My aversion to more sensors

The PC World mention, along with some recent comments got me thinking about why I lack interest in adding an altimeter / magnetometer / GPS / remote control to HoG.  After all, it’s the obvious next step.

I have the sensors already, and none of the above would add much in the way of overheads to the code processing – perhaps only 1Hz polls of the GPS, compass and altimeter fused with the existing data from the accelerometer and gyro about orientation, direction and speed feeding into the existing flight targets.  All relatively straightforward.

Autonomy vs. remote control was purely a personal decision based upon my ineptness at controlling machines with joysticks.  I stopped computer gaming with Half-Life2 2 when I was within seconds of the end and yet  lacked the hand-eye coordination to win that final battle to stop the launch of the missile / rocket / bomb.

It’s a combination of time and testing that is the biggest problem.  Up to now, all testing happens in the back garden – it now takes me less than 5 minutes to run a flight, and get back indoors to analyze the diagnostics.  Even when the weather is terrible, those 5 minute slots exist virtually every day.  But with GPS movement tracking resolution of 10m, the garden is nowhere near big enough to test autonomous path tracking – just too many high stone walls to crash into.  I could move testing to the village play park a hundred meters down the road, but it’s called a kids play park for a good reason.  I could move into the fields a couple of hundred meters away, but that’s just far enough away that time steps in – to-ing and fro-ing between the fields and the “engineering lab” (home office) would just be too inefficient for the limited time available due to a full-time job and two kids under 7.  Oh, and the farmers probably wouldn’t appreciate HoG scything down their crops or sheering their sheep!

So I settled on short term autonomous flights within the bounds of the back garden.

Having said all that, I’m off to the kids’ play park tomorrow during school time just to see how long HoG can maintain a stable hover with limited drift, and perhaps add some horizontal movement to her flight plan if all goes well.  Weather forecast is good, sunshine and only a gentle breeze so hopefully I’ll be able to get a longer video of what she can do!

2 thoughts on “My aversion to more sensors

  1. Set up an array to throttle the sensors to match what you need for the mission the device on. While not a UAV I worked with a vehicle tracker that we used the extra sensing lines to count vehicles, determine their direction and speed by hooking up two light detectors and writing a few loons of code one night so a client could do a demo on 2 days notice.

    If you don’t use the extra sensors throttle them way back or turn them off with software. You may find they are just what you what next week.

    Good Luck
    Gordon

    • Good advice! A lot of stuff in my office was once redundant but is now useful because I hadn’t thrown them away! The extra sensors are not used by the software at the moment, but will still be there if I need them in future, just as you suggest.

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