Time of Flight (ToF) User Manual

The Time of Flight (ToF) sensor uses 940mm Laser VCSEL for fast and accurate measurement of distance to elements located in front of it.

By default, the sensor is setup with:

  • High accuracy mode, calibrated and ready to use.
  • Measurement of the distance has a sample rate of 10 minutes
  • Measurement of temperature and humidity has a sample rate of 15 hours.

Note: The first measurement of the ToF distance, temperature and humidity will always be 0 (zero).

 

Configure LoRa's Sensor For Long Range Mode

Important: This section only support Time of Flight sensors with PN: 1101149, Time of Flight, Temperature and Humidity.

You can set the sensor to long range mode by running this OTA via LoRaWAN Downlink:

Schedule First
FPort 2
Payload (bytes)

FA 01 00 00 05 91 00 00 03 02 99 00 00 02 08 9A 03 01 09 0C 9B 00 00 00 FF A9 00 00 00 FF CE
Confirmed IMPORTANT: Set it to NO (FALSE)

Example (see image below) on how to push payload to your device with The Things Network (TTN). Once the device receives the payload, it will patch itself and reboot. Because of the reboot cycle, the device won't be able to send acknowledge / confirmation that payload has been received. It's important you unchecked option "Confirmed".

downlink
Example with The Things Network (TTN)

 

Switch back to High Accuracy Mode

Follow the procedure described in "Configure LoRa's Sensor For Long Range Mode" and replace the payload with:

FA 01 00 00 05 91 00 00 03 02 99 00 00 02 08 9A 03 01 09 0A 9B 00 00 00 FF A9 00 00 00 FF CE

 


Max ranging distance

Target reflectance level Conditions Indoor (2) Outdoor overcast (2)
White target (88%)

Typical


Minimum

200 cm+ (1)


120 cm

80 cm


60 cm

Grey target (17%)

Typical


Minimum

80 cm


70 cm

50 cm


40 cm

Note (1): using long range
Note (2):

  • Indoor: no infrared
  • Outdoor overcast corresponds to a parasitic noise of 10k cps/SPAD for VL53L0X. For reference, this corresponds to a 1.2W/m² at 940nm, and is equivalent
    to 5k Lux daylight, while ranging on a grey 17% chart at 40cm

Measurement conditions:

  • Targets reflectance used : Grey (17%), White (88%)
  • Temperature (23°C)
  • All distances are for a complete Field of View covered (FOV = 25degrees)

All distances mentioned in this table are guaranteed for a minimum detection rate of 94% (up to 100%). Detection rate is the worst case percentage of measurements that will return a valid measurement when target is detected.

Ranging accuracy

  Indoor (no infrared) Outdoor
Target reflectance level (full FOV) Distance 33 ms 66 ms Distance 33 ms 66 ms
White Target (88%) At 120 cm 4% 3% At 60 cm

7%

6%
Grey Target (17%|) At 70 cm 7% 6% At 40 cm

12%

9%

Measurement conditions:

  • Targets reflectance used: Grey (17%), White (88%)
  • Offset correction done at 10 cm from sensor
  • Indoor: no infrared / Outdoor: eq. 5 kLux equivalent sunlight (10 kcps/SPAD)
  • Temperature (23°C)
  • All distances are for a complete FOV covered (FOV = 25 degrees)
  • Detection rate is considered at 94% minimum

Status Code

Code Description
0 Range valid
1 Sigma fail (too much ambient light)
2 Signal failed (return signal low)
3 Min Range failed
4 Phase fail (phase wraparound, noise)
5 Hardware fail

 

Measurement Range vs Actual Distance (Default High Accuracy)
Measurement Range vs Actual Distance (Default High Accuracy)
​​​​​​

 

Long range
Measurement Range vs Actual Distance (Long range)