I working on project about seat occupancy in which I have used an Arduino, a piezoelectric sensor and an ESP8266. My problem is that I am not able to send data to my PC where an UDP server is running, written in Python.
My real problem is, that I am able to send data, when I use Arduino IDE's serial monitor. It sends and receives data perfectly, but code is not running and I am not able to point out my mistake.
Arduino code:
const int seat_no = 2;
const char *ssid = "";
const char *passwd = "";
const char *ip = "192.168.43.250";
const int port = 55056;
const int threshold = 100;
String op;
int i, a, data_size;
void setup() {
Serial.begin(9600);
Serial1.begin(115200);
Serial.println("Starting ESP8266");
Serial1.write("AT+CWJAP=\"");
Serial1.write(ssid);
Serial1.write("\",\"");
Serial1.write(passwd);
Serial1.write("\"\r\n");
Serial1.write("AT+CWMODE=1\r\n");
Serial1.write("AT+CIPMUX=0\r\n");
Serial1.write("AT+CIPSTART=\"UDP\",\"");
Serial1.write(ip);
Serial1.write("\",");
Serial1.write(port);
Serial1.write("\r\n");
}
void loop() {
op = "{\"seat_status\":[";
for (i = 0; i < seat_no; i++) {
a = analogRead(i);
if (a > threshold) {
op += "\"0\"";
Serial.println("0");
}
else {
op += "\"1\"";
Serial.println("1");
}
if (i < seat_no - 1)
op += ",";
}
op += "]}";
data_size = op.length();
Serial1.write("AT+CIPSEND=");
Serial1.write(data_size+2);
Serial1.write("\r\n");
delay(1000);
for (i = 0; i < data_size; i++)
Serial.write(op[i]);
Serial.println();
for (i = 0; i < data_size; i++)
Serial1.write(op[i]);
Serial1.write("\r\n");
delay(5000);
}
I think my Python code is correct as I am able to receive data from other sources as well (through Android app UDP sender) so help me to rectify this problem.
Circuit Diagram
The problem is with the use of Serial1.write. It's a lower level function. All it does is send bytes and doesn't convert numbers to their string representation.
When you are writing your port and length of your data to the serial, the write function is just sending a byte with that value and not a string.
If you would replace Serial1 with Serial and send the commands back to PC, you would see the mistake.
To actually solve your problem, you should replace all of your Serial1.write with Serial1.print.
Related
I have a strange problem with trying to write data to a serial port.
I am running Ubuntu 16.04 on a NUC7i7DNBE, and am trying to make a serial connection to an Arduino UNO. The Serial API that I am using is found here: http://docs.ros.org/kinetic/api/serial/html/classserial_1_1Serial.html
I have written a simple program which opens the serial port "ttyACM0" to communicate with the arduino. I have tested this code on another computer running Ubuntu 16.04, and everything worked fine, the only permissions I had to set where adding the user to the dialout group.
On the NUC, however, I have added the user to the dialout group. This allowed the program to read from the Arduino, but it still does not write to the Arduino. The Arduino IDE will write to the Arduino just fine, but my program will not.
I am assuming that I am having trouble with serial write permissions in Ubuntu.
Steps I have taken:
I have added the user to the dialout group
I have added a rule in /etc/udev/rules.d/ which states:
SUBSYSTEMS=="tty", GROUP="dialout", MODE="0666"
Afterward, I sent the commands:
sudo chown root:root /etc/udev/rules.d/50-AVCusb.rules
sudo chmod 0644 /etc/udev/rules.d/50-AVCusb.rules
udevadm control --reload-rules
I followed some information found on stack exchange to get to this point:
https://unix.stackexchange.com/questions/111593/allow-non-root-user-to-read-write-dev-files
I have tried using an FTDI device to write to the Arduino port. The FTDI device uses the ttyUSB0 port rather than the ttyACM0 port. The result was the same; can read, but can't write.
