Reed Switch Bike Speedometer using Particle Argons

int button = D1;     //input button is connected to D1 and the other terminal to ground.
int groundpin = D0;  // aux ground out.
int switchstate = 0; //a variable that will hold the current switch state
int lastswitchstate = 0; // a variable that will hold the previous switch state
const pin_t MY_LED = D7;
String Speed;        //declare speed value.
char publishString[40];
float rssival = 0;
float rssipct = 0;
//volatile bool mailsend = FALSE; //not needed
volatile bool rssisend = FALSE;

//Thingspeak key
const String key = "ME8J3G47QWK87YEP";

// fuction for subcribe, this will update speed
void myHandler(const char *event, const char *data){
 //print passed speed value to realterm (for testing purpose)
 Serial.println(event);
  Serial.print("(from Argon1): ");
 Serial.println(data);
 //sets subscribed Speed sata to local as Speed variable
 Speed=data;
//will Flash D7 LED to let know Speed was Updated
 digitalWrite(MY_LED, HIGH);
    delay(1s);
    digitalWrite(MY_LED, LOW);
 
}

void setup(){
    //set up D7 led
        pinMode(MY_LED, OUTPUT);
        //update Speed value
        Particle.subscribe("Speed", myHandler, MY_DEVICES);
        
        Serial.begin(9600);
        //set up for button
        pinMode(button, INPUT_PULLUP);
        pinMode(groundpin, OUTPUT);
      
        rssisend = TRUE; //for web hook
 }

void loop() {
     
    lastswitchstate = switchstate;  //copy the previous switch state to the last switch state
    switchstate = digitalRead(D1);  //read a new switch state.
    if (lastswitchstate == 0 && (switchstate == 1)) { //if both are true then...  This is a bit more advanced than just detecting a input state. It detects an edge of a signal to prevent overloading the cloud.
        //"==" compares the two values.  If equal it takes a value of "true" or 1.
       // Particle.publish("data-start/stop", String(Speed), PRIVATE);  //send the event to the particle cloud
       // delay(2000);
       
       // Particle.subscribe("data-start/stop", string(Speed), PRIVATE);
       
        rssi_update();//run the update function
       // Serial.print();
        
    }
}

void rssi_update(){
    
    //delay (2000);
    static int count = 0;
    Serial.println(count++);
    //rssival = WiFi.RSSI();  //measure RSSI
    WiFiSignal sig = WiFi.RSSI();
    rssival = sig.getStrengthValue();
    rssipct = sig.getStrength();

    sprintf(publishString, "%d", rssival);

    //sprintf(publishString,"%d",strength);
    //bool success = Particle.publish("RSSI",publishString);
    bool success = Particle.publish("RSSI", String(rssival));
    
    Particle.publish("thingSpeakWrite_All", +
        "{ \"1\": \"" + String(rssival) + "\"," +
        "\"2\": \"" + String(Speed) + "\"," +
        "\"3\": \"" + String(Speed) + "\"," +
        "\"5\": \"" + String(Speed) + "\"," +  //channel 5 due to a legacy SOC channel being calculated on thingspeak via a react.
        //"\"5\": \"" + String(var4) + "\"," +
        "\"k\": \"" + key + "\" }", 60, PRIVATE, WITH_ACK);


    if (success == TRUE) {
        //delay(10000);
        rssisend = FALSE;                        //if sent, then turn of the send flag, otherwise let it try again.
    }
}