NatePiVision
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Looking for a radar/radio based rangefinder

Thu Dec 01, 2016 1:52 pm

Hi Everyone,

I'm searching for a radar based rangefinder that would work up to 50m, and surprisingly, I cannot find anything at all. Usually the search for 'radar rangefinder' ends up with ultrasonic or other technologies, but I want actual radar/radio. I'm surprised that I can't find anything because radars that work with this distance are mass produced for lots of applications, especially automotive. The closest thing I've found for my application is the Lidarlite sensor which works up to 40m, but it's turned out to be too finicky for the application due to sensitivity to ambient light, varying surface shapes, and varying surface reflectivity.

Anybody used anything in the past? Or has anybody seen how to utilize an automotive sensor?

Thanks,
-Nate
Current Pi based projects:
https://github.com/nategreco/DAPrototype - Advanced Driver Assist System (ADAS)
https://github.com/nategreco/StereoVisionTest - Stereo vision (CM3) test setup

Videos:
https://youtu.be/WRAR0lgYsj8
https://youtu.be/SyvCJLRw1UQ

Moe
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Re: Looking for a radar/radio based rangefinder

Fri Dec 02, 2016 10:20 pm

I have used actual radars in the past, but only at work. They tend to be expensive. If you can get hold an automotive one, I'm sure it could be hacked but I'm not aware of anything sold for the hobby market.

I've always had a vague idea that it should be possible to use the magnetron from a microwave oven as the transmitter, but I've never heard of anyone actually doing it.

Sorry, that wasn't much help was it? :)
Submarine communication systems engineer and amateur robot enthusiast.

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jbeale
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Re: Looking for a radar/radio based rangefinder

Fri Dec 02, 2016 10:40 pm

I don't have an answer for you, but I'll point out that "varying surface shapes and varying reflectivity" applies to radar systems as well.

There is this: http://hackaday.com/2012/12/18/build-a- ... ourseware/

As you probably know, you can get a short-range motion-sensor (not rangefinder) doppler radar for about $5 like
http://www.ebay.com/itm/HB100-Microwave ... 1567660932

I wonder if it could be adapted with some circuit modifications into a rangefinder. Probably very short range, if so.

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Burngate
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Re: Looking for a radar/radio based rangefinder

Sat Dec 03, 2016 11:23 am

That E-bay device uses 40mA at 5v - 200mW. The MIT course specifies 10mW of TX power.
A microwave oven -at least mine - provides 800W of microwave power.
I'd rather not be standing in front of a radar device powered by a microwave oven!

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scruss
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Re: Looking for a radar/radio based rangefinder

Sat Dec 03, 2016 2:10 pm

This is likely an "Accurate, Range, Cheap: pick one" situation. A friend made a lovely giant touchscreen based on a scanning lidar placed in the bottom corner of the flat screen array. The sensor was a pricey rental (likely around $10k to buy, if these products are anything to go by), was slightly affected by sunlight, but still worked and had to mask out returns from buildings 80m+ away.
‘Remember the Golden Rule of Selling: “Do not resort to violence.”’ — McGlashan.

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Ronaldlees
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Re: Looking for a radar/radio based rangefinder

Sat Dec 03, 2016 2:56 pm

The magnitron is used in the old style 4KW pulse radars (since from about WWII).

However; the new radar uses solid state broadband techniques (like the Lowrance 3G and 4G radars). The broad band radars have good definition and range accuracy. I think I read that they're quite a bit better at close ranges than the old time pulse units, but don't quote me. The 3G comes in at around $1200, so - like the other poster said, they're still a little expensive. The prices on these units will start to come down though, over time, because they're not that expensive to build, and pleasure yacht owners are starting to buy them in place of the old pulse (power hungry) stuff. I think I saw one once for around 800 bucks. Don't remember which brand. It's possible one could pick up a used unit cheaper.

Those radars are good for many miles :-)

Some countries may not allow them on terra firma though. You'd have to check. I doubt you're interested in a commercial unit, given the pricing. I don't know if the kit is available for DIY projects. Patents? The 77 GHz automotive radar may be better, cost-wise, but I haven't seen any sources. Patents? LOL

The HB100 that is mentioned by poster jbeale goes only to 20 meters according to the listing, so short of your 50m requirement. I do know of people using the HB100 for 10 GHz communiations though (with a license).
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NatePiVision
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Re: Looking for a radar/radio based rangefinder

