UART data up to just 8 Hz?

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Joined: Tue Jan 22, 2019 1:59 pm

UART data up to just 8 Hz?

Postby TomonoriN » Tue Jan 22, 2019 4:19 pm

Hello, I'm Japanese university student.
I would like to use these devices with RaspberryPi3 on the robot to get its coordinate via UART.
In my program, RasPi gets bytes data from hedgehog and coverts it into Hex, then into Decimal number.
Successfully I can get and read the data of timestamp and coordinate[x, y, z].

However, there is a problem.
In result, timestamp values have always 125 [millisecond] interval, that means it works on 8 Hz, even though I set the system; location update rate:16 Hz+, radio profile:500 Kbps.

Have I overlooked anything? There is no sleep time or delay in the program.
Please tell me what should I do.

Sorry if my English is wrong.


Posts: 191
Joined: Sat Feb 06, 2016 4:03 pm

Re: UART data up to just 8 Hz?

Postby smoker77 » Thu Jan 31, 2019 4:21 pm

The additional limitation of update rate is time of flight of the ultrasound.
By default, maximum measured distance is set to 30 meters, so you can place stationary and mobile beacons up to 30 meters one from another.
In this case time of flight is close to 100 ms, and this limits update rate to ~10 Hz. Other things - radio traffic, time of calculation - reduce this rate to ~8 Hz as you see.
If your distances between your beacons is less than 30 meters, you can reduce the setting in submap menu in dashboard as shown on attached screenshot.

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