I have multiple Arduinos. I will use one of them as master and it must share variables to other Arduinos. For example, master Arduino will change integer A value, and this integer A value will be changed at other Arduinos as well. How do I connect or communicate those multiple Arduinos? Thanks in advance for any kind of suggestions.
I did some research and found how to communicate between two Arduinos. First, we will upload codes below then connect our Arduinos as in this image:
Connection of Arduinos
If you connect Arduinos before uploading codes, Arduino will give an error. So be sure that you upload your codes before connection. Here is receiver code:
After that, you will receive exact value from sender arduino. You can check it on receiver serial port screen. Hope this helps everyone :)
//Receiver Arduino Code
String a;
int yyy;
void setup()
{
Serial.begin(9600);
}
void loop()
{
while(Serial.available())
{
a = Serial.readString(); //reading value as String
//yyy=a.toInt(); //this one is for the converting string value to if it is an integer
Serial.println(a);
Serial.println(a.length());
Serial.println(a.charAt(a.length()-1));
}
}
Here is sender code:
//Sender Arduino code
void setup()
{
Serial.begin(9600);
}
void loop()
{
Serial.println("1234i");
delay(2000);
}
Related
I'm trying to use encoders to track the movement of three wheels on a robot, but as soon as any of the motors move the robot "locks up", it stops responding to commands, stops printing to the serial monitor, and just keeps spinning its wheels until I turn it off. I cut out everything except just the code to track one encoder and tried turning the wheel by hand to sus out the problem, but it still locked up. And even more strangely, now it will start spinning one of the wheels even though I've removed any code that should have it do that, even by mistake.
I used the Arduino IDE to program the pico since I've got no familiarity with python, but I can't find any information or troubleshooting tips for using interrupts with the pico that don't assume you're using micropython.
Here's the simplified code I'm using to try to find the problem. All it's meant to do is keep track of how many steps the encoder has made and print that to the serial monitor every second. Ive tried removing the serial and having it light up LEDs instead but that didn't help.
int encA = 10;
int encB = 11;
int count = 0;
int timer = 0;
void setup() {
// put your setup code here, to run once:
Serial.begin(9600);
attachInterrupt(digitalPinToInterrupt(encA),readEncoder,RISING);
timer = millis();
}
void loop() {
// put your main code here, to run repeatedly:
if (timer - millis() > 5000) {
Serial.println(count);
timer = millis();
}
}
void readEncoder() {
int bVal = digitalRead(encB);
if (bVal == 0) {
count--;
}
else{
count++;
}
}
Does the mapping function digitalPinToInterrupt for the Pi Pico work?
Can you try just using the interrupt number that corresponds to the pi?
attachInterrupt(9,readEncoder,RISING); //Or the number 0-25 which maps to that pin
https://raspberrypi.github.io/pico-sdk-doxygen/group__hardware__irq.html
You have the wrong pin to encoder in your example (maybe you incorrectly copy and pasted)?
attachInterrupt(digitalPinToInterrupt(**encA**),readEncoder,RISING);
void readEncoder() {
int bVal = digitalRead(**encB**); ...}
There is similar code on GitHub that you could modify and try instead.
https://github.com/jumejume1/Arduino/blob/master/ROTARY_ENCODER/ROTARY_ENCODER.ino
It might help you find a solution.
Also,
https://www.arduino.cc/reference/en/libraries/rpi_pico_timerinterrupt/
The interrupt number corresponds to the pin (unless you have reassigned it or disabled it) so for pin 11 the code can be:
attachInterrupt(11, buttonPressed, RISING);
This works:
bool buttonPress = false;
unsigned long buttonTime = 0; // To prevent debounce
void setup() {
Serial.begin(9600);
pinMode(11, INPUT_PULLUP);
attachInterrupt(11, buttonPressed, RISING);
// can be CHANGE or LOW or RISING or FALLING or HIGH
}
void loop() {
if(buttonPress) {
Serial.println(F("Pressed"));
buttonPress= false;
} else {
Serial.println(F("Normal"));
}
delay(250);
}
void buttonPressed() {
//Set timer to work for your loop code time
if (millis() - buttonTime > 250) {
//button press ok
buttonPress= true;
}
buttonTime = millis();
}
See: https://raspberrypi.github.io/pico-sdk-doxygen/group__hardware__irq.html for disable, enable etc.
On the circuit playground express theres a network function, where you can send a number through ir. Now I would like my arduino to read this number, and respond when it reads the number.
I've already connected a IR Receiver Diode to my arduino and used the following code with library:
#include <IRremote.h>
int RECV_PIN = 11;
IRrecv irrecv(RECV_PIN);
decode_results results;
void setup()
{
Serial.begin(9600);
irrecv.enableIRIn(); // Start the receiver
}
void loop()
{
if (irrecv.decode(&results))
{
Serial.println(results.value);
irrecv.resume(); // Receive the next value
}
}
The serial monitor, doesn't show the circuit playground number when I send it.
