All posts by Paul

...has been travelling the world for more than fifty years; having lived and worked in five countries and travelled to many many more. He likes to write about his travels - present and past - along with his other main interests of Information Technology and Motorsport, and he adds a few general twitterings along the way. More info than you could possibly need is available by clicking the ABOUT tab in the top menu line.

The Drone Diaries. Part 9…

…And Then There Were Cows.



Last night I watched a drone review on Youtube. If I hadn’t, I would probably be too embarrassed to write this article. You’ll see why…

First; a quick recap…

Several months ago I ordered a Cheerson CX-35 from a company called Banggood. It arrived. I assembled it. And I had all kinds of problems getting the handheld controller to “talk” to the drone. Eventually I did something – I’m not sure what, but maybe the sprinkling of holy water helped – and it started working. So, I made a couple of short flights, just to learn how bad a pilot I really was, and then it stopped working again. Permanently.

Banggood offered me a 40% refund which I declined. Then they offered me 70% and said I could keep the drone. This I accepted as at least I’d have a good stock of spares.

So I ordered another from a company called Geekbuying. After waiting a month, and sending them several e-mails, they told me it was difficult to ship to Thailand. They offered me a full refund, which I accepted.

I think that’s where I left you in the last article. Then something unexpected happened…

The two refunds arrived in my account in about three days. Miracle. I was expecting three months. So I ordered yet another CX-35, this time from Lazada. I don’t think it’s a Thai company but at least they have an office and shipping facilities here. The price was higher, but they offered fast delivery.

I ordered on a Friday and was told I could expect delivery between the following Wednesday and Saturday. By Tuesday afternoon I could see on-line the order still hadn’t shipped, so I figured there was no way they would meet their target. But I was forgetting this was a domestic shipment, and in fact it left Bangkok Tuesday night and arrived Wednesday lunchtime. I was impressed.

But less impressed when I opened the box.

The drone box was inside another which was at least 50% larger and had no packing. So the drone box had been crashing around during shipment. Nothing was visibly damaged, but…

This one came partly assembled – well, more assembled than the first one. In completing the assembly – landing gear, camera gimbal, prop guards – I noticed several loose screws, and then several missing ones. Then I realized there were no bags of screws. And no bag of spare props. One screw holding a propeller had been cross-threaded and had stripped the thread in the motor’s spindle.

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Where’s the screws, and the spare blades?

This is not good, I thought. I figured it had either been assembled by someone who’d had too much Szechuan Chicken for lunch and really needed to be somewhere other than on an assembly line, or it was a pre-owned model that had been returned by its first owner. I suspect the latter.

twitterings drone diaries
I can recognize a new prop when I see one.

This is where the first drone came in useful, and after a hour or so of playing mix’n’match, I had something that might actually work without falling apart. I took it off to my favorite drone-testing field a couple of kilometers away. It’s the size of at least four football fields. Canadian, American, British, no matter. Pick one, and you’ll have a good idea how big the field is. So big that nothing could go wrong.

Isn’t this where you lost the Eachine E-50?

Yes, but that was so tiny that… Oh, never mind.

But on this occasion there were cows. It doesn’t matter, I thought, I can stay away from the cows.

My first flight was brief. Just a quick up and down to make sure it actually worked. It did.

At this point Farmer Somporn arrived. (Probably not his real name.) He seemed more interested in me than his cows, and watched carefully as I was more ambitious, and sent the drone up to about three meters.

At which point it decided to go visit one of the large bovine obstacles.

I pushed the throttle lever down to land it. Did it obey? Noooo. So I tried steering. Did it steer? Noooo. Narrowly missing one of the cow’s left ears, it headed for the beach … and the sea! At which point it suddenly decided it would obey me after all, and landed. Phew! (Kindly note that I studiously avoided making any bad puns about steers and cows.)

I wasn’t impressed. Farmer Somporn wasn’t impressed. After checking that his animals still had a full complement of body parts, he jumped on his kapchai and tootled off. Bert, drone and I went home. Liquid in green cans was needed.

