{
RPM = analogRead(TacSig); // read the value from the sensor
Serial.println(RPM); // print the value to the serial port
}
{buttonstatestart = digitalRead(buttonstart); }
{buttonstateoff = digitalRead(buttonoff); }
What's with all the extra curly braces? This section of code does not need any curly braces.
if (buttonstatestart == HIGH)
{
digitalWrite(start, HIGH);
digitalWrite(acc, LOW);
digitalWrite(run, HIGH);
}
Every time through loop that the button state is HIGH, it will execute this code. That is NOT what you want. You only want to execute this code when the state is HIGH now and was not HIGH last time.