Hi. I’m searching for a device capable to take measurements at 20Hz rate at very least at 10 meters distance (longer distance and higher rate is better 
) but this is a bare minimum I need, for obstacle avoidance purposes.
I saw this radar https://www.sparkfun.com/products/24540, but I can’t find any info on its sample rate. Can anybody help me with this ?
Best regards, xnemox1
I’ve never used these but they don’t appear suitable for realtime measurements for navigation. Rather, they’re for configurable yes/no determinations of relative positions. Is there a car in the blindspot? Enable a light because a shopper approaches a freezer at the grocery? Is the person waving up and down or left and right?
From the spec sheet (linked below):
The XM125 module is optimized for high precision people presence detection with capability to
recognize movement within configurable zones, motion detection, parking space occupancy detection
and level measurement for example in tanks or waste containers with configurable update frequency.
They’re certainly not intended or, indeed, possible to use for distance beyond a few meters. While long range sounds good, this device and others in the 60 GHz band are used because of the shorter range so that interference from other sources (like the adjacent freezer door) is reduced.
We discussed the 60 GHz band a bit here and there’s a nifty chart:
Spec sheet:
https://docs.sparkfun.com/SparkFun_Qwii … 133248.pdf
Table 4, page 13 has some insight. Note that the farthest distance benchmark is 2.75m and update rate is 10 Hz. This is the spec sheet telling you that 10 meters and 20 Hz aren’t supposed to work. There’s always possibility and hope that something may outperform the specifications but this behavior can’t be counted on and may not follow from one device to another, may reduce life expectancy, derate another spec, etc. Sometimes my avocados have a tiny, almond sized pit which is nice but I have to buy them based on the assumption there’s a normal sized hueso inside.