Wednesday, May 31, 2017

New DJI props arrived - noticeable quality improvement.

After the inverted faceplant into the driveway gravel that my drone made a couple of days ago,  I needed to replace my stock UPair props, I found these DJI props on Amazon.  

When they arrived they were all 13.0 grams +/- .05 grams,  the variance in weight between the props was minimal and the quality difference appeared noticeable to me. 

All four were in balance though I did add a 1cm square of cellophane tape to one blade but this is considerably less than the stock UPair blades that came with the quad.

I had over 80 successful flights on the last set of stock props and they would have lasted longer had not I rearranged my driveway with them.  Hopefully I'll get as much life out of these DJI props. I ordered another set of these sames props today.  It looks like a great buy at $13 for four of these.

Update: June 18th - I think that the noticeable improvement in quality of these props is what convinced me, without actually seeing one, that the DJI Phantom series was a quality build.  Now, actually owning one, I'm very glad to have purchased one.  The Phantom 3 Professional is an incredible machine!

Monday, May 29, 2017

WOW! That was interesting!

I just finished my strobe modification and went outside to fly.  I thought I'd be extra careful and at least try to calibrate the compass.  After all, I had the quad taken apart completely, taking pictures of the PX4 board and USB connections.

It went together mostly as expected but because I've added several new wires to the fuselage and some of that 20ms - 1A pulses for the new strobe lights, I was a bit cautious.

The quad started up normally and I chose PHLD (Position hold) with 15 satellites as I've had 75 successful flights prior to this mod so I thought everything would be ok.  Still, I was being cautious.

A raised the quad to 2 meters and watched it's position holding ability, which promptly stopped working, if it ever started.  There was no appreciable wind but the quad didn't hold position at all.  From experience, I switched to Altitude hold mode to disengage the GPS and attempted to land the thing.  It was everywhere and I was losing it quickly.  I wish I had a video  to review but it contacted the ground at a higher than normal rate of travel and flipped over.  Great!  Now my precious UPair One is chewing up the gravel in my driveway, inverted, and it won't shut off!  I have to pick it up and humiliatingly shut it off with the battery power switch!

What happened?...

Truthfully, I'm not sure.  I took it back into the shop and inspected the propellers (they were chewed up from the gravel in the driveway),  I tried to do an ESC reset as Olaf at DfL talks about, but it didn't work on my PX4 board.  

Well, I degaussed it again using my 40 year old home made degaussing coil. After sanding off all of the huge gouges on my props from the driveway, I tried flying again.

It worked!..It just worked!

I started the motors and they idled as expected.  I gave it throttle and it rose 2 meters and stopped climbing as I expected.  I reached out to hold it and made sure  it couldn't fly away.  Almost reassuredly, it hovered where it should.

I don't know if this is truly the degaussing working, but it seems to.

After further research, it appears that this degaussing question has come up alot on drone forums.  In this DJI forum, there is considerable questioning about how to do this and what tools to use.  Based upon my experience degaussing television picture tubes in a previous occupation, I'll write up my recommendations about how to do this.  

Sunday, May 28, 2017

56th Flight - Heiligenschein

1.54km east to the aqueduct at about 5pm.  Strong Heiligenschein at the quad’s shadow, even from 100 meters high. Flew south towards the powerlines then directly home.  Steep full throttle descent from 100 meters altitude to the landing.

55th Flight

My friend Mike came over and I let him fly this flight.  Autolanding RTL. Another convert because of GPS technology!

53rd Flight

Late afternoon  Departed to the east and turned north and flew up the road a bit at 100m altitude. Flew back down the street at 100 meters to keep the noise to a minimum.  Landed from the South over the shop. This is 1km from me. I installed the 600mw VTX a couple of weeks ago and it's really working well. I ordered a couple of clover-leaf antennas from aliexpress a couple of weeks ago. Turns out that I should have read this article from D4L before I bought them. As it turns out, I bought an SMA Male when I should have purchased an RP-SMA Male. Oh well, another two weeks for new antennas from China!


52nd Flight

I Flew 2.81km north towards a nearby radio tower.  The quad flew very well, great tracking, speed and controllability. I felt like this was the limit of the UPair One's range, the 600mw 5.8Ghz FPV transmitter was pretty snowy at times but the control transmitter also was getting to it's limits. At the antenna, RTL mode was auto selected once or twice and I decided that returning to home was a good idea. This distance is about 2 Miles which is pretty darn good in my opinion for a $295 quad.

