Needa Radar sensor, NOT CW, but good for stationary object ranges?


#1

BLUF: Looking for advice on a radar sensor for range.

Not a Lidar, and not a radar that only looks at Doppler to discern movement… so not a continuous wave (CW) radar. Can be a microwave sensor too. Just needs to detect a stationary car at a meter or two. This would lend itself to a Time of Flight setup… literally just like the VL53L1X Lidar from STmicroelectronics - but not that frequency.

Anybody have any knowledge of such a device? Even an existing sensor with one already integrated?


#2

There are other lidar’s similar to the VL53L1X that operate at different optical wavelengths. Here is one that works at 850nm (instead of 940nm):


#3

Thanks for replying BKO.
I have tried that Lidar and a few others (Sharp, Garmin). They all suffer the same lack of robustness and reliability in sunlight and adverse mediums. This is why I am abandoning Lidar. I want to find a radar ( or microwave) device. They do better in sunlight and adverse mediums, they just tend to be for movement detection and not range… though range detectors exist. So I have to double-down on sticking to Radar/microwave.


#4

Have you chosen a microwave module / system for the application? I have worked with some similar projects… Perhaps a FM-CW radar for ranging? I agree - IR is often subject to interference… same for microwave, just different interference.


#5

Yeah I think there was a misunderstanding of terms on my end… so the FM (frequency modulated) part of the FM-CW (or CWFM) radar should allow for round trip time (RTT) measurement… meaning I can get distances to stationary objects! Thanks for the tip!

Is there one you could recommend offhand? small, low power, robust, detections from 0.1 to ~3 meters?

In fact, I wonder if I can just find a Frequency Modulated Radar - that is not CW, but can be turned off and on… to minimize energy consumption. Perhaps that is the way the sensors are made in the first place and I’m just ignorant on the topic.


#6

Jack,

I develop on multiple embedded platforms and have had the need for microwave ranging in the past… It’s difficult but not impossible, recommend an existing FMCW project such as Walabot (google search that), or your own solution based upon similar hardware (Amazon).

Not sure how the K-band ~24GHz FCC spectrum auctions will impact K-band operations but depends on jurisdiction where you live (FCC USA).

I do not endorse or promote the product mentioned above just have experience with same. Glad to see folks working in the FMCW RADAR area, this may become common with ASIC RADAR processors becoming commonplace.

Best of luck & would love to hear of your solution! Best, _Todd


#7

Thanks Todd. I just had a presentation from the omnipresence folks today… I talked with them afterward… very excited about what they are making over the next several months.


#8

Good find! That’s very similar to what we use in some legacy applications. Getting the RADAR data processed by a dedicated Radar Signal Processor (or RSP) makes programming the application code easier IMHO. In some cases I just need a “presence” pull-up, in other cases I need to know “distance to object”, and once you have those two - why not add Doppler as in your example!

Good discussion - Best Regards, _Todd


#9

I have not personally tried any of these but below are some 24GHz microwave radar sensors:

https://www.ebay.com/itm/254161579667

https://www.ebay.com/itm/254161585634

https://www.ebay.com/itm/254197360658

https://www.ebay.com/itm/254161592343

The last seems to even detect moving vehicular targets at high speeds.


#10

Thanks for posting! I think this thread will be useful for other folks looking for a ranging radar!