I have also run my external hard-drive on the NUC to see if there was any kind of hardware issue. When I ran the program from my external hard drive, I had no problem reading from and writing to the Arduino.
I have not dealt much with Ubuntu permissions or ports in general, please help me find and upload any other information that you may need in order to help me solve this problem.
Code on NUC:
#include <ros/ros.h>
#include <serial/serial.h>
using namespace serial;
Serial ser;
static const uint8_t MOTOR_ID = 0;
void writeMotor(uint8_t byte)
{
size_t size = 4;
uint8_t buffer[size];
buffer[0] = 'G'; //PID
buffer[1] = 'O';
buffer[2] = MOTOR_ID; //address
buffer[3] = byte; //data byte
ser.write(buffer, size);
}
int main() {
ros::init(argc, argv, "servo_esc_driver");
std::string port = "/dev/ttyACM0";
Timeout timeout = Timeout(0, 0, 0, 0, 0);
bytesize_t bytesize = eightbits;
parity_t parity = parity_none;
stopbits_t stopbits = stopbits_one;
flowcontrol_t flowcontrol = flowcontrol_none;
try{
ser.setPort(port);
ser.setBaudrate(115200);
ser.setTimeout(timeout);
ser.setBytesize(bytesize);
ser.setParity(parity);
ser.setStopbits(stopbits);
ser.setFlowcontrol(flowcontrol);
ser.open();
}
catch (SerialException e) {
ROS_FATAL_NAMED("Failed to connect to the Arduino UNO, %s.", e.what());
ros::shutdown();
return 0;
}
uint8_t byte = 90;
writeMotor(byte);
}
Full Code on Arduino
#include <Servo.h>
const byte N = 2;
//Servo esc;
//Servo servo;
Servo servo[N];
//int escPos = 90;
//int servoPos = 90;
int pos[N];
static const byte ESC_PIN = 7;
static const byte SERVO_PIN = 8;
static const byte RPM_FEEDBACK_PIN = 0; //interrpt 0, pin 2
static const byte SERVO_FEEDBACK_PIN = A0;
//const float MUL = 0.7058823529; //180/255
unsigned long lastTime_servoFeedback = 0;
static const byte MOTOR_ID = 0; //ID for differentiating data received and sent over serial connections
static const byte SERVO_ID = 1;
//added for motor data timeout safety feature
static const unsigned long MOTOR_DATA_TIMEOUT = 200; //4 x 50 ms (50 ms time period expected)
static unsigned long lastTimeMotorData = 0;
static const byte NEUTRAL = 90;
unsigned long last_rpm_pulse_update_ms = 0; //used for detecting a stopped car, and rejecting old data when writing to the serial port
unsigned long last_rpm_pulse_time_us = 0;//keeps track of rpms by comparing to system timer
static const long REV_PERIOD_MAX_US = 100000; //in us
unsigned long rev_period = REV_PERIOD_MAX_US; //100 ms is considered too long to be in motion
boolean forward = true;
/*Scratch that, I want these parameters set in ROS:
static const float wheel_radius = 0.05 // meters
static const float revs_to_mps_MUL = //assuming 2.85 gear ratio for brushless motor differential: https://forums.traxxas.com/showthread.php?9080733-Diff-gear-ratios
*/
//boolean rpm_period_updated = false; //rpms must be updated every 100 ms, otherwise the car has stopped, and velocity data should show 0 m/s
void rpm_feedback()
{
//Serial.println("in rpm_feedback");
last_rpm_pulse_update_ms = millis(); //notice the 'ms' here we want to use millisecond for checking whether or not data is valid. millis() can count up to 50 days while micros() only counts up to 70 minutes, thus millis() is used here.
