DVX synchronization with Optitrack motion capture

[Gianluca Amprimo]

Hello,

we want to synchronize an Optitrack motion capture system with a DVXplorer Lite camera. We are exploiting the ESync device of Optitrack to generate a signal to supply as SIGNAL_IN to the event camera, together with the GROUND. However, the camera seems to not detect the rising edge of this signal, since only few spurious trigger events are reported in the saved aedat file. The signal is a train of pulses at 30Hz, where the rising edge is the start of the acquisition of the motion capture system. We would like to know when the motion capture acquisition is done in the stream of events taken by the DVXplorer camera.

According to the guide and some answers here, also Vdd should be provided in input, together with SIGNAL and GROUND. However, in these first experiments we did not supply this voltage, could this be the issue? What should this Vdd value be? 3.3V or 5V or other?

Moreover, are there specific settings that we should pay attention to have in the DV software for this type of synchronization?

Thanks for the support.

Gianluca

[Luca Longinotti]

Hello,

correct, if you don't provide the VDD reference you'll get no or spurious detection results.

The detection circuit is electrically isolated from outside, so without providing both GND and VDD reference for the incoming signals, it won't work (or just randomly).

VDD can be anything from 3.3V to 5V, it simply has to be the same as the voltage of the SIGNAL_IN signal. If you generate this externally and not from the same source as the signal/GND, you'll have to short all the grounds together so that the voltages are references to the same ground. Simply supplying 3.3V from some random voltage source doesn't solve anything if it's not in relation with the signal.

Hope this helps, have a nice day!

-- 

Luca Longinotti (llongi)

Head of Embedded Platforms

iniVation AG - https://inivation.com/

Zurich, Switzerland

Office: +41 44 500 32 14

[Tobi Delbruck (INI)]

I think at least Gnd needs to be on the same cable, otherwise ground
loop on USB ground connection can cause spurious voltages.  But I'm not
familiar with the external input events on DVExplorer camera.