Comments

• 

  Dr Mike Black June 30, 2012 at 3:10pm

  HI all,

  I have to agree with Harry on this, if the GPS is locking, but the AP is not seeing it, then its def a protocol/baud rate issue.

  Im sure you are aware, but Sirf is 57600baud, ublox is 38400, so if the AP baud rate is not set to 57600 they are never going to talk to each other. If memory serves, mine is still set to Sirf (EM406 from the dim and distance) the AP locked up well, but again if memory serves AP 2.4 and on was written for ublox and ported to sirf, but not fully tested...you will have to forgive me, but this rings a bell in my mind.

  (reason being EM406 only has an update rate of 1hz, so we were encouraged to move to the ublox)

  On the subject of the ublox, i just wanted to make absolutley clear, that i dont hold DIYd responsible for the GPS issues, this is a manufacturing issue, im sure that DIYd like us, buy in and sell on, its not feasable or practical to test each unit.

  However, having said this, the GPS issue has caused me an absolute nightmare this week.

  its so hard to detect code changes, when the constant (gps) is now a variable.

  In my mind the GPS should perform in the same manner most of the time (there for a constant) however, this is not the case.

  SO...after concluding all my tests, i fitted a known good one to the AP, and wow....flew like a dream.....now for the nightmare...

  all accidents are the operators responsibility,...Having set my ALT to 170 feet, of we went.

  what i had forgotten is that on our other field there is a line of trees around the 100 foot mark (most trees here in the UK are about the 40-50 mark) Anyway, flown 3wp's and on its way back to me, it crossed the line of trees an djust clipeped the very top and got stuck!

  Given the height of the tree, we couldnt climb it, and realised that a very small branch was holding it up, SO....

  (I dont suggest any one else tries this) we shot the branch away, hopefully allowing the aircraft to fall.

  We managed to do exactly that, and with out hitting the AP, however, the canopy was thicker than expected and it got wedged another 5 or so feet down from the top.,

  So, after the proper application of marquee poles and joiners we made a pole around the 90 foot mark, 5 blokes, me included 2 guide ropes and managed to feed the pole up through thetree and knock it out. (4 hours to do it though :(( )

  downside, it smashed the top off the nice lovely GPS..

  to top all of this off, our FPV ship with the other AP1 on, got wing flutter at speed, and commited suicide...

  So not the most succesful week, in the grand scheme of things....

  @ Anwar, try setting your EM406 to NMEA @57600, and set AP to the same, the quality is low, but it will show the lock if the communications are there.(other thing that occurs, you havnt swapped the Rx Tx leads to the GPs have you? simple mistake but again it will never show as locked on Ap)

  
  @ Harry, how is your GPS beairng up with carbon under it? i was wondering if the magnetic field from the magnet or the underside faraday cage is affecting its performance? Just curios really.

  kind regards,

  Mike.
• Harry June 30, 2012 at 1:44pm

  GPS good!  Problems in the Ardupilot somewhere.  Have you tried a different version of the firmware, just to see it get a lock?  A version greater than 1.0 will use Sirf.  That could help isolate it to area of code dealing with GPS and bauds.
• 

  Anwar Ali Khan June 30, 2012 at 9:29am

  @ Harry and all, I have already checked the EM406 with SIRFDemo and the GPS is performaing perfect. 12 sattelites in view and 10 being used to fix (even 7 in view and fix with 3 sattelites inside the house). Using SIRFDemo I also realised that Sirf quality is much better than NMEA. Switching between Sirf and NMEA is just a matter of click (no wait for a week required). I have put the GPS now on Sirf mode, the red LED on the GPS gone to very dim, BUT still no success, because I don't get the blue lock LED at all. Its becoming now frustrating because taking all of my aero-modelling and flying time for nothing.

  If I keep the GPS_PROTOCOL as  'no GPS' (-1) then I get the blue LED blinking. If I keep it as 'Simulated GPS mode' (5) then the blue LED turns on without blinking but when I keep it as 'SIRF' (1) then no blue LED at all.