unsigned long time_now = micros(); //use time now for accurate time calculations
unsigned long rev_period_temp = time_now - last_rpm_pulse_time_us; //get spur-gear revolution period
if(rev_period_temp > 0) rev_period = rev_period_temp; //revs are within
else rev_period = REV_PERIOD_MAX_US;
last_rpm_pulse_time_us = time_now; //using 'time_now' ensures that the time taken to get to this point in code does not interfere with rev_period accuracy - - - micros(); //reset time
if(pos[MOTOR_ID] < 90) //determine the direction that the vehicle is traveling in
{
forward = false;
}else forward = true;
//rpm_period_updated = true; not needed, only last_rpm_pulse_time_ms is needed for checking
}
void setup() {
// put your setup code here, to run once:
pinMode(RPM_FEEDBACK_PIN, INPUT_PULLUP);
attachInterrupt(RPM_FEEDBACK_PIN, rpm_feedback,FALLING); //arduino reference recommends using digitalPinToInterrupt(RPM_FEEDBACK_PIN) but the command is not recognized here
analogReference(EXTERNAL); //Using external reference for servo position
for(int i = 0; i < N; i++) //initialize
{
pos[i] = 90;
servo[i].attach(ESC_PIN + i);
}
Serial.begin(115200);
}
void loop() {
// put your main code here, to run repeatedly:
if(Serial.available() >= 1)
{
if(Serial.read() == 'G')
{
unsigned long t = millis();
while((Serial.available() < 3) && ((millis() - t) < 10)); //wait for the rest of the package, or timeout
if(Serial.available() >= 3)
{
char buf[3];
Serial.readBytes(buf, 3);
if((buf[0] == 'O') && (buf[1] >= 0) && (buf[1] < 2))
{
pos[buf[1]] = byte(buf[2]);
if(buf[1] == MOTOR_ID) lastTimeMotorData = millis(); //time stamp of last motor data retrieval
//Serial.print("buf[2]: ");
//Serial.println(byte(buf[2]), DEC);
//Serial.print("pos: ");
//Serial.println(pos[buf[1]]);
}
}
}
}
if((millis() - lastTimeMotorData) > MOTOR_DATA_TIMEOUT) pos[MOTOR_ID] = NEUTRAL; //stop the motor if data is not being received
for(int i = 0; i < N; i++)
{
servo[i].write(pos[i]);
}
if((millis() - lastTime_servoFeedback) >= 50) // 20Hz 20) //50Hz matches current ROS driver settings
{
lastTime_servoFeedback = millis();
int servo_feedback = analogRead(SERVO_FEEDBACK_PIN);
Serial.write('G'); //PID
Serial.write('O');
Serial.write(SERVO_ID);
//Serial.print(servo_feedback);
Serial.write(lowByte(servo_feedback));
Serial.write(highByte(servo_feedback));
//Serial.println(servo_feedback);
float rev_frequency;
if((last_rpm_pulse_update_ms + 100) < millis()) rev_frequency = 0; //use millis() since it can count up to 50 days, and will not have a chance of a hiccup after 70 minutes of using micros()
//instead, correct period when slowing down, also stop when the maximum threshold is reached
//if((micros() - last_rpm_pulse_time_us) >= REV_PERIOD_MAX_US) rev_frequency = 0; //car is stopped in this case. I decided not to try correcting the period as mentioned above
else rev_frequency = (float) 1/rev_period*1000000;
byte *rev_freq_bytes_to_transmit = (byte *) &rev_frequency;
if(forward == false) rev_frequency = -rev_frequency; //a negative frequency is used for reverse
Serial.write('G'); //PID
Serial.write('O');
Serial.write(MOTOR_ID); //used for addressing
Serial.write(rev_freq_bytes_to_transmit, 4);
}
}
Some good information may be:
snuc#usuavc:~$ udevadm info -a -n /dev/ttyACM0
Udevadm info starts with the device specified by the devpath and then
walks up the chain of parent devices. It prints for every device
found, all possible attributes in the udev rules key format.