Next day, not having a friggin’ clue what was wrong with it, I decided to do what I call a “bench test.” This involves putting the drone on a table, and holding it down firmly with my left hand while operating the controls with my right.

This enabled me to discover that when switching off the motors one prop was stopping way sooner than the others. That didn’t seem right. I also discovered how sharp the props are as one sliced a piece of skin off my thumb and left a nasty bruise. The motors are powerful. Damned powerful.

So a full strip-down was needed. All parts checked. Grease applied where appropriate. Then a rebuild, and more holy water. I’m talking about the drone of course, although I could probably benefit from similar treatment.

For testing, I wasn’t about to head off again to Le Champ de Vaches so I stepped out the front door and tested in the road. With houses both sides, I wasn’t likely to send the thing off into the sea.

Take it easy I told myself. A quick up and down. No problem. Take off, up to a couple of meters, straight down the middle of the road, turn around, back to me, and land without crashing. Brilliant. Do this four times. Brillianter. So I decided to pop in a freshly-charged battery and head to the field at the back of the house.

This has been freshly whipper-snippered. Long overdue. But that always makes me nervous, as anything living in the undergrowth, like snakes, spiders, scorpions, but probably not tigers, need to find somewhere new to live. My back yard is an obvious location. But I haven’t seen anything. Yet.

Anyhoo, I put the drone on the hard road ready to fly off across the field, started the motors, and increased the throttle to take off. At which point it scooted horizontally across the road, crashing into the kerb, knocking off the camera and breaking a prop guard. I just stood there in disbelief. WTF happened? It was working perfectly two minutes earlier around the corner, and now this. More liquid in green cans was needed.

And I needed to take a break and do something else for a few days. Or years.

Yesterday it was time for more stripping. But that scared the neighbors so I took apart the drone instead. Broken motor spindle, damaged props and other maladies. I’ll get to it.

So, back to last night. I watched an experienced drone pilot and reviewer tell us about his adventures with the new DJI Spark. If you’re not familiar with drones, well, DJI is like the Cadillac of drone manufacturers. I doubt any professional pilot would use anything else. So you’d imagine that – even though it’s at the bottom-end of the DJI range – the Spark would be totally bug free.

For five minutes I listened to what an amazing piece of kit this is. GPS sensors that can lock onto fifteen satellites for absolute precision control and positioning. Cameras that can sense the user so that the drone will respond to hand gestures. I can think of a few hand gestures I’d like to direct at my drone.

It can follow you. You can wave to send it further away. It does good quality photo and video. And you can hold out your palm so that the drone will land on your hand. Truly amazing.

Well, for US$700 including gizmos, I think you can expect something special. Okay, you can spend less, but then you don’t get gizmos like – the controller!

Then the reviewer explained why he had three of the things sitting on his desk.

One reason was to show us the colors. There’s five available. But the color is only on the top, so once off the ground, you only see its black bum. Seems a bit pointless. But perhaps its a status symbol. My drone matches my car, or nail polish, or something. But that wasn’t the main reason why he had three…

To my absolute astonishment the reviewer proceeded to describe the same problem I’d encountered. The first two Sparks he’d tried were “uncontrollable” “minds of their own” “almost lost them” etc. He’d been flying in a real football field and admitted that if he hadn’t been an experienced pilot, he would have lost them. The third, he said, worked straight out of the box.

It seemed unbelievable. You have to spend US$2100 in the hope of getting one that works?

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Look at the pretty Sparks … before they disappear.

But then, almost as an afterthought, he mentioned what, I think, is a crucial piece of information. He said that after changing batteries several times, the first two Sparks worked perfectly.

Ah ha. On both of my serious flying mishaps, I’d tested the CX-35 to make sure it was working properly, and then switched to a fully-charged battery. Could there be something wacky with the LiPo batteries? I know they are strange animals – prone to catching fire. I keep mine in a thick metal box. Perhaps also they have a habit of not producing full power straight after charging.

I don’t yet know the answer to that. I have to do more mixing’n’matching to make a drone that might fly, before discovering if it will. But hey, it’s a theory. I’ll drink some more liquid from green cans while I’ll think about it.