Hello!
I am using the vl53l1x on a raspberry pi with python (pimoroni library) and want to implement the NON-BLOCKING communication
So I changed the “wait_method” in the api (vl53l1_api_core.c) for measurements to NON_BLOCKING and recompiled/reinstalled the module with the following funtion to get the distance from the sensor:
int32_t getDistance(VL53L1_Dev_t *dev)
{
VL53L1_Error Status = VL53L1_ERROR_NONE;
int32_t current_distance = -1;
uint8_t dataready = 0;
Status = VL53L1_GetMeasurementDataReady(dev, &dataready); *// VL53L1_GetMeasurementDataReady takes a pointer, so we pass the address of dataready*
if (dataready == 1)
{
Status = VL53L1_GetRangingMeasurementData(dev, pRangingMeasurementData);
current_distance = pRangingMeasurementData->RangeMilliMeter;
VL53L1_ClearInterruptAndStartMeasurement(dev);
}
return current_distance;
}
However, using the following code in Python, the result is still a blocking/waiting communication for when data is ready (dataready=1). I used the following code and printed out the time spent for the get_distance() function. As you can see, it is 1 ms for when data is not ready and about 30 ms for when data is ready (tried it with different timing budgets and periods, but same effect of 30 ms waiting)
The Python code for the picture:
tof.set_timing(30000, 40)
print("budget", tof.get_timing())
time.sleep(0.5)
while running:
elapsed = 0
current_time = time.time()
time_before = time.time()
distance_in_mm = tof.get_distance() # Grab the range in mm
print("time spend", time.time()-time_before) # print the time spent **for** grabbing the range
if distance_in_mm>0:
print("Distance: {}mm".format(distance_in_mm))
while elapsed < 0.05: [#wait](javascript:void(0);) to complete the 50 ms cycle
elapsed = time.time()-current_time
print("50 ms loop done"+"\n")