A rule to match, can be composed by the attributes of the device
and the attributes from one single parent device.
looking at device '/devices/pci0000:00/0000:00:14.0/usb1/1-4/1-4:1.0/tty/ttyACM0':
KERNEL=="ttyACM0"
SUBSYSTEM=="tty"
DRIVER==""
looking at parent device '/devices/pci0000:00/0000:00:14.0/usb1/1-4/1-4:1.0':
KERNELS=="1-4:1.0"
SUBSYSTEMS=="usb"
DRIVERS=="cdc_acm"
ATTRS{authorized}=="1"
ATTRS{bAlternateSetting}==" 0"
ATTRS{bInterfaceClass}=="02"
ATTRS{bInterfaceNumber}=="00"
ATTRS{bInterfaceProtocol}=="01"
ATTRS{bInterfaceSubClass}=="02"
ATTRS{bNumEndpoints}=="01"
ATTRS{bmCapabilities}=="6"
ATTRS{supports_autosuspend}=="1"
looking at parent device '/devices/pci0000:00/0000:00:14.0/usb1/1-4':
KERNELS=="1-4"
SUBSYSTEMS=="usb"
DRIVERS=="usb"
ATTRS{authorized}=="1"
ATTRS{avoid_reset_quirk}=="0"
ATTRS{bConfigurationValue}=="1"
ATTRS{bDeviceClass}=="02"
ATTRS{bDeviceProtocol}=="00"
ATTRS{bDeviceSubClass}=="00"
ATTRS{bMaxPacketSize0}=="8"
ATTRS{bMaxPower}=="100mA"
ATTRS{bNumConfigurations}=="1"
ATTRS{bNumInterfaces}==" 2"
ATTRS{bcdDevice}=="0001"
ATTRS{bmAttributes}=="c0"
ATTRS{busnum}=="1"
ATTRS{configuration}==""
ATTRS{devnum}=="4"
ATTRS{devpath}=="4"
ATTRS{idProduct}=="0043"
ATTRS{idVendor}=="2341"
ATTRS{ltm_capable}=="no"
ATTRS{manufacturer}=="Arduino (www.arduino.cc)"
ATTRS{maxchild}=="0"
ATTRS{quirks}=="0x0"
ATTRS{removable}=="removable"
ATTRS{serial}=="55330313635351207081"
ATTRS{speed}=="12"
ATTRS{urbnum}=="6990"
ATTRS{version}==" 1.10"
looking at parent device '/devices/pci0000:00/0000:00:14.0/usb1':
KERNELS=="usb1"
SUBSYSTEMS=="usb"
DRIVERS=="usb"
ATTRS{authorized}=="1"
ATTRS{authorized_default}=="1"
ATTRS{avoid_reset_quirk}=="0"
ATTRS{bConfigurationValue}=="1"
ATTRS{bDeviceClass}=="09"
ATTRS{bDeviceProtocol}=="01"
ATTRS{bDeviceSubClass}=="00"
ATTRS{bMaxPacketSize0}=="64"
ATTRS{bMaxPower}=="0mA"
ATTRS{bNumConfigurations}=="1"
ATTRS{bNumInterfaces}==" 1"
ATTRS{bcdDevice}=="0415"
ATTRS{bmAttributes}=="e0"
ATTRS{busnum}=="1"
ATTRS{configuration}==""
ATTRS{devnum}=="1"
ATTRS{devpath}=="0"
ATTRS{idProduct}=="0002"
ATTRS{idVendor}=="1d6b"
ATTRS{interface_authorized_default}=="1"
ATTRS{ltm_capable}=="no"
ATTRS{manufacturer}=="Linux 4.15.0-32-generic xhci-hcd"
ATTRS{maxchild}=="12"
ATTRS{product}=="xHCI Host Controller"
ATTRS{quirks}=="0x0"
ATTRS{removable}=="unknown"
ATTRS{serial}=="0000:00:14.0"
ATTRS{speed}=="480"
ATTRS{urbnum}=="76"
ATTRS{version}==" 2.00"
looking at parent device '/devices/pci0000:00/0000:00:14.0':
KERNELS=="0000:00:14.0"
SUBSYSTEMS=="pci"
DRIVERS=="xhci_hcd"
ATTRS{broken_parity_status}=="0"
ATTRS{class}=="0x0c0330"
ATTRS{consistent_dma_mask_bits}=="64"
ATTRS{d3cold_allowed}=="1"
ATTRS{dbc}=="disabled"
ATTRS{device}=="0x9d2f"
ATTRS{dma_mask_bits}=="64"
ATTRS{driver_override}=="(null)"
ATTRS{enable}=="1"
ATTRS{irq}=="122"
ATTRS{local_cpulist}=="0-7"
ATTRS{local_cpus}=="ff"
ATTRS{msi_bus}=="1"
ATTRS{numa_node}=="-1"
ATTRS{revision}=="0x21"
ATTRS{subsystem_device}=="0x2070"
ATTRS{subsystem_vendor}=="0x8086"
ATTRS{vendor}=="0x8086"
looking at parent device '/devices/pci0000:00':
KERNELS=="pci0000:00"
SUBSYSTEMS==""
DRIVERS==""
I decided that the problem was with the ROS version of serial. I decided to try some native linux library, termios, and had success writing to the port!
