hand-catching the mini gone wrong. My fault or bad luck?

[Droning on and on...]

Today the mini drew first blood, my arm is pretty messed up.
I'm not sure what happened so figured some advice could be useful.
I was flying the mini outside, controlling it from a window of the first floor of a building.
When I was done flying, I brought the mini very close to the window so that I could place a flat hand about half a meter below the mini.
Then I pressed down on the joystick so that the mini would slowly land on my hand (I do this regularly).
Instead what seems to have happened is that the downward facing sensor had no clue my hand was there.
The mini therefore descended rapidly onto my hand, I got scared and pulled my hand back inside the window with the mini on it and then things got a bit out of hand (literally ) until I managed to shut off the engines.

Is the procedure for hand-landing that I followed not the right one? Did I just have very bad luck that exceptionally the sensor didn't spot my hand?

Some of the blades also got a bit damaged in the accident. This is the worst one, it seems to fly allright, but it now makes a different noise than the other blades when flying. I guess it's not too damaged to fly?

 

[THE CYBORG]

Ouch, don’t fly with that prop.
I was pretty confident I could hand catch my MP2 until it’s props were screaming close to me so I chickened out.

 

[dirkclod]

Hate that happened to you and not going to speculate what happened
but will say this yes change that prop and I have always with all mine
when I changed 1 I changed all. Might be over kill but I think off it as if I change brake pads on my truck I just don’t do 1 side I do both.
Have disposed of I can’t tell you how many props but is just what I do.
I want them all to be worn the same. It’s not like they cost much but
are about the most important component of the drone.

 

[SquishinStix]

Your approach isn't quite right.

Once the Mini is close enough, put your hand underneath it fairly close and wait for it to sense your hand and rise up. Once you've confirmed that it has sensed your hand, then descend onto your hand - even then, I always start slowly, I don't just hammer down the stick. Alternatively, once it senses your hand, you can auto-land using the phone screen.

Hope that helps! Unless I have a solid surface (concrete, wood, etc.) from which to launch and land, I always do it by hand to avoid dust/dirt/sand from being kicked up and haven't had any issues.

 

[Lurch003]

Flat hand- like feeding a pony! You don't want any fingers sticking up!

Go on, where's the pic of your arm?!!

 

[BokiFly]

Instead what seems to have happened is that the downward facing sensor had no clue my hand was there.

Did it rise up a bit before going down?
Did you hear a *bip* before going down (auto land executing)?
If the answer is "no" then from some reason Mini didn't saw your arm. Maybe your arm was not straight bellow Mini.

 

[ff22]

Have you been practicing hand catching before this attempt? I'd do it from ground level and no window until I was sure I had the method down right. Then move to the window attempt.

 

[DrizzyDrones]

i simply put my hand out i bend my fingers back so my palm is the highest point i keep it liken that until the motors stop... the bottom lands on my palm and shuts down

 

[SquishinStix]

Here's a link to the video I watched to learn how to do this:

 

[BadWolf1]

I pressed down on the joystick so that the mini would slowly land on my hand (I do this regularly).
Instead what seems to have happened is that the downward facing sensor had no clue my hand was there.
The mini therefore descended rapidly onto my hand, I got scared ...

Ouch. More sympathy from here. If the drone is on your hand and not shutting down as normal, grip firmly and roll it onto its back which will force a shutdown. (Pretty sure the shutdown will happen well before 90 degrees, but just keep the roll going ). I can't remember which video I watched which said practice doing that, but plan on doing a landing with shutdown. It would have saved one drone lost at sea and more than just your injury.

 

[Droning on and on...]

Thanks for all your helpful replies (and sympathy )

I wasn't planning on replacing the damaged blades, but based on your advice I guess I should better do so.

It cut your arm? If so that surprises me, I have made two stupid lunges to catch my mini when joystick mistakes sent it into objects in the house and I have taken straight on blows to my fingers and the inside of my wrist from the blades, they hurt and produced tingling and maybe very slight bruises but that was it, no cuts.

Yes my arm now has various cuts where blood was coming out. It also hit multiple fingers, where there is no visible damage, it is just as you said: it hurt and produced tingling.

In detail though I tend to (right hand) extend my fore/first finger to straight, cup my thumb up the right side of the drone and cup the third and fourth finger up the left side of the drone, my little finger is tucked out of the way. The drone sinks into the preformed cup.

I don't think I dare do that, out of fear that my upright fingers will hit the props

Once the Mini is close enough, put your hand underneath it fairly close and wait for it to sense your hand and rise up. Once you've confirmed that it has sensed your hand, then descend onto your hand - even then, I always start slowly, I don't just hammer down the stick.

Great tip, thanks a lot! Will use this procedure in the future.

Did it rise up a bit before going down?
Did you hear a *bip* before going down (auto land executing)?
If the answer is "no" then from some reason Mini didn't saw your arm. Maybe your arm was not straight bellow Mini.

The answer is no, so this seems to confirm that somehow, it didnt see my hand.

To mightypilot2000, incidentally in an emergency tilting the drone on its side will shut down the motors, I wouldn't suggest it as a routine method of stopping the motors but it does work

Also a very good tip, although when I'm in 'panic mode' I'm not sure I will have the clarity of thought to do this.

