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thotro / arduino-dw1000

A library that offers functionality to use Decawave's DW1000 chips/modules with Arduino.
Apache License 2.0
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Negative Distance #121

Open belforti opened 8 years ago

belforti commented 8 years ago

Hi,

Thanks for sharing this project. I put it together using two Arduino Pro Mini 3.3v and get negative distances in the 4-digit order when the nodes are about 1.5mts away. I am powering the DWM1000 from the Arduino's Vcc pin since it can handle up to 150mA, and am not using any cap. Any debugging suggestion is greatly appreciated.

Thanks, Gabe

jjviscomi commented 8 years ago

This is most likely an overflow error.

belforti commented 8 years ago

Thanks. Strange though since I'm using the examples from github and typically you would get a sporadic overflow error, not a constant negative distance. -G

On Wed, Oct 5, 2016 at 2:11 PM, Joseph Viscomi notifications@github.com wrote:

This is most likely an overflow error.

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jjviscomi commented 8 years ago

Did you calibrate the device or just run it ?

belforti commented 8 years ago

Joseph,

Thanks for your feedback. I ran it with 16384 (or 245ns) as TX and RX antenna delay value, which is the default value. The problem is that the system shows a distance of about -4500 mts, which means that even with the full antenna delay value (65535) the system will never show a real distance value. According to APS014 (page 6) the accuracy with no calibration is 30cms... not 4500 mts!

I did some testing adjusting the antenna delay values with another pair of DWM1000 and was able to find a calibrated value that would allow me to work within 40cms accuracy. However, after I saved the code and reset the boards, the measurement were again completely off by several meters, even if I left it running for a long time to stabilize temperature. Temperature drift cannot account for so many meters according to the specs.I also added some extra decoupling caps in case there were problems with the power source, but nothing changed.

I can try to do the full calibration with three DWM1000s as explained in APS014, however, I don't want to waste my time if this will not be the reason for such an unstable measurement.

Best, Gabe

On Thu, Oct 6, 2016 at 3:10 PM, Joseph Viscomi notifications@github.com wrote:

Did you calibrate the device or just run it ?

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jjviscomi commented 7 years ago

@belforti I am curious if you resolved this? The APS014 specification of 30cm is for the EVK1000 specifically. Which example ranging code are you using, TWR or TDoA?