DJI Mavic Air 2 conversion to ArduCopter

[maciek252 (Maciej Szreter)]

Photos explain (almost) everything. I think it’s very cost-effective, compare it to say GEPRC MOZ7 - for less money you get gimbal+decent video, and even a battery Many DJI copters are sold crashed/damaged.

The FC is Micoair H743 AIO V2.

There are two GPSes, maybe it’s an overkill. In the next build I’ll stay with a single one.

Some trouble with routing wires, so that it’s still foldable. But flies fine.

ELRS is 868 MHz, because of the strong video link ELRS 2.4 GHz does not work. In theory, it is possible to set the video link to 5.8 GHz, but it’s less range and it sometimes switches back to 2.4 GHz.

I had to solder the power connector directly to the battery’s pads, that’s the hard part because these pads are made of some kind of inox and soldering does not work easily. I’ve used a special liquid agent for soldering aluminium/inox, this must be reliable - test it by pulling the wires. On the copter’s ESC board, there are special round pads with +/-. After removing the top cover, I’ve added 4 holes and screws with spacers, holding two plywood pieces. The FC is on the lower floor, above it the ERLS rx. Bypassing the battery controller is necessary, because it switches off after a couple of seconds when under load. The motor wires are soldered directly to the FC motor pads.

Batteries can be charged in the normal way, no need to add a balancer connector.

I have not disabled the motor stuck protection in AM32, and one of the motors has some problems with starting, I need to fold the propeller in the direction of the rotation. But this is a minor issue.

Here I describe some problems with precise tuning, you can see some logs.

Pitch peaks in AUTO turns

I think you have a 3S Lipo, so you need to set these: BATT_ARM_VOLT,11.00 BATT_CRT_VOLT,10.50 BATT_LOW_VOLT,10.80 BATT_FS_CRT_ACT,1 BATT_FS_LOW_ACT,2 MOT_BAT_VOLT_MAX,12.60 MOT_BAT_VOLT_MIN,9.90 They are really mandatory, not optional. Don’t skip any. If you have a different battery type then please provide that detail. Since everything is not configured consistently, I guess you have about 14inch props, so set: INS_GYRO_FILTER,30 and this will be near enough. There are other related param…

[Allister (Allister Schreiber)]

Can you share more about the video and gimbal? How are you controlling the gimbal and handling the video feed?

[maciek252 (Maciej Szreter)]

The video feed and the gimbal control is left to the original DJI transmitter (so I use two Tx-es). I can switch between video and photo, start/stop recording, zoom and move the gimbal etc. Also the settings such as gimbal sensitivity, ISO, fps, shutter can be controlled.

What does not work is of course object tracking.

The DJI’s gps is covered by the FC stack, but sometimes it catches the fix and reports the distance, speed etc.

[rmackay9]

Hi @maciek252,

Txs very much for this. I’ve promoted this to a blog post because I’m sure many people will be interested in what you’ve done.

I think the camera gimbal is the biggest thing that DJI has over everyone else. We have just started a project to create open source camera gimbal software (announcement coming soon) but the hardware challenge will remain. I’m sure DJI has spent 10s of millions in R&D on their camera gimbals. My personal hope at least is that making the software free will allow more manufacturers to get involved and focus their efforts on the hardware instead of the software.

[maciek252 (Maciej Szreter)]

Fully agree. I’ve checked many options and there is simply nothing comparable. A gimbal+gopro - still no video link, and way heavier. Walksnail - hard to put it on a gimbal, and much worse video quality. Here you get excellent hardware, video link and recording, everything integrated into a very reliable airframe, and (three) batteries included!

EDIT: now I’m working on converting DJI Flip, which are surprisingly cheap even as new. I realised that this thing is so light that it might be reasonable to remove the arms with motors and propellers, and use the body simply as a camera+gimbal+video link.

[geofrancis ([𝙂𝙚𝙤])]

very cool. I done a couple of phantom conversions years ago.

[maciek252 (Maciej Szreter)]

Flip completed its maiden flight, and this even included the QuikTune (successful).

Easier to build, cleaner, less cables. 2S batteries, no need to hack them. MicoAir H743 v2 AIO happy with 2S. The extra weight penalty bigger as the whole thing is much lighter, but as I’ve read on the internet, it takes 50g easily and the mod is less than that.

A problem: the battery won’t charge over USB connected to the drone (the FC takes some power, maybe a stronger USB charger would do). The solution: external battery charger.