I found this example code:
https://en.wikibooks.org/wiki/Serial_Programming/Serial_Linux
The problem lies in the ros serial installation somehow.
Don't know if you still want to solve this with serial/serial.h, but I think that your problem might be in the timeout settings.
I'm telling you this, 'cause I had the exact same problem, I could read the incoming data, but couldn't write.
The /dev/ttyUSB0 permission was ok, but not the timeout.
I found the following config on internet, gave a try and work. Now I can read and write.
try{
ser.setPort("/dev/ttyUSB0");
ser.setBaudrate(9600);
serial::Timeout to = serial::Timeout::simpleTimeout(10);
ser.setTimeout(to);
ser.open();
return true;
}
catch (SerialException e) {
return 0;
I want to do project which will use GPS & GSM module, use Arduino, take data from GPS(GY-GPS/NEO6MV2) and send by GSM(SIM900 GSM/GPRS Module ) to my phone. I am using separate GPS module
I try this code but still have problem.
#include <SoftwareSerial.h>
#include "SIM900.h"
#include <TinyGPS.h>
#include "sms.h"
SMSGSM sms;
TinyGPS gps;
SoftwareSerial ss(4, 3);
SoftwareSerial SIM900(7, 8);
static void smartdelay(unsigned long ms);
static void print_float(float val, float invalid, int len, int prec);
static void print_int(unsigned long val, unsigned long invalid, int len);
static void print_date(TinyGPS &gps);
static void print_str(const char *str, int len);
String strL, strN, message, textForSMS;
char charL[10], charN[10], text[200];
int m = 1;
boolean started = false;
void setup()
{
Serial.begin(9600);
ss.begin(9600);
gsm.begin(9600);
}
void loop()
{
float flat, flon;
unsigned long age, date, time, chars = 0;
unsigned short sentences = 0, failed = 0;
gps.f_get_position(&flat, &flon, &age);
textForSMS = "Moosa Home"; //testing gps from here
Serial.println(textForSMS);
Serial.println(flat, 6);
Serial.println(flon, 6);
Serial.print("longitude: ");
print_float(flat, TinyGPS::GPS_INVALID_F_ANGLE, 10, 6);
Serial.println("");
Serial.print("latitude : ");
print_float(flon, TinyGPS::GPS_INVALID_F_ANGLE, 10, 6);
smartdelay(1000);
Serial.println(""); //till here
delay(1000);
if (m == 5) //send sms on third reading
{
Serial.println("XXXXXXXXX"); //to check whether 'if' works
dtostrf(flat, 4, 6, charL);
for (int i = 0; i < 10; i++)
{
strL += charL[i];
}
dtostrf(flon, 4, 6, charN);
for (int i = 0; i < 10; i++)
{
strN += charN[i];
}
message = "Home";
message = message + "/nLat: ";
message = message + strL;
message = message + "/nLon: ";
message = message + strN;
message.toCharArray(text, 250);
Serial.println(text);
if (sms.SendSMS("+999999999999999", text))
{
Serial.println("\nSMS sent OK.");
}
else
{
Serial.println("\nError sending SMS.");
}
do {} while (1);
}
m++;
}
static void smartdelay(unsigned long ms)
{
unsigned long start = millis();
do
{
while (ss.available())
gps.encode(ss.read());
} while (millis() - start < ms);
}
static void print_float(float val, float invalid, int len, int prec)
{
if (val == invalid)
{
while (len-- > 1)
Serial.print('*');
Serial.print(' ');
}
else
{
Serial.print(val, prec);
int vi = abs( val);
int flen = prec + (val < 0.0 ? 2 : 1); // . and -
