Hi.
I am using my Arduino for remote measurements via ethernet. I send an HTTP request to the Arduino and get a response with the specified measurement value. This works for standard measurements that the Arduino can do by itself, like Voltage. I am however experiencing a weird problem when using the Adafruit INA219 I2C chip to measure current.
When a request for current measurement is made, the Arduino communicates with the INA219 as it should and responds via http, but it hangs in the first new cycle of the main loop after the completed response. The system no longer listens for http requests and requires a physical restart before it stars functioning again.
I am running an Arduino Meag2560 R3 with the Arduino Ethernet shield 2. Communicating with the Adafruit INA219 by I2C.
for specs on the INA219 see INA219 High Side DC Current Sensor Breakout - 26V ±3.2A Max [STEMMA QT] : ID 904 : $9.95 : Adafruit Industries, Unique & fun DIY electronics and kits
#include <Adafruit_INA219.h>
#include <CommandList.h>
#include <Ethernet.h>
int count=0;
byte mac[] = { 0xA8, 0x61, 0x0A, 0xAE, 0xA9, 0xB9 };
EthernetServer server(80);
boolean httpActive=false;
void setup() {
Serial.begin(9600);
Serial.setTimeout(100);
digitalWrite(4, HIGH); //deselect SD card mode
Ethernet.init(10); //init ethernet
Ethernet.begin(mac); //Initiate connection using DHCP
server.begin( );
Serial.println(Ethernet.localIP());
}
void loop() {
count++;
if(count==2000){
Serial.println("Still running"); //For debugging
count=0;
}
int res;
readCommand();
if(httpActive){
Serial.println("currentMeasurement");
res=intCurrent();
Serial.println(res);
sendResponse(res);
}
Serial.println(F("Returned to loop"));
}
//--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
//Measure current. Private function.
//--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
int currentMeasure(Adafruit_INA219 *ina219){
return (ina219)->getCurrent_mA();
}
//--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
//Function for current measurement.
//--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
int intCurrent(){
int moduleAdr=0x40; //I2C address current sensor
Adafruit_INA219 ina219(moduleAdr);
if(!ina219.begin()){ //if not connected, send error
Serial.println(F("Failed to find INA219 chip"));
return 0;
}
int reading=currentMeasure(&ina219); //Single reading
//Terminate connection, reset settings.
ina219.~Adafruit_INA219();
if(ina219.success())Serial.println("destructed INA219");
return reading;
}
//--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
//Send a response via http
//--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
void sendResponse(int value){
Serial.println(F("Send response function"));
EthernetClient client = server.available();
if (client) {
Serial.println(F("client found"));
while (client.connected()){
Serial.println(F("client connected"));
if (client.available()){
Serial.println(F("client available"));
client.println ("HTTP/1.1 200 OK");
client.println ("Content-Type: text/html");
client.println ("Connection: close");
client.println ( );
client.println ("Brewing Coffe :)");
client.print(value);
client.flush();
Serial.println(F("actually sent"));
break;
}
}
delay(1);
client.stop();
Serial.println(F("client stopped"));
}
Serial.println(F("Function end"));
httpActive=false;
return;
}
//--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
//Read http command from ethernet shield
//--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
void readCommand(){
Serial.println(F("Read command func"));
String commandStr="";
EthernetClient client = server.available();
if(client){
if(client.available()){
boolean currentLineIsBlank = true;
char character = client.read ( );
while(!(character == '\n' && currentLineIsBlank)){
Serial.write(character);
commandStr+=character;
character = client.read ( );
if ( character == '\n') {
currentLineIsBlank = true;
}else if (character != '\r') {
currentLineIsBlank = false;
}
}
}
}
Serial.println(F("client finished"));
if(commandStr.indexOf("favicon")!=-1){
Serial.println(F("Favicon stopped"));
client.stop();
return;
}else if(commandStr!=""){
Serial.println(F("Non empty command"));
httpActive=true;
return;
}
Serial.println(F("empty command"));//<------------- crashes here
return;
}
As mentioned this issue only happens after a call to the INA219 chip, so I believe the problem is connected to I2C communication. Is there possibly a memory overlap in the Adafruit library and the Ethernet library?
When running the freeRam() function ( Solved: Use of freeRAM() ) in my main code during debugging I have found that there are approximately 6000 bytes still available, so I don't believe that I am running out of memory.
I am grateful for any help and insight you are able to give.
PS: This is my first post on the forum. If I have made any mistakes when posting, i.e. incorrect use of code tags or links, please let me know so I can fix my mistakes.
