I thought I’d share a little detail on the Syma X1 quadcopter I picked up as a practice tool and toy from Amazon. There are 3 models you can choose from but they are all the same except for the vacuum formed canopy. You can choose from a UFO, a spaceship, or a bee. It is almost purely aesthetics that separates them. One surprising difference is that Amazon often has different prices for each one (although only by a dollar or two.) It seems that the bee model is always a little higher priced than the spaceship, with the UFO floating in between the two on a daily basis. Strange, but there you go.
What do you get for your (approximately) $36? Well, here is a pic of all the things in the box. There is a LiPo battery with a USB charging cable, the controller, a manual, spare props, and of course the copter itself. The manual is pretty challenging. It is not just that it appears to have been the result of a liberal use of Google Translate, it is that it is missing a couple of extremely key elements. As you can see if you read the comments on Amazon, the first issue is that the manual doesn’t tell you that immediately after inserting the battery you must put the copter on a level surface. The gyros only calibrate on initial power up and if you’re holding the thing in your hand (as I and many others have done) it gets a bad idea of what level is and the result is a copter that can’t fly straight. Second, the transmitter and the copter sync to one another on power up and timeout if you don’t manage to get them both turned on within a second or two of each other. This results in a bit of a frantic shuffling as you insert the battery in the copter, quickly set if on level ground, then flip on the controller power so it can sync. However, once you’ve done it a few times you realize that you have more time than you feared and it really isn’t that hard.
The controller takes 4 AA batteries that from all reports will last a long time. It makes sense, the controller itself is pretty simple and doesn’t draw more than about 5V to power its radio and small set of chips. The copter battery is a single cell LiPo which yields 350mAh at 3.7V and has an integrated JST-style connector. It is good enough for about 8 minutes of flying per charge and takes about an hour to charge between flights. The USB charger is a very simple device that relies on the battery itself to stop charging. Don’t use this USB charger with other batteries as it will happily keep charging them until they catch on fire. Like all LiPo batteries, you have to know how to use them safely. As it is, I have charged this battery a dozen times and never did it get the slightest bit warm and has cut off on its own every time. I would still watch it carefully though and certainly not leave it charging overnight.
The flight controller on this little toy is overall very well done. The picture here is hard to see, but it has a simple pair of dual N-channel MOSFETs as speed controllers (the part that transfers digital throttle commands into variable current to the motors), a 2.4GHz radio module (that’s the big silver part plus the A7105 chip to its left), what is described as a 6-axis gyro chip, and what looks like a custom chip that Syma is using to handle the real flight control duties. I don’t know what this part is, but the firmware in it seems overall pretty good. Most people have good luck getting the thing to hover easily indoors (no wind) and enjoy reasonable control in most conditions.
How is this to fly? It’s a great deal of fun. The controller can operate in Low or High modes which pretty much translates into “less sensitive control” and “more sensitive control”. It also has a built-in trick which will flip the copter in any direction automatically (this is the strangely titled “Eversion” feature which seems to be a casualty of faulty translating). Push the right shoulder button, then pull the right stick in any direction and the copter will roll in that direction. It needs about 2 cubic feet of space to do the trick but because it has altered its momentum you don’t want to do that too close to the ground or people. Regaining control after the flip is pretty easy so its a safe maneuver in most environments. I did notice that it was a bear to control in high winds. Most of that came from the wind resistance of the plastic canopy. When I removed it I noticed it was much easier to fly. The canopy also created a surprising effect. When wind comes at the copter from below (not uncommon when near a building) the canopy acts like a sail allowing the copter to gain tremendous altitude quickly. In fact, I had it floating at nearly zero throttle more than once with a decent wind gusting up from below.
One great feature of the copter is its weight. Ready to take off, the thing weighs in just under 70g. That is super light. No wonder it can do flips and zip around with easy. It also means that when you crash you aren’t really likely to hurt it. I have gotten into the habit of going to zero throttle any time I lose control and even though it has hit the pavement after falling for over 10 feet the device has never been damaged. It is good to remember Newton’s second law in these situations and that a light copter keeps the force in a crash to a minimum. I can’t imagine what crashing a 1kg copter is like, but it can’t be pretty.
I have to confess that this is my second X1. The first one sailed away over my house and was lost. I sure wish I had some idea where it went, but while I saw it tumble from the sky I was never able to recover it. I consider it a learning experience – don’t let the thing get too far away or too high. I also have experienced some strange control interference in a couple of occasions. 99% of the time the device has crisp response, but more than once I found myself wondering why the stick didn’t seem to control the device. I think this is most likely caused by the relatively weak transmitter in the controller, but it is hard to tell.
I also have to tell the story of how I tested its ability to be a submarine. I was flying around the back yard and it got too much sideways momentum while I was landing and it slid right into the swimming pool flipping over onto its back. At first I figured I had gotten lucky because it was floating on the surface, the canopy acting as a boat. But as I went to grab it I accidentally pushed the throttle on the controller with my other hand and much to my surprise the submerged props happily drove the little copter right under the water where it sank to the bottom about 4 feet down. I was frustrated and ran for my pool net. As I fished it out, I was surprised to see that the little red LED continued to operate and all the way to the surface and even after I shook it to get most of the water off. I quickly removed the battery and set it on my table to dry. I was hopeful it would survive and lo and behold, it did! I’ve flown it several times since then with no adverse effects from the dunking. Now that’s robust design!
Overall, I highly recommend this little toy. If there is a downside it is that the 8 minutes of flying time goes by too quickly making me wish for more batteries or a faster charge. I’ve ordered some extra batteries which will help. However, my next step is to mount a tiny keychain video camera to the copter and fly it around recording to see how that will work. Check back soon!