Here's a link to the video I watched to learn how to do this:

Thanks, I also used that video as inspiration.

Have you been practicing hand catching before this attempt? I'd do it from ground level and no window until I was sure I had the method down right. Then move to the window attempt.

Yes I've done hand-landing quite often.

For landing when I'm standing in a building behind a window I stick my arm out of the window and then land onto my hand because I'm afraid that if I fly it trough the window, the downward facing sensor might detect the edge of the window and move upward and into the ceiling. Any thoughts on this?

 

[GerdS]

I would NEVER try landing the Mini on my flat hand! Especially for me this would be very dangerous as I have bad eyes and would risk to position my hand misaligned, so the Mini could drop of my hand and injure me.

The safest way for hand-catching is somewhat different and I do this after each flight from the very beginning without any problems or injuries.

- Hover your Mini with nose directed to you in a distance of about 0.5m and a bit above your head
-Now grap the Mini between thumb and index finger shortly behind the gimbal and under the front arms, with your hand coming from the front
- With your other hand do a CSC command for stopping the motors. A lanyard attached to the remote makes that quite easy as the remote is then hanging in front of your belly and you have all fingers available for grabbing both sticks for issuing the CSC command

Doing it this way there is no need to hurry and you have all time needed to slowly and cautiously getting your hand into position for grabbing.

 

[m80116]

The bottom sensors can only reject the landing when auto-landing or cause an altitude increase before the forced-landing has been engaged.

Launching from a window involves many risks... among which catch-landing is minor, the most prominent being a fly-away for powering-up the drone in a distorted magnetic field area.

 

[Droning on and on...]

So I should simply avoid launching and landing from a window? The thing is that I have much better range from my attic than my garden... But I guess I could go outside and place it on a table and then go upstairs.
Concerning this damaged blade which some forum members recommended me to replace.

I let the mavic mini hover inside for 5 minutes or so, and then analysed the motor speeds:

The difference does not seem to be big right? Only 500RPM or so.
What's even more curious is that the most damaged propellor (the one I pictured) is on the LFront engine (so the green line).
Or did I get it wrong what engine is LFront? Here is how I understand the names of the engines:


A visual inspection of the propellors on the two faster turning engines shows no damage whatsoever in one case and minor wear in the other.

 

[Droning on and on...]

I wouldn't say they are split by handing (assuming you mean left Vs right). The right front engine and the left back engine are clearly spinning faster consistently. However 500rpm is probably not a huge difference.

This seems to indicate my damaged propellers are not in need of replacement right?

I don't have my drone with me at the moment, what Insights could you gain from getting the embossed letters of my propellers?

 

[Droning on and on...]

OK so the numbers are:
right front: 12 4726 F
All the other props: 13 4726 F
Does that tell you something?
These are the factory-installed props

 

[m80116]

I am sorry I can't help for the hover test. I have no idea if 500 rpm can be acceptable as things may scale to big numbers under load. Concerning launching from inside if you know what your doing it's OK but you need to have scanned the power up zone beforehand to really saty on the safe side.

 

[Deleted member 103366]

......ow grasp the Mini between thumb and index finger shortly behind the gimbal and under the front arms, with your hand coming from the front
- With your other hand do a CSC command for stopping the motors. A lanya........

I know the reponse is very late but I just came across this thread again.
Sorry but the CSC position is NOT the thing to do in that situation. Holding the throttle closed IS.
The CSC is telling the drone maximum reverse, roll and yaw, all of which will cause it to fight what is possible a tenuous grip.
Throttle closed keeps the props at minimum speed PROVIDING that the holding hand remains steady until the motors stop.

 

[Deleted member 103366]

Also a very good tip, although when I'm in 'panic mode' I'm not sure I will have the clarity of thought to do this.

Try a couple of practices, I find physically doing things like this help lodge them in my memory more securely than just reading about them.
I have HAD to do this (grab and twist) with an M2P because a dog was going bananas and trying to get the drone as I HAD to land it. The owners seemed unable to control the dog and I had drained the battery waiting for them to do so. I had to whip the drone behind my back to keep it away from the dog.

That speed chart is a bit unusual, what appears to be the norm is for the two rear props to be rotating faster than the fronts, if for no other reason than the rears carry more weight than the fronts.
Split handing wise (CW vs CCW), seems unusual.

 

[GerdS]

I know the reponse is very late but I just came across this thread again.
Sorry but the CSC position is NOT the thing to do in that situation. Holding the throttle closed IS.
The CSC is telling the drone maximum reverse, roll and yaw, all of which will cause it to fight what is possible a tenuous grip.
Throttle closed keeps the props at minimum speed PROVIDING that the holding hand remains steady until the motors stop.

You are partly right. Normally I am also just holding throttle down for stopping the motors, although this will take some seconds. But I also came into a situation where this didn't work at all. If the drone is in RTH mode or automatic landing because of low battery you can still overrule it a bit with the sticks and grab it, but pulling throttle down will not stop the motors. In that case you can only use CSC or turn the drone onto it's back.