 51st Flight.png

50th Flight

I would say definitively that the degaussing worked!  There was no tendency to toilet bowl on two successive stops in position hold.  I flew 1.1km North and stopped a couple of times along the way Even in windy conditions!  Very stable!  Even that tendency to depart to the right on takeoff seems to have cleared itself up!   Note: I also discovered that descending at full left stick down will not shut off the motors while you're in the air, but watch out for VRS (Vortex Ring State) on descent.  Later confirmed that there is a “landed” state in the PX4 board that allows the rotors to shut off.Flight Photo_0013.jpg
And lastly, I exposed some neodymium magnets to the alternating magnetic field of the degaussing coil after a friend of mine asked how badly the degaussing demagnetizing my motors?  Hmm, I didn’t think of that!  After 15 minutes of exposure, the unprotected neodymium magnet didn’t appear to have any loss of magnetism.  It must have but I couldn’t detect it without instrumentation. Neodymium magnets have a very strong bond!

49th Flight - Toilet bowl looks better?

Windy, about 15-20mph winds from the north.  Used the old TV degausser that I built 40 years ago on the drone.  Covered each motor and each leg and then pulled the degausser away as I would when degaussing a TV screen.  This flight had NO toilet bowl effect even in the wind!  Could this be the issue that I’ve been seeing for the past several flights? I'll need to test this some more but it looks promising.

Update: After thinking about this a bit, it would be much better to degauss my screwdrivers/tools before using them around the screws of the compass. Also, you can use transformer or even a soldering gun to degauss tools. Just start and stop the magnetic field a large distance from the item to be degaussed (1-2 meters), bring it close to the tool then move it away from the tool before shutting it off. You don't want to collapse the alternating magnetic field near the tool otherwise you'll magnetize it!

Update: After hundreds of flights without the 2.7k camera or gimbal attached to my UPair One, I have experienced absolutely zero "Toilet Bowl" events with my UPair One. Now I'm thinking that the problem I was seeing was being cause by taking off from my driveway with rebar embedded in the concrete. The only problem that I had on takeoff was caused by setting the UPair on the trunk of our Toyota Corolla. The metal certainly made this UPair act uncontrollable!

48th Flight - 3 hrs 30 minutes total Flight time on the UPair.

I have a bit over 500 hours logged as pilot in command in aircraft and 3.5 hours now flying my drone.

My 48th flight of the UPair began at Sunrise to the east of the house.  It was very calm and I distanced about 2km around the aqueduct and back home.  Some constant roll in artificial horizon with the joystick pointing straight up.  In a no wind situation I would expect that to be level.  I’ll need to research this. However, the quad didn’t power down on landing causing it to keep moving after touchdown and me to reach for it to shut it down. When I captured the landing gear, it corrected by pitching towards me and I caught the right-rear blade on my forearm causing two minor cuts.  Note to self: If this ever happens again I will raise the quad to about 2m and catch it in the air.  This is the second time that it didn’t power down on full throttle to zero position.  It seems like it hasn’t sensed that it’s landed so it won’t shut off.

Saturday, May 27, 2017

Android FPV Receiver records MAV data with FPV video.

The next addition was an FPV receiver for my Tablet & Cell Phone.  The Usmile 5.8G 150CH FPV Receiver UVC Capture Card looked like a good solution so I picked this up on Amazon, at least at this point in my understanding of the hobby.  I first tried it on my Samsung Tab S and then tried it on my Galaxy S5.  Both work fine and I found that my cell phone was a bit easier to lug around.

I have another FPV receiver on the way and will evaluate that as soon as it clears customs and I recieve it in Colorado.

47th Flight - 1435 meters with good FPV control.

What is the legal distance from a communications tower in the US?   If you are aware of the rules regarding drone clearance from a radio tower, I'd like to know.  I found this on a DJI forum:
"Until you bump into it.  Generally most radio towers, especially communications, broadcast radio or TV will have no effect on the Phantom until you bump into it or a guy wire. There are some terrestrial telephone repeater towers that operate in the microwave C-band which includes the 5.4-5.8 GHz band for IEEE 802.11a Wi-Fi. These are the ones with the antennas that look like big bass drums or strange horns and they could cause you a problem if you fly through the beam."

So the 600mw VTX mod is good to 1500 meters so far!

