClient.h>
#include <SPI.h> //only required if using an MCU LaunchPad + CC3100 BoosterPack. Not needed for CC3200 LaunchPad
WiFiClient wclient;
byte server[] = { 198, 41, 30, 241 }; // Public MQTT Brokers: http://mqtt.org/wiki/doku.php/public_brokers
byte ip[] = { 172, 16, 0, 100 };
char sensorRead[4];
#define WIFI_SSID "SSID"
#define WIFI_PWD "WIFIPASSWORD"
PubSubClient client(server, 1883, callback, wclient);
void callback(char* inTopic, byte* payload, unsigned int length){
// Handle callback here
}
void setup()
{
//Initialize serial and wait for port to open:
Serial.begin(115200);
Serial.println("Start WiFi");
WiFi.begin(WIFI_SSID, WIFI_PWD);
while(WiFi.localIP() == INADDR_NONE) {
Serial.print(".");
delay(300);
}
Serial.println("");
printWifiStatus();
}
void loop()
{
// read the input on analog pin:
int sensorValue = analogRead(24);
Serial.println(sensorValue);
// convert into to char array
String str = (String)sensorValue;
int str_len = str.length() + 1; // Length (with one extra character for the null terminator)
char char_array[str_len]; // Prepare the character array (the buffer)
str.toCharArray(char_array, str_len); // Copy it over
// publish data to MQTT broker
if (client.connect("LaunchPadClient")) {
client.publish("outTopic", char_array);
//client.subscribe("inTopic");
Serial.println("Publishing successful!");
client.disconnect();
}
}
void printWifiStatus() {
// print the SSID of the network you're attached to:
Serial.print("SSID: ");
Serial.println(WiFi.SSID());
// print your WiFi shield's IP address:
IPAddress ip = WiFi.localIP();
Serial.print("IP Address: ");
Serial.println(ip);
}
Is this because this is a free/trial account? Incidentally, it shows I'm using 512MB/2GB, which seems high... does it include the data sent, or is 512MB just the application size?
You are using a MQTT broker that is public to the world, anybody can publish data to any topic on that broker. The messages are probably coming from somebody else doing similar experiments to yourself.
outTopic is the sort of topic name that many people could be using to test, try changing it to some random string in both the publishing code and the MQTT In node in Node-RED.
As for the size in Bluemix, this is how much memory is assigned to your application, it is unlikely to be actually using anything near that amount at the moment.