Improve library latency by removing unnecessary delays and flushing the buffer

Author: carrascoacd

Http.cpp

@@ -134,7 +134,6 @@ Result HTTP::post(const char *uri, const char *body, char *response) {
   }
 
   purgeSerial();
-  delay(500);
   sendCmd(body);
 
   if (sendCmdAndWaitForResp(HTTP_POST, HTTP_2XX, delayToDownload) == TRUE) {

HttpExample/WeatherStationExample.ino

@@ -1,100 +1,130 @@
-#include <LowPower.h>
+
 #include <ArduinoJson.h>
 #include <Http.h>
+#include <DHT.h>
+#include <Battery.h>
+//#include <NewPing.h>
 
-unsigned long lastRunTime = 0;
-unsigned long waitForRunTime = 0;
-unsigned long millisOffset = 0;
-unsigned int RX_PIN = 11;
-unsigned int TX_PIN = 12;
-unsigned int RST_PIN = 10;
-HTTP http(9600, RX_PIN, TX_PIN, RST_PIN, true);
-
-/*
- * the setup routine runs once when you press reset:
- */
-void setup() {
-  Serial.begin(9600);
-  while(!Serial);
-  Serial.println("Starting!");
-}
+//#define TRIGGER_PIN 5
+//#define ECHO_PIN 6
+//#define MAX_DISTANCE 100
+#define RX_PIN 11
+#define TX_PIN 12
+#define RST_PIN 10
+#define MOISTURE_PIN 7
+#define TEMPERATURE_HUMIDITY_PIN 13
+#define DHTTYPE DHT11
+#define OPEN_VALVE_PIN 5
+#define LIPO_BATTERY_PIN 5
+#define LITIO_BATTERY_PIN 6
+#define ENDPOINT "https://your-endpoint"
+#define BODY_FORMAT "{\"w\":{\"m\": %d, \"t\": %d, \"h\": %d, \"mv\": %d, \"sv\": %d}}"
+//#define BEARER "gprs-service.com"
+//#define BEARER "movistar.es"
+#define BEARER "gprs-service.com"
+#define DEBUG 0
 
-/*
- * the loop routine runs over and over again forever:
- */
-void loop() {
-  if (shouldTrackTimeEntry()){
-    http.wakeUp();
-    trackTimeEntry();
-  }
-  else {
-    http.sleep();
-  }
-}
+unsigned long waitForRunTime = 1;
+const HTTP http(9600, RX_PIN, TX_PIN, RST_PIN, DEBUG);
+const DHT dht(TEMPERATURE_HUMIDITY_PIN, DHTTYPE);
+Battery liPoBattery(3300, 3800, LIPO_BATTERY_PIN);
+Battery litioBattery(3300, 3800, LITIO_BATTERY_PIN);
+//const NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE);
 
 /*
  * functions
  */
-void print(const __FlashStringHelper *message, int code = -1){
-  if (code != -1){
-    Serial.print(message);
-    Serial.println(code);
-  }
-  else {
-    Serial.println(message);
-  }
-}
 
-unsigned long currentMillis(){
-  return millis() + millisOffset;
+void openValveFor(unsigned long milliseconds){
+  Serial.print(F("Open valve for: "));
+  Serial.println(milliseconds);
+  digitalWrite(OPEN_VALVE_PIN, LOW);
+  delay(10000 + milliseconds);
+  Serial.println(F("Close Valve"));
+  digitalWrite(OPEN_VALVE_PIN, HIGH);
 }
 
-void sleepEightSeconds(){
-  LowPower.powerDown(SLEEP_8S, ADC_OFF, BOD_OFF);
-  /* The 8000 is 8 seconds, the time the clock has been sleeping */
-  millisOffset += 8000;
-}
-
-bool shouldTrackTimeEntry(){
-  /*
-   * This calculation uses the max value the unsigned long can store as key. Remember when a negative number 
-   * is assigned or the maximun is exceeded, then the module is applied to that value.
-   */ 
-  sleepEightSeconds();
-  unsigned long elapsedTime = currentMillis() - lastRunTime;
-  print(F("Elapsed time: "), elapsedTime);
-  return elapsedTime >= waitForRunTime;
+unsigned int readMoisture() {
+  unsigned long total = 0;
+  for (unsigned int i=0; i<100; ++i){
+    total += analogRead(MOISTURE_PIN);
+  }
+  return total/100;
 }
 
