I'm trying to make a python client communicate with an arduino server. The python client asks the server to take a measurement from the sonar, and then server just sends a confirmation message and then takes the message.
The client:
client.py
import socket
import time
while True:
try:
client_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
client_socket.connect(("192.168.0.250", 10220))
data = "GET\nSONAR\n\n"
print 'send to server: ' + data
client_socket.send(data)
receive = client_socket.recv(2048)
print receive
client_socket.close()
time.sleep(0.1)
except Exception as msg:
print msg
and the server:
server.ino
#include <avr/wdt.h>
#include <SPI.h>
#include <Ethernet.h>
#include <SoftwareSerial.h>
//localClient parameters, for sending data to the server.
byte mac[] = {0x90, 0xA2, 0xDA, 0x0F, 0x03, 0x58};
byte ip[] = {192,168,0,250};
byte server[] = {192, 168, 0, 100};
int serverPort = 8220;
//Server parameters, for acting like a server.
int pollPort = serverPort + 2000;
EthernetServer pollServer = EthernetServer(pollPort);
//char inString[32]; // string for incoming serial data
//sonar stuff
String content_string;
int NUM_SONARS = 1;
int sonarPin[] = {2, 3, 4, 5};
int triggerPin = 6;
int sonarThreshold = 12.0;
int sonarState[] = {0, 0, 0, 0};
long pulse;
int numPulses = 3;
int pulseArray[] = {0,0,0,0,0};
int filteredMode = 0;
float time;
void setup() {
Serial.begin(9600);
Ethernet.begin(mac, ip);
wdt_enable(WDTO_8S);
pollServer.begin();
for(int i = 0; i < NUM_SONARS; i++) {
pinMode(sonarPin[i], INPUT);
}
pinMode(triggerPin, OUTPUT);
digitalWrite(triggerPin, LOW);
time = 0;
}
void loop() {
wdt_reset();
time = millis();
EthernetClient pollClient = pollServer.available();
if (pollClient) {
boolean currentLineIsBlank = true;
String receivingString = "";
while (pollClient.connected()) {
//while the socket is open
if(pollClient.available()) {
//and there is something to read on the port, then read the available characters
char c = pollClient.read();
receivingString += c;
if (c == '\n' && currentLineIsBlank) {
Serial.print("String received -- ");
Serial.print(receivingString);
Serial.print("at ");
Serial.println(time);
pollClient.println("Received message.");
break;
}
if (c == '\n') {
// you're starting a new line
currentLineIsBlank = true;
}
else if (c != '\r') {
// you've gotten a character on the current line
currentLineIsBlank = false;
}
}
}
// give the web browser time to receive the data
delay(1);
// parse the incoming data
String command = split(receivingString,'\n',0);
String payload = split(receivingString,'\n',1);
String key = split(payload,'=',0);
String value = split(payload,'=',1);
//PARSE THE KEY AND VALUE NOW
if(command == "GET") {
//if I received a GET command, send a response to the client.
if(key == "SONAR") {
pingSonars();
}
}
}
String split(String data, char delimiter, int index) {
int found = 0;
int strIndex[] = {0, -1};
int maxIndex = data.length()-1;
for(int i=0; i<=maxIndex && found<=index; i++){
if(data.charAt(i)==delimiter || i==maxIndex){
found++;
strIndex[0] = strIndex[1]+1;
strIndex[1] = (i == maxIndex) ? i+1 : i;
}
}
return found>index ? data.substring(strIndex[0], strIndex[1]) : "";
}
void isort(int *a, int n) {
for (int i = 1; i < n; ++i) {
int j = a[i];
int k;
for (k = i - 1; (k >= 0) && (j < a[k]); k--) {
a[k + 1] = a[k];
}
a[k + 1] = j;
}
}
int mode(int *x,int n){
int i = 0;
int count = 0;
int maxCount = 0;
int mode = 0;
int bimodal;
int prevCount = 0;
while(i<(n-1)){
prevCount=count;
count=0;
while(x[i]==x[i+1]){
count++;
i++;
}
if(count>prevCount&count>maxCount){
mode=x[i];
maxCount=count;
bimodal=0;
}
if(count==0){
i++;
}
if(count==maxCount){//If the dataset has 2 or more modes.
bimodal=1;
}
if(mode==0||bimodal==1){//Return the median if there is no mode.
mode=x[(n/2)];
}
return mode;
}
}
void printArray(int *a, int n) {
for (int i = 0; i < n; i++)
{
Serial.print(a[i], DEC);
Serial.print(' ');
}
Serial.println();
}
void pingSonars() {
digitalWrite(6, HIGH);
for(int i = 0; i < NUM_SONARS; i++) {
for(int j = 0; j < numPulses; j++) {
pulse = pulseIn(sonarPin[i], HIGH);
pulseArray[j] = pulse/147; //convert to inches -- 147 uS per inches
delay(5);
}
isort(pulseArray, numPulses);
filteredMode = mode(pulseArray,numPulses);
//printArray(pulseArray,numPulses);
Serial.print("Filtered distance for Sonar ");
Serial.print(i);
Serial.print(": ");
Serial.println(filteredMode);
if((filteredMode < sonarThreshold) && !sonarState[i]) {
//if we are closer than the threshold and previously were not, this is a rising edge:
Serial.print("Sonar ");
Serial.print(i);
Serial.println(" triggered!");
sonarState[i] = 1;
}
else if (filteredMode > sonarThreshold && sonarState[i]) {
//if we are greater than the threshold and previously were, this is a falling edge:
Serial.print("Sonar ");
Serial.print(i);
Serial.println(" falling!");
sonarState[i] = 0;
}
}
}
The client sends requests at about a 100 millisecond interval, but the server seems to be able to respond much slower than that -- maybe at 2-3 times per second. What's limiting the rate of communication? Is it possible that the serial printouts are actually limiting it? Or does it have to do with how I'm opening/closing/listening to the port in the server code?
thanks for your help!