  I have tried previous codes also but the blue LED keeps blinking without getting to fix, althoug with the SIRFDemo it gets the fix within a minute.

  I don't find any more options, bad luck.
• Harry June 30, 2012 at 3:08am

  Heya Anwar, I've been thinking about your GPS and you could probably use your FTDI cable to get a direct serial connection to a computer.  Downside is you'd need to modify the GPS cable.  Sparkfun has the data sheet on the EM406 which shows the pinouts.  Dont get that part wrong like I did once and fried my first GPS, an EM401. 

  One more thought on running it in NMEA, I have doubts that the EM406 will run in NMEA @38400 but that's the speed Ardupilot needs.  So, if you have it @9600, the Ardupilot wont like that and never show a lock. 

  Sirfdemo would let you see for sure what's going on with it.
• 

  Anwar Ali Khan June 29, 2012 at 2:52am

  @Dr. Mike Black, so we are waisting our time because of the hardware related faults. DIY DRONES should ensure the quality of the products before selling them out. Thanks for letting us know. Probably it is the same with my GPS.
• Harry June 29, 2012 at 1:00am

  That's some good rambling Doc and thanks for the explanation on D6-D8.  I finally built my motor mount/GPS mount/Wing Hold Down.  The GPS will sit on top and is held by a big magnet embedded between 2 layers of carbon.  Here's a pic.
• Moderator

  Brian June 28, 2012 at 9:50pm

  Hey Mike,

  I second the request to continue.  It's good to see your posts as it's a motivator for me.  I have not flown my AP(l) since about February.  I had many hours of flight on the unit, my guess is about 75 hours of flights.  It was working very well for me then one day, it just started acting up and would not disengage the motor after switching out of FBW and into stabilized or manual.  It would work fine until I switched into FBW mode then it would do as stated.  

  Anyhow, being me I did not give up on the unit and toss it away, I simply took it out of the loop and started playing with my new platform getting that setup.  The ProJet Nitro-003 RQ11 Raven flies great so I'd like to get an AP setup and working with that plane but I also have a Stryker that I'd like to get flying using my older board.  I have one of the CO-Pilot sensors left (thanks again Simon!, for ripping it from my plane in mid-air, it was fun looking for it in the field) and an ArduIMU.  Not sure if the older ArduPilot will work with the ArduIMU so I'll probably use the CO-Pilot sensor on the Stryker and the IMU on the Raven.  I have not done anything on the delta but am interested in your work.  Also am interested in getting my mits on a big ol' delta.... Your's sounds interesting, you should have someone across the pond do a flight test for you! :)
• evilmacaw June 28, 2012 at 3:44pm

  Yes Please continue !!!! Dr Mike Black 
• 

  Dr Mike Black June 28, 2012 at 3:22pm

  Thank Mike,

  Just want to share this, I am totally into the APM/ AMP2 an di have many, but this little baby, teaches you that you have to KNOW what it deos and how it deos it. (Hoooge fun factor for me)

  And setup is everything, personally i think EVERYONE should have an DIYD AP MK2 from that, they will learn everything then eed to know about how they work, an what you need to be looking for.

  As soooper cool as Micheal Obourns planner is and the way it updates the AP, i think we could all use the grass roots AP lession and get dirty with it, THEN with APM1/2 the faults become easier to define, as you know where to look in the cood.

  Just my view, but personally i wanted to get AP1 working flawlessly before we start on the APM's , backgroung knowledge learned ready for the next project.

  If you guys are interested i will continue to post teh trial and tribulations of making AP1 work for us. I know there are so may still out there, but saldy not used..

  Let me know if you would like me to post my deranged AP meanderings.

  Kinds regard,

  Mike
• 

  Mike Boland June 28, 2012 at 2:53pm

  I am sure there are many lurkers like myself, and that was useful information, as I am currently having GPS, and with new product.

  Thanks for sharing