float voltage=50.2;
float current=0;

void setup() {
  pinMode(LED_BUILTIN, OUTPUT);
  Serial.begin(115200);
}

void loop() {
  digitalWrite(LED_BUILTIN,!digitalRead(LED_BUILTIN));
  voltage=constrain(voltage+random(-10,11)/100.0, 10*3.3,12*4.2);
  current=constrain(current+random(-40,41)/10.0, 0,50);
  
  Serial.write((uint8_t *) &voltage, sizeof(voltage));//float 4bytes
  Serial.write((uint8_t *) &current, sizeof(voltage));//float 4bytes 
  delay(20);
}