flen += vi >= 1000 ? 4 : vi >= 100 ? 3 : vi >= 10 ? 2 : 1;
for (int i = flen; i < len; ++i)
Serial.print(' ');
}
smartdelay(0);
}
static void print_str(const char *str, int len)
{
int slen = strlen(str);
for (int i = 0; i < len; ++i)
Serial.print(i < slen ? str[i] : ' ');
smartdelay(0);
}
I receive SMS
Home/nLat:1000.00000/nLon:1000.00000`
where is my mistake in this code?
I am sure Gps & gsm work properly
Using TinyGPS on SoftwareSerial + a loop() structure using delay(1000), has very low odds of working. The m counter is really useless here, because loop() will execute 1000's of times while the GPS characters are arriving. And doing a get_position is useless, because you may not have any GPS data yet.
Basically, loop() should be constantly running, without delays. When something important happens (like getting all of a GPS sentence, or enough time has passed), that's when you do your other work (like send an SMS message). The TinyGPS smartDelay is not smart.
You should restructure the loop to look more like this example from the NeoGPS library. All the non-GPS work should be performed where the digitalWrite is in that example (line 62). That's where you would take the time to send an SMS.
The TinyGPS examples would require a complete rewrite to do what you want. They are fine by themselves, but it is difficult to extend them to do other things, like send an SMS. As I said, the loop structure must change.
I suggest taking a look at the NeoGPS library I wrote, as the examples are more robust. The library also uses much less RAM and CPU time, but that isn't a big problem if all you need to do is send an SMS message. If you do want to try it, be sure to review the default SoftwareSerial choice.
If you get the simple NMEAblink.ino example to work, I would suggest trying NMEA.ino. Then insert your code into the doSomeWork function. Most of what you have in loop needs to go in the doSomeWork function, which is called only when a complete RMC sentence is received.
Regardless of which library you use, you also need to check whether the data is valid. What if your GPS isn't receiving any satellites? It may still send an RMC sentence, but there won't be any lat/lon data. You probably shouldn't send an SMS if the location field is not valid.
I have been working on a project which involves xbees. My set-up is simply one Xbee ( coordinator Api mode ) connected to an Arduino as a master unit. This master unit recieves data from multiple Xbees ( slaves ) that are only powered up by a battery and reading data from there ADC pin17. ADC values are transmitted to the master xbee to display it on the serial terminal. The slaves Xbee are configured as ( Router AT mode ). I've bee doing this between two xbees only : 1 master and 1 slave. I have a code that reads the mac address of the sending Xbee and then displays the sent ADC value which is transmitted. All of that was ok until I added another slave, I really need help since I can't associate each mac address with the right ADC value. Neither my code is capable of reading from both alternatively; at some point it stops reading from a one. If any advice on how to recognize data coming from multiple xbees on the same network, I will be grateful.
