LIDAR-Lite Laser Rangefinder - Simple Arduino Sketch of a 180 Degree "Radar" | RobotShop Community

I would be very thankful if you can answer my question, Can I use this Lidar for measure height? for example, can I use it to measure the height of the tree? Thank you

Would the measurement of water in a vertical pipe be refelected with no pipe wall interference inside the pipe ?

@swefe: Short answer: maybe.
Long answer: It depends on multiple factors. First, the signal may or may not reflect on the water depending on angle and composition. You will need to test this. As for the pipe size, it depends on the distance. For short distance / larger pipes, that may be OK. The divergence is 8 mrad, so @ 100 cm distance the spot would be roughly 0.8 cm of radius (or ~1.6 cm wide/diameter). The size of the spot is linearly proportional to the distance.

@Elnaz: Maybe. In a general sense, the LIDAR-Lite is a distance measurement sensor. Therefore, you can use it to measure the distance between two points: the sensor itself and the target.
A simple (but impractical) way to get the height of a tree would be to take a measurement from the top of the tree towards the ground. Of course, that is most likely not feasible in most cases.
Instead, you can use trigonometry to help you. Choose a far enough away point from the tree’s base and measure the distance from the ground to the tip of the tree. Take note of the angle of measurement relative to the ground, too. Then, from the same point, measure the distance to the tree trunk horizontally. Some basic trigonometry should help you figure out the height (missing length). Here’s a link to a useful online trigonometry utility calculator.

I would like to know can I measure the hight of the tree with this LIDAR? which angle can I take with this device?

@Elnaz: As mentioned in our previous response, other than measuring from the tree top, you can use some trigonometry to measure it from the ground, too.
Here is a good article about it: https://www.monumentaltrees.com/en/content/measuringheight/

I’m looking for a device that will allow me to establish the position of moving objects (2 dancers) on a 30X30 stage. Would this be an appropriate solution?

@jfhallst: This example project would most likely not be suitable for moving objects (such as dancers). This is meant for robot collision detection at low speed, such as detecting walls and other large obstacles while not moving or moving very slowly. This is mostly due to the setup being quite slow and having only one beam.
You would probably be better off using one of our other LIDAR product, such as our rotating or multi-beam ones.
Alternatively, you could try using a stereo-camera system to detect the dances, such as this one.

Is it possible to use the Arduino IDE to write sketches that capture data from the rotating LIDAR? (As I understand it, the example code for the inexpensive one you sell is all in C and I haven’t been able to find any example sketches that show how to do it using the Arduino language.) I’m a fairly novice programmer.

@jfhallst: Actually, the example for this blog article is Arduino code. It was done using a Lynxmotion BotBoarduino, which is an Arduino-compatible board with better support for projects using servomotors and dual power supplies (one for electronics, one for motors).

It should be noted that Arduino sketches are basically C/C++ with added pre-processing (extra features for Arduino).

Could you link to specific products? That would help us provide more details, maybe even actual example code.

Please note that what you are trying to create (track two moving objects in a large space) is typically not a trivial project and therefore maybe not the best project to start with. That being said, you can certainly learn much from it but it will require a lot of effort (and most likely many hours of frustration with things that don’t work quite as you want them too :stuck_out_tongue: )

I’m wondering if this device can be used to measure the speed/distance of an athlete travelling down a runway (long jump or pole vault) in order to create a plot of speed at each measured distance along the run (for each the runs are less than 40 meters). The most important thing is the speed at takeoff, but having an acceleration curve would provide interesting data concerning the quality of the run.

@DLee
The sensor is designed to measure distances to an object, typically the floor (UAV) or walls/large obstacles (robots in general). That being said, you can of course use it for other purposes.

You results may vary depending on how well the signal bounces back to the sensor from the athlete. The best here would be to try it out and see how it goes. Maybe try and aim at the back of the athletes where you could have a large reflective surface to target?

Good luck!

Thanks…looks like this is in the infrared spectrum. Can the point be imaged at 30-40 meters on a target with an infrared camera or other device for aiming purposes?

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Indeed, it is using a 905 nm wavelength as seen in the product’s specifications.

Well, at 30-40 meters you won’t have a point at all. Also in the specifications it is specified that the beam divergence is 8 mili-radian (or ~0.458366°). This translates to a spot size of at least 24 cm @ 30 m and at least 32 cm @ 40 m.

The signal itself it not simply a on/off but hundreds of IR pulses with different signatures that are correlated by the device to get a proper measurement, so it might not be as easy to see as expected.

