Any fix for the Syma X8 altitude-hold models "sudden shutoff"?

authormoreau

authormoreau

New Member
Just wondering if anyone had found a solution to the problem of the Syma X8 models that come equipped with altitude hold suddenly shutting off the motors if you accidentally hold the throttle back just a tad too much for a couple of seconds?

Sure, it's a terrible design on Syma's part, but hoping that some entrepreneuring person out there has figured out a way to disable this horrible method of killing the motors and perhaps re-rerouting it to a separate switch so that you wont constantly crash your X8 when trying to come down quickly in bad wind.
 
I haven't got the AH board or controller in yet and it's gonna be a few weeks I think, but I'm sure there is a way to make sure throttle below 5% or whatever percent shuts off isn't ever reached. Although since I'm unsure of how it works right now, it may also hurt the landing or shutoff procedure.
 
This is basically the same reply I gave on another thread...a few weeks on and it is still working so long as we are strict about the calibration every time, when we forget it drops again.

We are trying to figure this one out for ourselves too. We have a pair, X8HC and X8HW - we fly them together and were suffering from the the motors just cutting out at "inappropriate moments". Sometimes one would suffer, sometimes both withing minutes.
We tried all kinds of experiments to find the trigger of the event. Taking them real high, pulling stick full down for long periods, no problems and many other theories we had.

What we settled on as a theory follows. Is it that the internal barometer that measures the height may be telling the micro controller the difference between being on the floor and the throttle pulled down for 3 seconds that turns off the motors, and it being 3m in the sky and then not to do the same?
We have found that before every flight calibrating the quad gyro with the two stick bottom right sequence seems to keep it from happening (google it). It may be the gyro calibration is merely causing a knock on of fixing this by some indirect software quirk, but for now we have not had any cut outs since doing this from having them lots. Again your mileage may vary, but passing on our experience for you to try! So after switching on the drone for a session from any new position, calibrate the gyro then go flying.

We often fly around a sloping field and move from top to bottom or bottom to top, meeting the drone there, the height is significant over length of field, so wondered if this may be confusing it knowing if it is on the floor or not too. Also found calibrating at the middle height of the field, taking off and flying the drone below the level we are standing at leaves this more prone to happen.

Good luck.
tim.
 
Sorry, tried Googling "two stick bottom right calibration" and came up with nothing. Interested to know how this works.

Also interested to know how often the cutouts were before this trick and how much flying you've done using it and how effective the fix seems to be. (helps it happen less often, or has completely eliminated the issue 100%).

You have two of them so if it's working well for two units you would have to think it's a fairly effective fix.

Thanks!
 
I should also mention that I read a post about cutouts with left banking and now that I think of it most of my cutouts happen when doing a hard left bank. Did you experience that with yours?
 
My son and I go out flying in the field out front and some times other locations together, about four times a week, with three batteries each per quad.

Before finding this technique they could regularly (several times a session) drop out the sky, but not predictably. The pattern often was after taking them really high and bringing them down hard would cause the issue (no banking). But it could happen quickly after lift off too whilst messing around. We saw many posts with theories and tried most of them out, but decided there was no pattern, like the banking idea.

I have not had mine drop since, other than a few times where I can pin it back to not doing this calibration or having moved up the field and flying below the level we are started at, standing looking down on the drones from higher up the slope.
My Son has had a few more drops than me, (again not many really) but he is into FPV racing drones, so pushes the envelope much more than I do and hits it on the ground more. So some of these may be due to other things like straw in the motor gears or loose battery etc. One of the HXT connectors on one of our batteries had no solder on it, was just pushed into the connector, I discovered this last night, so that might have been root cause of a couple of his fails, and motor has at failed a few times catching broken guards and thus safety cut out.
One X8HC and other is X8HW both experience same frequency of these drops I would say.

I'm not saying this is the cure - merely what my anecdotal evidence is. I don't even think the calibration is the actually curing it, perhaps it is just a byproduct of the calibration resetting some other values in the controller board that helps prevent this occurring.

Switch on controller, do the usual up down to bind. Then before going to start the motors, make certain the quad is perfectly level and facing in the direction you want the headless to go (away from you). Now bring both stick to bottom left corner at the same time, the quad should respond with some flashes after a second or so. This calibrates the gyro for what is level. Now release the sticks and bring them down to the bottom left corner. Again the lights should respond on the drone. Release the sticks and you should be good to lift off. This should reset the headless bearing, I do both each time I start a new session, or move location to higher or lower location in elevation. You can do it after landing and turning the rotors off too, if you choose without having to restart the radio transmitter.

I stress that I'm just adding to the mad theories and ideas, but it seems to work for us and it feels like a logical explanation to me.

Regarding your banking idea, could this be a different issue, as if you have guards on, they can flex up (especially if they have hit the ground a few times) and foul the blades when banking hard, that can cause the motors to sometimes cut out as it thinks its hit something.- just a thought.

Tim.
 
No guards, and I've read at least one other person say they had the banking issue.

So lower left on both sticks twice in a row to calibrate everything?
 
So at least that eliminates that theory!

Lower right on both sticks, release, then lower left on both sticks should is exactly what I'm doing before each flight.

I'd like to think it works, or I'm wasting my time doing it each time! - do update us

Tim.
 
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