Does somebody now how to read the number send by the circuit playground express?
I am developing an application for opendaylight Carbon where I need to know the MAC address of the switch. Can I determine this from the DpnId when the switch connects? Thanks.
Not sure which MAC you are referring to. If you are referring MAC address of each ofport of the DPN then you can register listener for FlowCapableNodeConnector model and you can get MAC by calling FlowCapableNodeConnector#getHardwareAddress in add method of listener. And if you are talking about VM/packet Source/destination MAC, then you first you need to punt the packet to controller and then you can use PacketProcessingListener and extract MAC as shown below.
public void onPacketReceived(PacketReceived notification) {
final short tableId = notification.getTableId().getValue();
final byte[] data = notification.getPayload();
Ethernet res = new Ethernet();
try {
res.deserialize(data, 0, data.length * NetUtils.NumBitsInAByte);
} catch (Exception e) {
LOG.warn("PacketInHandler: Failed to decode Packet ", e);
return;
}
try {
Packet pkt = res.getPayload();
LOG.info("Packet type is ->{}", pkt.getClass().getName());
if (pkt instanceof IPv4) {
IPv4 ipv4 = (IPv4) pkt;
byte[] srcMac = res.getSourceMACAddress();
byte[] dstMac = res.getDestinationMACAddress();
}
}
}
The DPID uniquely identifies the switch. The MAC address is generally not exposed.
Moreover, the switch itself generally does not have a MAC address
(they may have tens of MAC addresses for different functions/interfaces).
Switches work at a lower level, though, they work with MAC addresses.
i am new to this forum and the whole thing with Processing.
I have a specific question to ask and thanks a lot for your time and thoughts!
How can i connect my Arduino with Ethernet Shield, getting temperature values from a sensor so they can be seen to a processing script?
In a straight Arduino script, one gets the value, connects from the ethernet shield to a server and does what one likes. I have accomplished that.
In my case i want Arduino to just run the script of reading an analog input value from the sensor.
Is it possible?
I have made the serial connection work and read the values alright through the usb, but with ethernet shield? How can i get the value that arduino reads WITHOUT USB/Serial connection?
ps. i am using WAMP server etc, Windows 7
I am trying the UDP connection script example for both arduino and processing from http://arduino.cc/en/Tutorial/UDPSendReceiveString, but
1)i ain't sure if that's what i need,
2)i have excluded from firewall ports 6000, 8888 for my tests and have put the IP address of my Arduino at the Arduino script and "localhost" at the Processing script
THE CODE COPIED FOR BETTER USE HERE
/*
UDPSendReceive.pde:
This sketch receives UDP message strings, prints them to the serial port
and sends an "acknowledge" string back to the sender
A Processing sketch is included at the end of file that can be used to send
and received messages for testing with a computer.
created 21 Aug 2010
by Michael Margolis
This code is in the public domain.
*/
#include <SPI.h> // needed for Arduino versions later than 0018
#include <Ethernet.h>
#include <EthernetUdp.h> // UDP library from: bjoern#cs.stanford.edu 12/30/2008
// Enter a MAC address and IP address for your controller below.
// The IP address will be dependent on your local network:
byte mac[] = {
0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
IPAddress ip(192, 168, 1, 177);
unsigned int localPort = 8888; // local port to listen on
// buffers for receiving and sending data
char packetBuffer[UDP_TX_PACKET_MAX_SIZE]; //buffer to hold incoming packet,
char ReplyBuffer[] = "acknowledged"; // a string to send back
// An EthernetUDP instance to let us send and receive packets over UDP
EthernetUDP Udp;
void setup() {
// start the Ethernet and UDP:
Ethernet.begin(mac,ip);
Udp.begin(localPort);
Serial.begin(9600);
}
void loop() {
// if there's data available, read a packet
int packetSize = Udp.parsePacket();
if(packetSize)
{
Serial.print("Received packet of size ");
Serial.println(packetSize);
Serial.print("From ");
IPAddress remote = Udp.remoteIP();
for (int i =0; i < 4; i++)
{
Serial.print(remote[i], DEC);
if (i < 3)
{
Serial.print(".");
}
}
Serial.print(", port ");
Serial.println(Udp.remotePort());
// read the packet into packetBufffer
Udp.read(packetBuffer,UDP_TX_PACKET_MAX_SIZE);
Serial.println("Contents:");
Serial.println(packetBuffer);
// send a reply, to the IP address and port that sent us the packet we received
Udp.beginPacket(Udp.remoteIP(), Udp.remotePort());
Udp.write(ReplyBuffer);
Udp.endPacket();
}
delay(10);
}
/*
Processing sketch to run with this example
=====================================================
// Processing UDP example to send and receive string data from Arduino
// press any key to send the "Hello Arduino" message
*/
import hypermedia.net.*;
UDP udp; // define the UDP object
void setup() {
udp = new UDP( this, 6000 ); // create a new datagram connection on port 6000
//udp.log( true ); // <-- printout the connection activity
udp.listen( true ); // and wait for incoming message
}
void draw()
{
}
void keyPressed() {
String ip = "192.168.1.177"; // the remote IP address
int port = 8888; // the destination port
udp.send("Hello World", ip, port ); // the message to send
}
void receive( byte[] data ) { // <-- default handler
//void receive( byte[] data, String ip, int port ) { // <-- extended handler
for(int i=0; i < data.length; i++)
print(char(data[i]));
println();
}
Read those values into a file and use that file to send data to processing. http://py.processing.org/reference/createReader.html
Great scheme. Only one problem. It works perfectly on my system. I loaded my Arudino Uno R3 with your Arduino sketch and loaded the Processing sketch as well. Worked like a charm, first try. Didn't change anything on my Arduino, Windows system, Processing (2.0.3), network, etc.