Sat Dec 03, 2016 5:13 pm

Hmm, thanks for trying guys, but you're turning up the same kinda stuff that I am. What I want (demanding aren't I?) is a prepackaged unit with I2C or some other serial communication just like the LidarLite, but with radio technology. A lot to ask? I don't think so.
This is likely an "Accurate, Range, Cheap: pick one" situation.
I disagree. Why?
Because radar sensors that easily fit this application are out there mass produced in commercial products. Check this guy out:

https://buy.garmin.com/en-US/US/into-sp ... html#/home

$200 USD, 140m, and works with cars out doors (varying environmental conditions, surface shapes, etc). Plus, I assume a good chunk of that $200 isn't in the radar sensor itself and is in the packaging, marketing, indication, and electronics interpreting the signal. I'm only asking for 30% of that distance, and of course cost relative to sensing distance is exponential, so it's likely possible to make a sensor much cheaper. And even the HB100 unit, which is just a dumb sensor, works 20m with similar technology and only costs $5. I don't think its a matter of the cost of the technology, and for my application accuracy isn't super critical. Even cost I'm willing to spend +$200. It's just a 'doesn't exist' issue.

I guess the issue is there just isn't demand enough for somebody to make a DIY radar sensor, which is probably true, but I don't see the demand for a LIDAR unit either and there's a whole tone of DIY LIDAR sensors.

I guess hacking an automotive unit is likely my best option, it's just not an easy job and I don't have a car with adaptive cruise control to reverse engineer the technology. I've read this thread:

http://diydrones.com/forum/topics/repur ... or-uav-ugv

And essentially I'd have to invest a lot of time into listening in on the communication between a car and the ACC unit to understand what commands to send. Something I'm willing to do if I had a car to mess with. Maybe one of my next rental cars will have ACC.
Current Pi based projects:
https://github.com/nategreco/DAPrototype - Advanced Driver Assist System (ADAS)
https://github.com/nategreco/StereoVisionTest - Stereo vision (CM3) test setup

Videos:
https://youtu.be/WRAR0lgYsj8
https://youtu.be/SyvCJLRw1UQ

NatePiVision
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Re: Looking for a radar/radio based rangefinder

Sat Dec 03, 2016 5:24 pm

Also, the Lowerance 3G, is an interesting suggestion. Way too much for my application, but I wonder if there's better options in the marine/aviation world. I've been looking specifically at hobbyist drones, but LIDAR seems to be popular there.

http://www.westmarine.com/buy/lowrance- ... --12677993
Current Pi based projects:
https://github.com/nategreco/DAPrototype - Advanced Driver Assist System (ADAS)
https://github.com/nategreco/StereoVisionTest - Stereo vision (CM3) test setup

Videos:
https://youtu.be/WRAR0lgYsj8
https://youtu.be/SyvCJLRw1UQ

NatePiVision
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Re: Looking for a radar/radio based rangefinder

Sat Dec 03, 2016 5:27 pm

Burngate wrote:That E-bay device uses 40mA at 5v - 200mW. The MIT course specifies 10mW of TX power.
A microwave oven -at least mine - provides 800W of microwave power.
I'd rather not be standing in front of a radar device powered by a microwave oven!
Ha, I'm sure you can tune it down :D . However, that MIT article is very interesting. Cool stuff.

I think there's options for 'homemade' solutions out there, but in the end I think I'd just be better off hacking an ACC unit from a car or getting my Lidar sensor to work better.
Current Pi based projects:
https://github.com/nategreco/DAPrototype - Advanced Driver Assist System (ADAS)
https://github.com/nategreco/StereoVisionTest - Stereo vision (CM3) test setup

Videos:
https://youtu.be/WRAR0lgYsj8
https://youtu.be/SyvCJLRw1UQ

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scruss
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Re: Looking for a radar/radio based rangefinder

Mon Dec 05, 2016 12:53 am

NatePiVision wrote:$200 USD, 140m, and works with cars out doors (varying environmental conditions, surface shapes, etc).
A car produces a huge radar return, so not my definition of accurate
‘Remember the Golden Rule of Selling: “Do not resort to violence.”’ — McGlashan.

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Gavinmc42
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Re: Looking for a radar/radio based rangefinder

Mon Dec 05, 2016 2:53 am

http://diydrones.com/forum/topics/we-co ... -for-uav-s
http://www.smartmicro.de/

See what Tesla is using
Lots of cars with auto radar now, bit expensive on high end models but as it get cheaper we will probably see it on all cars.

Probably end up as low as $10-20 for the TX/RX which could be single chip device on PCB.
Wow, nearly there?
http://mwrf.com/blog/5-new-things-do-single-chip-radar
http://www.eetimes.com/document.asp?doc_id=1328575
http://www2.imec.be/content/user/File/L ... eaflet.pdf
https://www.viasat.com/technologies/sin ... ransceiver
http://www.infineon.com/cms/en/about-in ... 0-001.html

Would be great for flocking drones and robots
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jbeale
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Re: Looking for a radar/radio based rangefinder

Mon Dec 05, 2016 4:44 pm

"World's first cycling radar that warns of vehicles approaching from behind up to 153 yards (140 meters)"

Thanks for posting that link, it sounds like a cool widget. In pedantic mode now, I note that "up to 140 meters" means... what? The brightest retroreflective radar object they could find showed a hit once at 140 meters? I think what you are asking for is a guaranteed or even just typical or expected minimum detection range, and I do not see that specified.

