diff --git a/src/sensors/HallSensor.cpp b/src/sensors/HallSensor.cpp
index 6c2367ff..7d1d9f64 100644
--- a/src/sensors/HallSensor.cpp
+++ b/src/sensors/HallSensor.cpp
@@ -113,10 +113,11 @@ float HallSensor::getMechanicalAngle() {
   function using mixed time and frequency measurement technique
 */
 float HallSensor::getVelocity(){
-  if (pulse_diff == 0 || ((long)(_micros() - pulse_timestamp) > pulse_diff) ) { // last velocity isn't accurate if too old
+  long last_pulse_diff = pulse_diff;
+  if (last_pulse_diff == 0 || ((long)(_micros() - pulse_timestamp) > last_pulse_diff) ) { // last velocity isn't accurate if too old
     return 0;
   } else {
-    float vel = direction * (_2PI / (float)cpr) / (pulse_diff / 1000000.0f);
+    float vel = direction * (_2PI / (float)cpr) / (last_pulse_diff / 1000000.0f);
     // quick fix https://github.com/simplefoc/Arduino-FOC/issues/192
     if(vel < -velocity_max || vel > velocity_max)  vel = 0.0f;   //if velocity is out of range then make it zero
     return vel;