-void trackTimeEntry(){
+void manageGarden(){
+  int humidity = dht.readHumidity();
+  Serial.print(F("Humidity % "));
+  Serial.println(humidity);
+  int temperature = dht.readTemperature();
+  Serial.print(F("Temperature "));
+  Serial.println(temperature);
+  unsigned int moisture = readMoisture();
+  Serial.print(F("Moisture "));
+  Serial.println(moisture);
+  unsigned int litioBatteryVoltage = litioBattery.voltage();
+  Serial.print(F("Litio voltage "));
+  Serial.println(litioBatteryVoltage);
+  unsigned int liPoBatteryVoltage = liPoBattery.voltage();
+  Serial.print(F("LiPo voltage "));
+  Serial.println(liPoBatteryVoltage);
+  //Serial.print(F("Water tank distance cm: "));
+  //float distance = sonar.ping_cm();
+  //Serial.println(distance);
 
   char response[32];
   char body[90];
   Result result;
+  sprintf(body, BODY_FORMAT, moisture, temperature, humidity, litioBatteryVoltage, liPoBatteryVoltage);
+  Serial.println(body);
 
-  print(F("Cofigure bearer: "), http.configureBearer("your.apn"));
-  result = http.connect();
-  print(F("HTTP connect: "), result);
-
-  unsigned int moisture = random(1023);
-  char voltage[6];
-  http.readVoltage(voltage);
 
-  sprintf(body, "[{\"weatherEntry\":[{\"m\": %d, \"cv\": %s}], \"n\": \"Arduino\"}]", moisture, voltage);
-  Serial.println(body);
+  http.configureBearer(BEARER);
+  result = http.connect();
+  result = http.post(ENDPOINT, body, response);
+  http.disconnect();
 
-  result = http.post("your.api", body, response);
-  print(F("HTTP POST: "), result);
   if (result == SUCCESS) {
     Serial.println(response);
     StaticJsonBuffer<32> jsonBuffer;
     JsonObject& root = jsonBuffer.parseObject(response);
-    lastRunTime = currentMillis();
-    waitForRunTime = root["waitForRunTime"];
 
-    print(F("Last run time: "), lastRunTime);
-    print(F("Next post in: "), waitForRunTime);
+    if (strcmp(root["action"], "open-valve") == 0){
+      openValveFor(root["value"]);
+      // Delay 1 minute to overpass the irrigation time
+      delay(60000);
+    }
+    else {
+      delay(root["value"]);
+    }
+  }
+}
+
+/*
+ * the setup routine runs once when you press reset:
+ */
+void setup() {
+  if (DEBUG){
+    Serial.begin(9600);
+    while(!Serial);
+    Serial.println(F("Starting!"));
   }
 
-  print(F("HTTP disconnect: "), http.disconnect());
-}
+  pinMode(MOISTURE_PIN, INPUT);
+  pinMode(OPEN_VALVE_PIN, OUTPUT);
+  pinMode(OPEN_VALVE_PIN, HIGH);
+  
+  openValveFor(1000);
+  dht.begin();
+  liPoBattery.begin(5000, 1.0);
+  litioBattery.begin(5000, 1.0);
+}
+
+/*
+ * the loop routine runs over and over again forever:
+ */
+void loop() {
+  http.wakeUp();
+  manageGarden();
+  http.sleep();
+}

Sim800.cpp

@@ -40,6 +40,7 @@ int SIM800::preInit(void)
     delay(3000);
 
     purgeSerial();
+    serialSIM800.flush();
 
     return TRUE;
 }
@@ -68,7 +69,7 @@ int SIM800::readBuffer(char *buffer, int count, unsigned int timeOut)
             break;
         }
     }
-    delay(500);
+
     while(serialSIM800.available()) {
         serialSIM800.read();
     }
@@ -85,7 +86,10 @@ void SIM800::cleanBuffer(char *buffer, int count)
 void SIM800::sendCmd(const char* cmd)
 {
     serialSIM800.listen();
+    serialSIM800.flush();
+    delay(500);
     serialSIM800.write(cmd);
+    serialSIM800.flush();
 }
 
 int SIM800::sendATTest(void)
@@ -128,7 +132,6 @@ void SIM800::sendEndMark(void)
 
 int SIM800::sendCmdAndWaitForResp(const char* cmd, const char *resp, unsigned timeout)
 {
-    delay(1000);
     sendCmd(cmd);
     return waitForResp(resp,timeout);
 }