Could be you have a Arduino board problem (unlikely) or an Ethernet shield problem (sadly, more likely). You could have a network problem (even more likely).
Try Wireshark. You will really just be guessing until you take a look at the Wireshark output. Note that Wireshark has filters. You will need them. Filter out all of the non-UDP traffic.
At the moment I have an Arduino board with an Ethernet Shield connected to a router. My computer connects to this router via Wi-Fi. My board and my computer send UDP messages back and forth to each other. My computer is a client, and the board is a server. However I noticed, that when I send a longer UDP message from my computer, and then a shorter UDP message, the Arduino accepts the shorter message, then followed by remaining bits from the longer message.
For instance: if I send "Hello World" from my computer, followed with "Test"; the Arduino will not read the second message as "Test", but rather: "Testo World".
I thought perhaps in was a problem from the Arduino end first. The Arduino stores the messages temporarily in an array called packetBuffer. I tried clearing this buffer before I receive a new message each time. The buffer would clear, but then I would receive the faulty message again.
So I assume the culprit is the computer, the client. On the computer end I have a processing sketch that sends the UDP messages. The example below is not the sketch itself; however it is by far a simpler example that still provides the exact symptoms as I described with my original sketch.
import hypermedia.net.*;
UDP udp; // define the UDP object
void setup() {
udp = new UDP( this, 6000 ); // Create a new datagram connection on port 6000
//udp.log( true ); // <-- printout the connection activity
udp.listen( true ); // and wait for incoming message
}
void keyPressed() {
String IPaddress = "192.168.1.177"; // The remote IP address
int port = 8888; // The destination port
if (keyCode == UP)
{
udp.send("Test", IPaddress, port );
}
else
if (keyCode == DOWN)
{
udp.send("Hello World", IPaddress, port );
}
}
void receive( byte[] data ) { // <-- default handler
//void receive( byte[] data, String IPaddress, int port ) { // <-- extended handler
for(int i=0; i < data.length; i++)
print(char(data[i]));
println();
}
How could I get the sketch to send the right messages?
Of course I am more than willing to provide more information.
There wasn't a direct solution to this problem; so I ended up resorting to a work around. The work around involves dynamically adding zeros to all strings sent to the Arduino so there is always 10 characters sent.
For instance:
If I am to send "Hello Bot", the actual string sent is "Hello Bot0". If I sent an additional message like "Test" after that, the string sent to the Arduino would be "Test000000". The additional zeros would cover up the overlapping characters. One problem with this work around is that I had to prepare the Arduino to accept the zeros also. This work around is also kind of messy for the code. It does work though.
Here's a snippet of code from the computer (client) side. The Arduino code obviously just had to be adjusted to account for the zeros.
public void Send() { //bang button named "Send" activates function
String txtSend = comField.getText(); //Grab text from a textbox to be sent
int txtSendLength = txtSend.length();
for(int i = 0; i < 10-txtSendLength; i++){ //Add zeros until it has 10 char
txtSend = txtSend + "0";
}
udp.send(txtSend, ip, port);
comField.clear(); //Clear the textbox
}
Behold, the very simple and crude solution!
I believe your issue is with properly clearing the buffer. I found a line of code that goes through and clears each character, since it is a character array. There is theoretically no buffer to clear once it is read.
Use:
for(int i=0;i<UDP_TX_PACKET_MAX_SIZE;i++) packetBuffer[i] = 0;
Once you read the data, and that will clear the array. I also found out that when trying to do logic on the data that was received, in order to control some output, I needed to first convert the packetBuffer to a string. After that, all seemed to work correctly.
Hope that help.