EDIT: from this review https://www.dcrainmaker.com/2015/10/gar ... eview.html the bike unit apparently does what it is intended to do. It will apparently pickup cars, usually mopeds, and sometimes also larger bicycles. They don't say at what range, though.

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Pekka
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Re: Looking for a radar/radio based rangefinder

Tue Dec 06, 2016 8:31 am

NatePiVision wrote: I'm searching for a radar based rangefinder that would work up to 50m...
Anybody used anything in the past? Or has anybody seen how to utilize an automotive sensor?
Here is a scientific article on the topic: http://www.mdpi.com/2079-9292/5/2/19/htm
We used this radar sensor with the manufacturer-provided DSP board: https://www.rfbeam.ch/product?id=17

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Ronaldlees
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Re: Looking for a radar/radio based rangefinder

Tue Dec 06, 2016 6:02 pm

Pekka wrote:
NatePiVision wrote: I'm searching for a radar based rangefinder that would work up to 50m...
Anybody used anything in the past? Or has anybody seen how to utilize an automotive sensor?
Here is a scientific article on the topic: http://www.mdpi.com/2079-9292/5/2/19/htm
We used this radar sensor with the manufacturer-provided DSP board: https://www.rfbeam.ch/product?id=17
Thanks for a very interesting link. It does seem like the distributors are of the "give us a call and we'll talk" variety. That means most of us Pi forum guy's companies/pocketbooks aren't big enough :-(
I am the Umbrella man

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Pekka
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Re: Looking for a radar/radio based rangefinder

Wed Dec 07, 2016 5:36 am

Thanks for a very interesting link. It does seem like the distributors are of the "give us a call and we'll talk" variety. That means most of us Pi forum guy's companies/pocketbooks aren't big enough :-(
Well, they were quite supportive when we were inquiring about their products, eventhough we clearly stated we only need a single piece. They were even kind enough to somewhat tweak the DSP board firmware to our suggestions and help us locate the noise source. We did communicate per e-mail rather than phone, though.

NatePiVision
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Re: Looking for a radar/radio based rangefinder

Wed Dec 07, 2016 12:15 pm

Wow, now that's way more information than I turned up. Thanks guys.

Scruss, you're right, I should have specified the size of the object. I am trying to use radar to detect automobiles. I guess that's why I thought it should be easy for me to find something. Anything used for Forward Collision Warning / Adaptive Cruise Control would work perfectly.

Also, the link posted by Gavinmc42 on the DIY drones thread pretty well sums up the issue at the end:
We're not pursuing that idea anymore. But the technology is available, just not as an out-of-the-box solution. Check out xethru.com if you want to pursue the idea yourself.
Too bad those guys backed out of that, sounds like they were going to make exactly what I'm looking for.

Seems to me there's the following options, but they all require me to contact them directly or a distributor, never a good sign for the home hobbyist :( :
http://www2.imec.be/be_en/research/wire ... radar.html
https://www.xethru.com/x2-uwb-radar-chip.html/
http://www.nxp.com/products/rf/millimet ... metric_Tab
http://www.autonomoustuff.com/product/s ... ive-radar/
Current Pi based projects:
https://github.com/nategreco/DAPrototype - Advanced Driver Assist System (ADAS)
https://github.com/nategreco/StereoVisionTest - Stereo vision (CM3) test setup

Videos:
https://youtu.be/WRAR0lgYsj8
https://youtu.be/SyvCJLRw1UQ

NatePiVision
Posts: 72
Joined: Fri Apr 29, 2016 5:38 am
Location: Pittsburgh
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Re: Looking for a radar/radio based rangefinder

Wed Dec 07, 2016 12:21 pm

On another note, I thought it funny that I did just get a rental car with adaptive cruise control (2017 Toyota Corolla) and have it for 3 weeks. I suppose I could hookup a sniffer and listen in on the messages between the ACC module and the ECU to figure out how to use one for my own project, but I'm realizing now a used ACC module is still going to run me ~$500, which is out of my price range, at least for now.
Current Pi based projects:
https://github.com/nategreco/DAPrototype - Advanced Driver Assist System (ADAS)
https://github.com/nategreco/StereoVisionTest - Stereo vision (CM3) test setup

Videos:
https://youtu.be/WRAR0lgYsj8
https://youtu.be/SyvCJLRw1UQ

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