private void OnSensor() { if (chMonitor.Checked) { DrawingObjects.DrawOnSensor(graphics); } pnLed.BackColor = Color.BlueViolet; deltaTime = micros() - lastTime; lastTime = micros(); sensor = 1; if (deltaTime > 0) { monRPM.Text = Convert.ToString(Convert.ToInt32(60000000M / deltaTime)) + " rpm"; } }