Here's my code :
#include <XBee.h>
#include <SoftwareSerial.h>
SoftwareSerial myserial(5,6);
float distance;
uint8_t myaddress[10];
XBee xbee = XBee();
uint8_t shCmd[] = {'S','H'};
uint8_t slCmd[] = {'S','L'};
AtCommandRequest atRequestSH = AtCommandRequest(shCmd);
AtCommandRequest atRequestSL = AtCommandRequest(slCmd);
AtCommandResponse atResponse = AtCommandResponse();
void getMyAddress(){
xbee.send(atRequestSL);
if(xbee.readPacket(5000)){
xbee.getResponse().getAtCommandResponse(atResponse);
if (atResponse.isOk()){
for(int i = 0; i < atResponse.getValueLength(); i++){
myaddress[i] = atResponse.getValue()[i];
}
}
}
delay(100);
}
void setup(){
Serial.begin(1200);
myserial.begin(1200);
xbee.begin(myserial);
}
void loop() {
getMyAddress();
for(int i=0; i < 10; i++) {
Serial.print(myaddress[i], HEX);
Serial.print(" ");
}
Serial.print("\n");
if (myserial.available() >= 21) { //
if (myserial.read() == 0x7E) {
for (int i = 1; i<19; i++) { // Skip ahead to the analog data
byte discardByte = myserial.read();
}
int analogMSB = myserial.read(); // Read the first analog byte data
int analogLSB = myserial.read(); // Read the second byte
int analogReading = analogLSB + (analogMSB * 256);
distance = ((analogReading *1.0) / 1023.0)* 3.3;
Serial.println(distance);
}
}
}
In the code where you're skipping data to get to the analog value, you'll find the MAC address of the device sending the data.
if (myserial.read() == 0x7E) {
for (int i = 1; i<19; i++) { // Skip ahead to the analog data
byte discardByte = myserial.read();
}
You should be taking a closer look at that data before processing it -- ensure that it's an I/O sample by looking at the frame type, check the frame length, check the checksum at the end of the frame, etc. The library you're using appears to have functions for processing AT commands and responses, perhaps it also has functions for the I/O Sample frame type.
This Digi support page explains I/O sampling and documents the various fields in the IO Data Sample Received frame (type 0x92).
I have 2 Arduinos Leonardo and I want them to communicate itself, so I did the following code:
void setup() {
Serial.begin(9600);
Serial1.begin(9600);
}
void loop() {
String outMessage = ""; // String to hold input
while (Serial.available() > 0) { // check if at least 1 char is available
char inChar = Serial.read();
outMessage.concat(inChar); // add inChar to outMessage
}
if (outMessage != "") {
Serial.println("Sent: " + outMessage); // View Arduino 1 in Serial Monitor 1
Serial1.print(outMessage); // Send to Arduino 2
}
while (Serial1.available() > 0) {
Serial.print("Received: "); // View Arduino 1 in Serial Monitor 2
Serial.print(Serial1.read()); // Received from Arduino 1
Serial.println();
}
}
I want to send a message from Arduino 1, print in Serial Monitor and send via TX1 to Arduino 2 and vice-versa. The problem is that I don't receive what I was expecting. For instance if I type test:
Arduino 1:
Sent: test
Arduino 2:
Received: t
Received: e
Received: s
Received: t
I also tryed to do the receiving side like the sending side and use Serial.write but with no sucess.
Is there a easier way to do that or to fix it?
Thanks
Has mentioned by Hans, you need a protocol.
