Manufacturing / Level Sensing
ToF tank level monitor: Non-contact level sensing with the VL53L0X and LoRa, BLE or Wi-Fi
For an Indian industrial client we built a non-contact tank level monitor on the VL53L0X time-of-flight sensor, with LoRa, BLE or Wi-Fi telemetry and refill alerts. Completed by early 2025; >1 year on battery is the design target.
What we did: We designed the low-power embedded system around the VL53L0X time-of-flight sensor, cover-window crosstalk calibration and outlier filtering for condensation and dust, wireless telemetry over LoRa, BLE or Wi-Fi, a cloud dashboard with alerts, mobile notifications, and an output that can start a refill pump when the level drops below a threshold.
Industrial client, India6 months
Status: Completed (case study first published February 2025)
Published Last reviewed:
Illustrative imageThe challenge
Common tank level sensors each have a weak point: floats wear out mechanically, and ultrasonic and pressure sensors can be thrown off by temperature and condensation. The client wanted a compact, accurate, non-contact level monitor built on the VL53L0X time-of-flight (ToF) sensor, with no moving parts, that reports levels remotely and runs on a battery.
Mechanical wear
Float switches and other moving parts wear out and fail over time.
Environmental effects
Temperature, condensation, steam and dust can distort level readings from conventional sensors.
Manual inspection
Without remote readings, staff must check tanks by hand and may notice low levels too late.
Long battery life
Many tanks have no convenient power, so the monitor had to run on a battery for a long time.
Impact figures describe the situation before the project, as the client reported it to us; we did not measure them.
Our solution
The monitor mounts above the liquid and uses the VL53L0X, which times how long a pulse of infrared laser light takes to bounce back, to measure the distance to the surface. Cover-window crosstalk calibration (ST's documented procedure) and outlier filtering reduce the effect of condensation and dust on the sensor window; dense steam or dust inside the tank scatters the laser and cannot be calibrated out. A low-power embedded system sends readings over LoRa, BLE or Wi-Fi to a cloud dashboard, which shows live levels, raises alerts, pushes mobile notifications and can trigger a refill pump when the level drops below a threshold.
System architecture
Sense, compensate, transmit, act.
Sensing
- VL53L0X time-of-flight distance sensor
- Non-contact: no floats or moving parts
- Cover-window crosstalk calibration and outlier filtering
Embedded and radio
- Low-power embedded system with RTOS firmware
- LoRa, BLE or Wi-Fi telemetry
- Battery-powered operation
Cloud and automation
- Cloud dashboard with live tank levels
- Threshold alerts and mobile notifications
- Refill-pump trigger on low level
Key design points
- Sensor
- ST VL53L0X time-of-flight
- Sensor range
- Up to 2 m indoors, white target, no IR (VL53L0X datasheet); ~0.8 m in 5 klx daylight
- Measurement
- Non-contact distance to surface
- Telemetry
- LoRa (IN865 band, 865–867 MHz), BLE or Wi-Fi
- Power
- Battery; >1 year (design target; depends on reading interval and radio)
- Automation
- Low-level refill-pump trigger
What we delivered
- VL53L0X integration for non-contact level measurement
- Cover-window crosstalk calibration and outlier filtering
- Low-power RTOS firmware
- LoRa, BLE and Wi-Fi telemetry options
- Cloud dashboard with live levels and alerts
- Mobile notifications for refill and depletion
- Refill-pump automation on a low-level threshold
Outcome
The monitor replaced float and pressure sensors with a non-contact ToF measurement, so there are no moving parts to wear out, and remote readings reduce the need for manual tank checks. The system suits covered industrial, agricultural and residential tanks within the sensor's range. The VL53L0X's 2 m figure applies indoors to a white target with no ambient infrared; sunlight on the target and weakly reflecting clear-water surfaces shorten it, so for tanks deeper than about 1.5 m, or where sunlight reaches the liquid, a longer-range ToF sensor (such as the VL53L1X) or an ultrasonic or radar sensor is the better choice. Battery life of over one year is a design target. We do not publish an accuracy figure: the VL53L0X datasheet specifies accuracy as a percentage of distance, and no test protocol for the installed system is on record.
How to read the labels: Design target = an engineering target, not a field measurement; Client-reported baseline = the client's own figure for the situation before the project; we did not measure it. Figures without a label are specifications or project scope.
Battery-powered operation
Design target>1 year
Design target; depends on the reading interval and which radio is fitted
Moving parts
None
Replaces float-based and pressure sensors
Automation
Refill trigger
Starts a refill pump when the level drops below a threshold
Design duration
6 months
Hardware, firmware, telemetry and cloud dashboard
Technologies used
- VL53L0X
- Time-of-flight (ToF)
- LoRa
- BLE
- Wi-Fi
- RTOS
- Cloud dashboard
- Mobile notifications
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