That being said it may still be possible to see it using a camera or other image capturing device that is sensitive to IR. I’ll see with the manufacturer what they think about this and post here again once I have more information.

I hope the info above helps you understand a bit better the sensor and how it functions.

Sincerely,

Hi,

I’m quit new with the lidar lite v3, overall it works, my problem is accuracy of short distances (between 0 and 50 cm). Between 50-30 cm, the measurment of the lidar is 10-15 to high (50 is 63, 40 ist 51 etc.) Strange thing, smaller than 30 cm the measured figures arises to 45 47 ? I use an arduino uno v3 and the sample files from github (https://github.com/garmin/LIDARLite_Arduino_Library). I played with the option, but there are no changes? Many thx in advance for any hints. (as I said in quite new with Lidar sensors)

Peter

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Hi @pd,

Welcome to the RobotShop community! :slight_smile:

With the LLV3 [RB-Pli-06] you’ll find that measurements under 30-60 cm (varies per product) will most likely never be very reliable. This is in part due to the fact that the lenses and setup of the hardware is meant for distances of up to many meters (~40 m in this case). When the sensor is very close to a target, you get two issues:

  1. The angle of the transmitter vs receiver with the lens is wrong and introduces errors (i.e.: too close)
  2. The receiver gets saturated with the return signal (i.e.: too strong), especially with a very reflective target

You may be able to tweak some registers to help a bit (see datasheet, page 4), but expect operation < 60 cm to not be great and operation < 30 cm to not be usable.

All sensors have maximum ranges but they typically also have minimum ranges and people don’t tend to talk about those as much, at least when starting out. And, in most cases, it is not an issue.

If you need to measure distances to obstacles/objects at a much short range I’d recommend looking at sensors with smaller usable minimum range, such as RB-Pol-633, which can work for 4-400 cm. There’s also other versions with close to 0 cm minimum range.

In systems where measuring a very long and a very short range is expected to happen / is required, then you’d simply use two systems, such as a RB-Pli-06 and a RB-Pol-633. When the distances get shorter in the working range of the RB-Pli-06 (i.e.: < 3.5 m) your code switches to using the RB-Pol-633. When the distances get > 3.0 m, lets say, then you start using the RB-Pol-06 as the dominant value.

Sincerely,

Hi ‘scharette’ (hope you like this title?),

first of all many thx for your quick and verbose answer! I think, the advice of am friend of my was not so good. I use a diddy borg from Piborg inside and I fisrt of all I used the Ultrasonic distance sensors, but they are unfortunatelly to ‘unreliable’ for my feeeling. Your hint to use a ToF sensor is a good idea, so I will follow this in the next time. I think to use two one in front of my diddy borg could solve my problems. It will be a little bit simpler, because I’m a quiet good python programmer and experienced raspi guy, but only a novice in C and arduino :slightly_smiling_face.
Again many thx, I hope you are well during this times … have a nice evening wherever you are …

kind regards

Peter

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@pd / Peter

All good! :slight_smile:

Most low cost ultrasonic sensors are only really good for determining if you have a wall or other large obstacle or not. The further the obstacles are, the longer the reply takes, too (well, same for LIDAR, but light is so much faster than sound!). Also, ultrasonic sensor placement is more problematic due to large cone size of the signal. You can easily get false positives from the robot or the floor/ceiling, depending on how you use it.

Since you already have a LIDAR-Lite, one trick you can use is to place it at the back of the platform facing forward. This will prevent most of the “minimum range” to be accessible and provide more reliable readings.

I’ve even had a student previously add a “stick” to the robot extending behind it so the sensor they were using cleared the minimum distance completely (the robot was 10 cm long, the arm another ~10 cm for a sensor with minimum range of ~15 cm). That way, you can dodge the issue completely. Just make sure nothing gets in front of your sensor! :slight_smile:

Good luck with your project!

Same to you! I’m in EDT, so it is mid-afternoon at the time of writing this. :wink:

Hi,

there is no way to change the Pimoroni ToFs I2C address permanently. Do you know VL531LX or similiar ToFs, which are able to use in parallel with permanent different I2C addresses. Important for me is, because the rest of my robot stuff uses Raspi and Python, that there is a Python lib for raspi available for easy getting the the two distance value in my current code (like Pimoroni it offers, https://github.com/pimoroni/vl53l1x-python) I cannot change to arduino, because my current motor controller cannot be handled by arduino. I would like to use 2 ToVs like headlights in a car :slightly_smiling_face:
This would be very helpful for me, because my robot works indoor …
My thx in advance …

regardly

Peter

I saw that the new iPhone has this technology, and it helps them make better portrait photos.