This is what I use to consider a message in Arduino to be a complete message:
char inData[10];
int index;
boolean started = false;
boolean ended = false;
String message =("I am Arduino 1 and I am ready");
void setup(){
Serial.begin(9600);
Serial.println(message);
}
void loop()
{
while(Serial.available() > 0)
{
char aChar = Serial.read();
if(aChar == '>')
{
started = true;
index = 0;
inData[index] = '\0';
}
else if(aChar == '<')
{
ended = true;
}
else if(started)
{
inData[index] = aChar;
index++;
inData[index] = '\0';
}
}
if(started && ended)
{
int inInt = atoi(inData);
Serial.println(inInt);
}
// Get ready for the next time
started = false;
ended = false;
index = 0;
inData[index] = '\0';
}
So, basically a message is considered completed only if it is between the special characters ><, like this: >message<. Then you can do the same on reading.
It does not have to be too complicated. If you look carefully at your last whlie-loop you can see that the software does not get a chance to read more than one character each time it passes through the loop. So that is what you get: one character at a time.
In your first while-loop you did better: you collected all the incoming letters until nothing was available and then sent them all at once. So if you make your last loop look more like the first one, you'll get a better result.
As mentioned a protocol to frame messages is needed between devices. A quick way to do this is to use Bill Porter's EasyTransfer library which does exactly what you are trying to do, over either UART or I2C. It has several examples.
Serial.read() reads only one byte every time you use it. A simple solution would be to store each byte on a char array while Serial.available>0 and then print the String with the whole message that was sent.
char message[40];
int count = 0;
while(Serial.available()>0){
message[count++] = Serial.read();
}
Serial.println(message);
I have a trouble with xbee s2b.
I try to receive two joystick values using only xbee placed on sparkfun regulated board (Coordinator API) and process these data on Arduino Uno connected to other xbee s2b placed on explorer board.(Router API). I configured xbees using X-CTU properly and I adjusted DIO0 and DIO1 to ADC[2] on Router Xbee. There is no problem when working with one joystick. But when I try to receive two joystick values at the same time, they are not working correctly. When I look the incoming data on serial monitor, I see;
https://lh3.googleusercontent.com/-20vjr0EchsQ/VqyZXgq84VI/AAAAAAAAA_0/WhEtoOU61vA/s1280-Ic42/Screenshot_3.jpg
My Arduino code is:
int packet[32];
void setup()
{
Serial.begin(9600);
}
void loop(){
if (Serial.available() > 0) {
if (Serial.read() == 0x7E) {
packet[0] = 0x7E; //start delimiter
packet[1] = readByte(); //MSB1
packet[2] = readByte(); //MSB2
int dataLength = (packet[1] << 8) | packet[2]; //between the length and the checksum
printPacket(dataLength+4);
Serial.println("");
}
}
delay(1000);
}
void printPacket(int k) {
for(int i=0; i < k; i++) {
Serial.print(packet, HEX);
Serial.print(" ");
delay(1000);
}
}
int readByte() {
while (true) {
if (Serial.available() > 0) {
return Serial.read();
}
}
}
What is the point I missed? Can you help me about this issue. Thank you in advance.
The delay(1000) statements may be causing you to lose characters from your serial buffer, and might not be necessary.
The code you shared appears incomplete. Where are you reading the dataLength bytes of the packet? How does printPacket() print the bytes?
Your inbound packet buffer should be larger -- I think the XBee S2B can have network payloads of up to 255 characters, in addition to the frame header and checksum.
You've created a blocking readByte() call, which isn't good program design. Consider something like this instead:
unsigned char packet[300];
int packet_index = 0;
int packet_length;
void loop() {
while (Serial.available() > 0) {
packet[packet_index++] = Serial.read();
if (packet_index == 3) {
packet_length = (packet[1] << 8) | packet[2];
}
if (packet_index > 2 && packet_index == packet_length) {
print_packet();
packet_index = 0;
}
}
}
void print_packet() {
int i;
for (i = 0; i < packet_length; ++i) {
Serial.print(packet[i], HEX);
Serial.print(" ");
}
Serial.println("");
}
If you have too much data to print and you're overflowing your outbound serial buffer, try increasing the speed of the console's serial port to 115200bps. Or print the bytes as you receive them instead of waiting until the packet is complete.