Phantom – JToB's projects

After my Y6-Copter with APM, I also want to see telemetry data of the Phantom 1, which isn’t capable on its own to transmit any data.

The original PPM receiver (Single antenna) got swapped by a FrSky XRS, which is amazingly small and has PPM, S.Bus and S.Port.

The translation between Naza-GPS and S.Port is done by an arduino nano which is connected to FrSky-S.Bus on Pin9 and to GPS Tx on Rx (also power from the receiver cable).
I used the software by Alezz in this thread but had to make some changes to get it running. My changed version is online at GitHub.

Here are some Pictures of the harness with the arduino and the Installation in the Phantom 1.

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I didn’t want to cut the GPS connector, so I just pushed a jumper wire in the connector.
That was initially just for testing but made such a solid connection that this will stay in there.

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The GPS Format in Degrees+Minutes formatted as DDMM.MMMM.
So 1234.5678 means 12°34.567′

I still have some trouble with the GPS coordinates, sometimes just the Longitude will be transmitted and Latitude is just 000 but this will be updated as soon as I get further.
Also I’m a little confused about the “Alt” “Galt” and the “Alt” on the GPS screen. They all differ, but I will observe that during flight and remove the ones I won’t need from the arduino code.

I recently bought a cheap broken DJI Phantom 1 and would like to show you the process of analyzing and repairing the drone.

There were multiple problems, I will explain them one by one.

1. Phantom drops down when tilting

Problem

Here you can see that the phantom is hovering quite nice, but in the forward flight it suddenly falls down, all LEDs went off.

Cause

The Phantom has an internal USB cable which is connected to the microUSB port of the LED-module. This cable usually is hold in place by a cable tie and is accessible by the battery door.
In this phantom, someone removed that cable tie and the cable was flying around loosely, causing a short on the solder points of the battery connector or the power line for the speed controllers.

Solution

Fixed the cable with a cable tie. – Easy one…

2. Copter falls again midair

Problem

The Copter falls down while hovering, all LEDs stays on and starts beeping.

Cause

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The X3 connector from the PMU-board to the Naza is the power source for the flight controller. The red wire is the +5V line which has a loose connection on the board, although covered in the white protective glue.

Solution

I simply replaced the cable with a new one…

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Easy to fix, hard to find.

3. Copter wobbels in ATTI mode – (really easy one)

Problem

When flying in ATTI-mode (Stabilized, without GPS), the copter starts to shake and wobble.

Cause

The previous owner changed the default board with the PMU-One for a zenmuse gimbal. The Naza (which contains the gyro sensors) is usually glued to the board with foam pads.
In this case, it was glued with superglue, wich won’t adhere to the coated PCB. So the Naza became loose and was just hold by the cables. I was impressed how stable it stays with this in GPS mode!

Solution

Fixed the Naza with foam tape.

4. Phantom randomly switches from GPS to ATTI mode

Problem

During a GPS flight, the LED randomly turns yellow for a few seconds and the copter starts drifting which means that it switched to ATTI mode.

Cause

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In the upper shell of the phantom is the GPS module which contains the antenna. To reduce interferences from the regulators, it is shielded with a rubber coated copper foil.
This foil was lacerated and the the copper foil wasn’t insulated on some parts. These touched the GPS module and randomly caused it to fail.

Solution

Just added some duct tape as insulation between the module and the copper foil.

Now, it seems to fly very stable and reliable. There are already further modifications queued…