Go Down

Topic: Narrow field of view distance sensor for 1mm accuracy @1m distance (Read 276 times) previous topic - next topic

Nazaar--

Hi all,

I'm looking for a reasonably accurate (within 1mm), portable, distance sensor with a very narrow field of view, or something that the FOV can be narrowed. The distance measured is less than 1m.

I know part of this question gets asked regularly, and have searched, but the 1) new sensors come out regularly, and I continue to search every few months, but there's a lot of people here, so I'm hoping that someone knows more than I do about what's current, and 2)multiple measurements with a narrow field of view isn't something I've found an answer to.

Some of the researchers I work with look at soil accumulation or loss. The current way of doing this is to have an array of vertical rods that hang from a horizontal crosspiece. The rods are lowered until they touch the surface of the soil, and how much is left above the crosspiece is measured with a ruler. Measurements are made regularly to see if the level of sediment at that point has gone up and down (see quick drawing attached).

So the question is whether it's possible to replace this with an arduino with a sensor, or sensors, attached. The ultimate aim is to have something that can be left in place to continue to log measurements over time, in remote field locations, but in the interim something that can just measure the distance directly below a known point, and display the result would be better than what they're using.

I've tried the PING laser sensors, and the maxbotix sensors, and the issue is their FOVs are just too wide. They're designed for measuring distance to something flat.

Anyone have any opinions on whether this possible within a reasonable budget, say 50-80USD/sensor?

Thanks

humandroid


Nazaar--

Hi,

can you define more precisely "Narrow"?
Good point! Sorry, should have included it. 10mm spot at 1m distance, so in degrees I guess it's about 0.6 degrees FOV.

humandroid

mmh, I'm not sure a product fitting your requirements exists

MarkT

You need true Lidar, and something like this is about the cheapest I think: https://www.generationrobots.com/media/rplidar-a1m8-360-degree-laser-scanner-development-kit-datasheet-1.pdf

Unless you can find a non-scanning version which might bring the cost down.

Fake Lidar (IR time-of-flight) doesn't seem to do better than 1cm.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

Nazaar--

mmh, I'm not sure a product fitting your requirements exists
It sounds like it doesn't, at least within the price range, which is disappointing, but not much to do I guess.


You need true Lidar, and something like this is about the cheapest I think: https://www.generationrobots.com/media/rplidar-a1m8-360-degree-laser-scanner-development-kit-datasheet-1.pdf

Unless you can find a non-scanning version which might bring the cost down.

Fake Lidar (IR time-of-flight) doesn't seem to do better than 1cm.
I've had a look at the lidar-lite products, I assume they're one of the 'fake lidar' products you're talking about, expensive and +/- 2.5cm isn't good enough.

Thanks for the suggestion of true lidar, and that model. The scanning aspect might actually solve the need for multiple sensors if it produces a 2D image of good enough resolution. Figure 2 seems to say it'll get 0.5mm resolution at less than 1.5m, which would be ideal, if very expensive.

Thanks for the help.

Go Up