39th Flight

C:\Users\Jack\AppData\Local\Microsoft\Windows\INetCache\Content.Word\vlcsnap-2017-05-23-11h12m06s979.png Flew south over the 115k power lines to the oil storage yard.  

This flight was 631 meters away from my departure point and I was concerned about the influence of the high tension power lines below so I gave them a wide berth. Staying below the 400 ft agl altitude required in the US, I flew over them at 121 meters (396 ft).

I will often pre-plan my flights using Google Earth. It's a wonderful tool to pre-determine the distance required to fly to an object. Now that I can record the FPV video along with the MAV specs, I can better track my flights.

My first encounter the "Toilet Bowl" effect.

Noticed some toilet bowl effect while in PHLD (GPS Position Hold). Not sure if I noticed it before taking apart the quad to fix the motor.  Update:  I’m thinking now that my tiny screwdriver may have magnetized the screws holding the compass to the landing gear?

I switched to altitude hold mode and moved the drone forward to stop the oscillation but I didn't like my normally rock steady quad moving about on it's own like that.

My research indicates that the UPair One V4 isn't supposed to require compass calibration. I haven't hooked it up to QGroundControl yet, still waiting on confirmation of the external usb port pinout diagram.

Friday, May 26, 2017

UPair One motor repair.

After about twenty flights, I noticed that the right-rear motor started to have about 1/8 inch of free play when pulling on the prop and during motor shutdown, this motor would stop noticeably sooner than the other three.  This was the right-rear motor. I had read some stories about the Upair One falling out of the sky now and then and was worried about this motor losing a prop.

I disassembled the quad and then disassembled this motor and found that the set screw mounting the shaft to the rotor was loose and the shaft was working loose or the screw was tightened against the round part of the shaft instead of the flat point that is designed to hold it in place.  After inspection, this motor appeared to be ok, so I swapped the brass washers at the base of the motor. (The one with the small gouges in it) so it had a smooth surface to contact the bearing on the bottom of the stator.  The motor rotates as freely as the other three motors so I reinstalled it and reassembled the quad.
UpAir One V4 motor disassembled.

Wednesday, May 24, 2017

I have an electronics background so the idea of modifying my drone is very appealing to me. The UPair stock 200mw FPV transmitter is something that is often modified and this was one of the first modifications that I attempted.
Wolfwhoop W831 5.8GHz 40CH 600mW Mini AV FPV Transmitter for Aerial Photography

I replaced the stock transmitter with the Wolfwhoop W831 600mw A/V FPV transmitter (5.8Ghz 40Ch - Amazon Link: It came with a plug and wiring on it's side and I cut the existing power, ground and video wires feeding the transmitter. I soldered the connections and added a bit of shrink tubing and it worked great. A very easy mod. After powering on the controller and quad, a few clicks of the 5.8ghz channel selector on the new vtx and all was working as it should.

Tuesday, May 23, 2017

Second flight - Oops!

Same as the first but I decided to control the landing instead of using RTL.  I missed the white board I was using as a landing zone by 6 inches which caused the quad to tip a rotor into the sand before I was able to shut it down.  A motor got plugged with a few grains of sand but I was able to blow it out with the shop air. It appear to clean up just fine but I continue to keep an eye on it.

First Flight of the new UpAir One

Basic control evaluation.  I was very impressed with the ease of control.  After 5.5 minutes, I selected RTL and the quad shot up to 15 meters as it’s supposed to do.  I read about it in the manual but it was still a bit of a surprise.  It landed within 1m of the takeoff position, but I forgot about the horse’s reaction and I was a bit concerned about how he was going to react to the new noise in his pasture.

In the end, it turned out just fine.  Archie has learned about the new noise and it doesn't seem to bother him and I've had about 90 flights on the UPair One so far.

Monday, May 22, 2017

My third drone - a new UPair One (V4)!

5/5/2017 - Received a new UPair One as a Birthday present this year.  I've owned a couple of smaller drones, the $30 versions that you fly around your living room and crash a lot!

Honestly, I couldn't figure out what all of the fuss was about.  My first quadcopter didn't have a camera. I could fly it around the house but it was too small to fly outside in any kind of wind.
 Well not you and I since I got my UPair one, and you know better!

My second drone had a camera.  The video quality was pretty bad and the flying was difficult.  Because the craft was so small, I had a very hard time controlling it at any distance at all. Here are a couple of videos that I took with my second drone.

I think this is what many people experience and think about when someone talks about a quadcopter these days.