Thursday, October 17, 2013

7” Nexus Tablet as Instrument Display

I have been experimenting in building custom displays on a 7” Nexus tablet, from 10 Hz live data received through Wi-Fi from my master microcontroller. This short video taken while sailing shows how this looks like.


The Nexus tablet is powerful enough for the job, refreshing the screen 10 times per second with new data.

 This screenshot explains what is going on in close hauled mode:

There are 3 thick needles, each one accompanied with a smaller one and a corresponding number of the same color.

The blue data is for STW (Speed Through Water), the green data is for VMG (Velocity Made Good), and the red data is for AWA (Apparent Wind Angle). The small needles are the instantaneous measured values, refreshed 10 times per second. The thick needles and the corresponding numbers are dampened data (moving averages over 1 to 5 seconds, recalculated 10 times per second by the tablet). The damping period (4 s in this screenshot) is adjustable on the fly by sweeping a finger on the tablet up and down.

The small black circle is a moving target (depending on current True Wind Speed), which represents the optimal AWA for best VMG.

The next screenshot is for downwind mode. Here, the red needle represents TWA (True Wind Angle), a more useful information when flying the asymmetrical spinnaker.

There is also a night mode available, created by inverting the black and white colors.

The tablet is not bright enough to be used as a fixed display in the cockpit, but very usable as a personal display, like the tacticians in the last America Cup.
Ben Ainslie (Oracle Team)
Ray Davies (Team New Zealand)