About VL53L5 sensor

[ahsrabrifat]

Hello, I have just read this article https://www.theengineeringprojects....e-distance-sensor-for-presence-detection.html regarding the VL53L5 Time-of-Flight (ToF) 8x8 multizone ranging sensor with wide field of view sensor. Here is the datasheet. https://www.st.com/en/imaging-and-photonics-solutions/vl53l5cx.html
It is not that much available where I live. If I want to use one, I may need to source one from alliexpress or some other source.

What I need to know is, does it worth the price? Does anyone have practical experience in using this sensor? Is it better than the HCSR04? I wish to work on an occupancy alert device. Will it be a better choice than the generic PIR and SONAR sensors? If yes, what are some dependable sources from where I can buy this? Thank you.

 

[D.A.(Tony)Stewart]

For outdoors with moving trees, leaves, PIR is the sensor of choice for warm intruders but are slow but perhaps reliable.

Pulse reflected IR with AGC Rx like those used for driveway lights which can detect far and wide easier for the slightest change in Rx levels.

Multiple pulse reflected paths being interrupted is another option but more critical in setup using narrowband emitter/detectors.

The Laser ToF looks powerful but depends on range you need. Is this for more than 10 or 20 m or off walls in closer?

Ultrasound device sounds flaky with false alarms at far distances.

I think the old fashioned IR method is adequate for indoors, although I had once made one with VHF RF reflections back in the 70's up to 10 wavelengths using a directional coupler or splitter to a diode and uV signal change.

 

[FvM]

Not sure what's your application, for applications mentioned in the product presentation, laser TOF sensors are unrivaled, I think. Useful range of VL53L5 is restricted to about 1 m under bright ambient light conditions.

 

[D.A.(Tony)Stewart]

With an accurate measurement up to 4m TOF is OK. But if you want a reliable low cost motion security sensor, I would not recommend it for its cost and complexity.

However you need to define objects and range for test purposes. One purpose is to define the minimum object size, distance and speed range to define for a) false positive errors and true negative errors (missed alarm). Without these reasonable specs no system can be perfect. i.e. Do you want to detect a child but ignore a pet?

I believe the best solution already exists with motion controlled exterior lights (however they work(?)

My thoughts are as follows for a design spec depend on if you are designing an Occupancy Sensor or an Intrusion Sensor.

Active IR Diffuse Reflection Motion Sensors using a high current 10%d.f. pulsed emitter in the range of 10kHz to 50 kHz not commonly used by remote controllers.
Then use an IR Rx similar to the 38 kHz digital remotes with a BPF Q=10 + AGC except with a stable log amplifier detect any small change in the diffuse Rx signal with a high CNR carrier ratio and high SNR of demodulated motion signal such that it can detect a person moving slowly at xx m distance.

The carrier f, and Q of BPF improves the range or sensitivity or SNR but also improves immunity from interference.

I would try the top two frequencies and detect then detect changes in amplitude with a suitable detector for motion.

https://www.vishay.com/docs/82489/tsop322.pdf

These were formerly designed and built by Sharp , the leader in this optical design.

For this to work the Emitter and Rx must be optically isolated. Then design like above digital ones except analog out and detect change in reflection.
You will need a shield and very clean DC power.

 

[ahsrabrifat]

Not sure what's your application, for applications mentioned in the product presentation, laser TOF sensors are unrivaled, I think. Useful range of VL53L5 is restricted to about 1 m under bright ambient light conditions.

I want to make an occupancy alert for school toilets. If someone is in the toilet, a red bulb will be glowing outside the toilet. Then the toilet is empty, the bulb will be off.

--- Updated Mar 21, 2025 ---

With an accurate measurement up to 4m TOF is OK. But if you want a reliable low cost motion security sensor, I would not recommend it for its cost and complexity.

However you need to define objects and range for test purposes. One purpose is to define the minimum object size, distance and speed range to define for a) false positive errors and true negative errors (missed alarm). Without these reasonable specs no system can be perfect. i.e. Do you want to detect a child but ignore a pet?

I believe the best solution already exists with motion controlled exterior lights (however they work(?)

My thoughts are as follows for a design spec depend on if you are designing an Occupancy Sensor or an Intrusion Sensor.

Active IR Diffuse Reflection Motion Sensors using a high current 10%d.f. pulsed emitter in the range of 10kHz to 50 kHz not commonly used by remote controllers.
Then use an IR Rx similar to the 38 kHz digital remotes with a BPF Q=10 + AGC except with a stable log amplifier detect any small change in the diffuse Rx signal with a high CNR carrier ratio and high SNR of demodulated motion signal such that it can detect a person moving slowly at xx m distance.

The carrier f, and Q of BPF improves the range or sensitivity or SNR but also improves immunity from interference.

I would try the top two frequencies and detect then detect changes in amplitude with a suitable detector for motion.

https://www.vishay.com/docs/82489/tsop322.pdf

These were formerly designed and built by Sharp , the leader in this optical design.

For this to work the Emitter and Rx must be optically isolated. Then design like above digital ones except analog out and detect change in reflection.
You will need a shield and very clean DC power.

I want to make an occupancy alert for school toilets. If someone is in the toilet, a red bulb will be glowing outside the toilet. Then the toilet is empty, the bulb will be off.Do you think this sensor will be a good choice for accurate human detection inside a toilet?

 

[D.A.(Tony)Stewart]

I want to make an occupancy alert for school toilets. If someone is in the toilet, a red bulb will be glowing outside the toilet. Then the toilet is empty, the bulb will be off.

--- Updated Mar 21, 2025 ---

I want to make an occupancy alert for school toilets. If someone is in the toilet, a red bulb will be glowing outside the toilet. Then the toilet is empty, the bulb will be off.Do you think this sensor will be a good choice for accurate human detection inside a toilet?

Is it impossible to buy a similar function? What is your budget? qty? What power? DC? 5V? Wireless?

 

[ahsrabrifat]

Is it impossible to buy a similar function? What is your budget? qty? What power? DC? 5V? Wireless?

Sir, I am planning to make a prototype and demonstrate it to different school authorities. If they approve my idea, then I will be able to determine how many I need to manufacture. I'd like to power it from a 220V power outlet because I think that will be the most convenient way to power it. I aim to sell each unit for BDT 10K at best. (Approximately 100 dollars)

 

[D.A.(Tony)Stewart]

You better work out the practical wiring and appearance aspects of the design. I believe active diffused IR carrier detection is likely the best solution for immediate response but lack of motion after the timeout delay can create a false vacancy, so sensitivity must be maximized. However you will need to bring down your price to guarantee success.

It must also be protected against vandalism and unsafe 220V in washrooms.

 

[ahsrabrifat]

You better work out the practical wiring and appearance aspects of the design. I believe active diffused IR carrier detection is likely the best solution for immediate response but lack of motion after the timeout delay can create a false vacancy, so sensitivity must be maximized. However you will need to bring down your price to guarantee success.

It must also be protected against vandalism and unsafe 220V in washrooms.

Thank you, sir. I wish to post updates on my work here.

 

[D.A.(Tony)Stewart]

A good choice to detect reflections off person and walls up or down...

https://www.vishay.com/docs/82483/tssp60.pdf

 

[ahsrabrifat]

A good choice to detect reflections off person and walls up or down...

https://www.vishay.com/docs/82483/tssp60.pdf

I never came across this particular component. Thank you once again, sir.