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Re: OP GPS can't change to UBLK
« Reply #15 on: May 22, 2019, 07:33:34 am »
I checked the pins on the main - none bent. Bad connection internally or dead io - hard to tell.

So I really don't need a separate RTB switch position? It will automatically do a RTB if I turn off the transmitter?
Is this a default mode?
I've never been a fan of having to do a unique arming sequence - but this is making me think twice about using it!
Thanks for all the help BTW. We've been using a bunch of Atom flight controllers in our experimental eVTOL planes and finally getting usable flight characteristics.

I lost a hang gliding friend recently - drowned. Rescue helicopters got to him too late. It's made me see the potential for our aircraft as potential rescue vehicles in an entirely new light. So I'm looking at what it takes to send destination coordinates - potential for automated response.

Re: OP GPS can't change to UBLK
« Reply #16 on: May 22, 2019, 09:28:09 am »
As I recall, the way the 16.09 code is written, you need an FMS position for RTB.  The position is really for failsafe and failsafe can be set different ways.  One way is RTB.  You wouldn't want it to RTB if you were flying it from a boat.  Position Hold might be a better option.  As I recall, it won't arm if FC failsafe selects a switch position outside the range of the switch.  I personally think you should be able to tell it "to use the 4th position of a 3 position switch for FC failsafe (e.g. RTB)".  I made that code change on one of my aircraft but eventually removed the change since I have many aircraft but don't need RTB setup on many, and I should really put it everywhere or nowhere.

There is a work around for the average user to get e.g. a 4th position on a 3 position physical switch.  It requires that you use RC failsafe (the receiver continues to send pulses, but those pulses are set in the RC radio to be what you want for failsafe when you e.g. fly out of range) instead of FC failsafe (where the receiver stops sending pulses and the FC detects that, and uses it's own failsafe settings as set in the GCS).

Tell the GCS that you have a 4 position switch, then set your 3 position FMS to select the first 3 flight modes and set RC failsafe for the switch to be past this range and select the 4th FMS position.  Usually this can be done by starting with 4 positions in the GCS FMS setup and your switch channel putting out the full range of widths (e.g. 1000 to 2000 usec) during setup (or manually).  Set your RC failsafe to the 2000 usec position, then reduce the switch channel endpoint from 2000 to something like 1675.  The switch should then put out something like 1000, 1337, 1675 for the 3 positions, and 2000 when you switch the transmitter off.  Look on the Input page to make sure that each position is safely in it's desired range (not on the edge).  You can do some math and careful setting to get it right in the middle of each range, but it's not required.  Careful when testing by turning transmitter off because some transmitters require all switches to be switched a certain way and the throttle to be zero before they will turn on.  You would probably want to turn these safety features off.  It wouldn't be good to be required to start up at zero throttle, etc.

Switch the transmitter off or fly out of range and you get 4th position.

Be careful about flying RC over any USA national park and a lot of other parks too.  That includes a lot of forests and beaches.  USA national parks are rabidly "anti-drone" with a rule that bans it in all national parks.  I don't have personal experience with it, but I remember when they enacted the rule about 5 years ago.  (Personal opinion follows.)  They are going to have to do a 180 on that before I will consider helping national parks with anything to do with RC / drones (SAR, fire support, wildlife monitoring, drone knowledge, etc.) that I would gladly do for free otherwise; and my father was a USA NPS park historian.  I understand that it's not good to have a bunch of quad racers screaming around and running into people, but a middle ground could be reached.
« Last Edit: May 22, 2019, 09:50:24 am by TheOtherCliff »