I am writing an Arduino program to control two servos on a catapult via Blynk using Bluetooth serial communication. I have two widgets on my Blynk application; the first widget consists of two buttons: 'Arm' which will lock the catapult arm into place and tension it and 'Launch' which will release the lock servo and release the tension from the catapult arm (which is assigned to virtual pin V0), as well as a second Bluetooth widget that will allow me to pair my Android device with an HC-05 Bluetooth Module. My hardware is already set up, so now I am just trying to figure things out on the software end. I uploaded my program to the Arduino and paired my Blynk application with the Bluetooth Module, and they were successfully paired (indicated by a blinking light every 2 seconds), but my Blynk button input to the Arduino was met with no response from the servos. I checked my jumper wire connections to and from the Bluetooth Module and they were all correct (VCC to 5V, GND to GND, RX to RX, and TX to TX), so unless I am supposed to connect the RX to TX and the TX to RX, I believe my problem lies within my program. Am I following the correct structure in my program to store button input or should the BLYNK_WRITE() code be placed inside my loop?
#include <SoftwareSerial.h>
#include <BlynkSimpleSerialBLE.h>
#include <Servo.h>
// You should get Auth Token in the Blynk App.
// Go to the Project Settings (nut icon).
char auth[] = "***";
SoftwareSerial SerialBLE(2, 4); // RX, TX
Servo lock_servo;
Servo tension_servo;
// Write Blynk button state to virtual pin and store parameter as integer
BLYNK_WRITE(V0) {
// if button state is equal to 1 (arm button pressed)
if(param.asInt() == 1) {
// set the angle of the lock servo to 90 degrees
lock_servo.write(90);
// set the angle of the tension servo to 180 degrees
tension_servo.write(180);
Blynk.notify("The catapault is armed and ready to launch!");
}
// if button state is equal to 2 (launch button pressed)
else {
// set the angle of the lock servo to 0 degrees
lock_servo.write(0);
delay(1000);
// set the angle of the tension servo to 0 degrees
tension_servo.write(0);
Blynk.notify("A launch has occurred, re-arm is required!");
}
// Check to see if button state is repeating or done
Blynk.syncVirtual(V0);
}
// setup code which will only run once
void setup() {
// estabilish Bluetooth serial connection with baud rate of 38400
SerialBLE.begin(38400);
Blynk.begin(SerialBLE, auth);
// attach a pin as a servo driver for lock and tension servos
lock_servo.attach(10);
tension_servo.attach(11);
}
// main code which will be ran repeatedly
void loop() {
Blynk.run();
}
