swimtracker-firmware/firmware.ino

#include "HX711.h"
#include <ESP8266WiFi.h>
#include <WiFiUdp.h> // for NTP
#include <NTPClient.h> // for NTP
#include <ESP8266WebServer.h>
#include <FS.h>

#include "config.h"


int16_t compressMeasurement(int32_t value) {
    return (int16_t)(measurement / DIVIDER)
}



HX711 scale;
WiFiUDP ntpUDP;
NTPClient timeClient(ntpUDP, "pool.ntp.org");
TrainingSession session;
ESP8266WebServer webServer(80);

bool makeMeasurement(long & measurementOut)
{
    if (scale.is_ready())
    {
        measurementOut = scale.get_value(MEASUREMENT_AVG_COUNT);
        return true;
    }
    else
        return false;
}


void setup()
{
    digitalWrite(LED_PIN, HIGH);

    // Serial
    Serial.begin(115200);
    while(!Serial) {}

    // wifi
    WiFi.mode(WIFI_STA);
    WiFi.hostname(HOSTNAME);
    WiFi.begin(WIFI_SSID, WIFI_PASSWD);

    Serial.print(F("\n\n"));
    Serial.println(F("Waiting for WIFI connection..."));
    while (WiFi.status() != WL_CONNECTED) {
        delay(1000);
    }

    Serial.print(F("Connected to WiFi. IP:"));
    Serial.println(WiFi.localIP());

    timeClient.begin();
    timeClient.update();

    // initialize cell
    scale.begin(LOADCELL_DOUT_PIN, LOADCELL_SCK_PIN);
    scale.tare( TARE_AVG_COUNT );

    // NTP
    session.init( &timeClient );
    Serial.print("Initialized NTP client: ");
    Serial.println(timeClient.getEpochTime());

    // webserver
    webServer.on("/api/session", [] () {
        session.send(&webServer);
    });
    webServer.on("/api/save", [] () {
        webServer.send(200, "text/plain", session.saveToFileSystem());
    });
    webServer.on("/api/tare", [] () {
        scale.tare( TARE_AVG_COUNT );
        webServer.send(200, "text/plain", "OK");
    });
    webServer.on("/", HTTP_GET, [](){
        Serial.println("index.html requested");
        File file = SPIFFS.open("/index.html", "r");
        size_t sent = webServer.streamFile(file, "text/html");
        file.close();
    });
    webServer.on("/swimtrainer.webmanifest", HTTP_GET, [](){
        File file = SPIFFS.open("/swimtrainer.webmanifest", "r");
        size_t sent = webServer.streamFile(file, "application/manifest+json");
        file.close();
    });



    webServer.begin();
    Serial.println("Webserver started");

    // flash file system
    if(!SPIFFS.begin()){
        Serial.println("An Error has occurred while mounting SPIFFS");
    }
}


void loop()
{
    const long cycleStart = millis();


    digitalWrite(LED_PIN, HIGH);


    long measurement = 0;
    if(makeMeasurement(measurement))
    {
        session.addPoint(measurement);
    } else {
        Serial.println("Measurement skipped - cell not ready");
    }

    webServer.handleClient();

    const long cycleDuration = millis() - cycleStart;
    if( cycleDuration <= DELAY)
    {
        delay(DELAY - cycleDuration);
    }
    else
    {
        Serial.print("Skipping measurement, cycle duration was ");
        Serial.println(cycleDuration);
        const long skipped = (cycleDuration / DELAY);
        //for(int i=0; i < skipped; ++i)
        //  session.addPoint(0xFFFFFFFE);

        delay(DELAY * (skipped + 1) - cycleDuration);
    }

}