noahwilliamsson / dji-phantom-vision Goto Github PK

Fantastic work so far!

I found something a few weeks ago, but don't have the experience to really vet it out. ser2net allows two connections to a serial port - one 'raw' data connection (2001, as you know), and one telnet port. The telnet port is configured as 3011.

When you telnet to 3011, you get some interesting output that seems quite similar to the message packets, although after looking through your C library, seems like it's the 0xFF error state. I'm curious if there is some way of obtaining useful data from here, though.. perhaps sending some sort of ack packet? (Dunno if the raw stream connection does that - we'd have to sniff the traffic from right before the Vision app connects)

My essential goal here is to be able to write some sort of program/library that can obtain data real-time from the Phantom with a second device (initially a computer), while allowing the phone/tablet-based Vision app to operate normally and uninterrupted.

Thoughts?

Here's the output from my brief test:

λ telnet 192.168.1.2 3011
Trying 192.168.1.2...
Connected to 192.168.1.2.
Escape character is '^]'.
this is ser2net TCP port 3011 device /dev/ttyS0
second line third line
55BB07043897FF 
55BB07043883FF 
55BB07043887FF 
55BB07043897FF 
?
 B?NBBB?NB?
           B?NB?HB?B?NBB?NB?JB?B?JBB?NB?NB?B?JB?

Hi,

I thought this might be relevant as you're struggling with the checksums,

I've just started trying to decompile the android DJI Vision app, and it has a precompiled library that it uses for the ground functions called libGroundStation.so

It exports the following checksum-related functions:
jVerifyChecksumCrc16(_JNIEnv _,_jobject *,_jbyteArray *)
DjiVerifyChecksumCrc16
jCalcChecksumCrc16(_JNIEnv *,_jobject *,_jbyteArray *,int)
DjiCalcChecksumCrc16
jVerifyChecksumCrc8(_JNIEnv *,_jobject *,_jbyteArray *)
DjiVerifyChecksumCrc8
jCalcChecksumCrc8(_JNIEnv *,_jobject *,_jbyteArray *)
DjiCalcChecksumCrc8
jcheckCRCForData(_JNIEnv *,_jobject *,_jbyteArray *)
checkCRCForData(uchar *,int)
jgetCRCFromData(_JNIEnv *,_jobject *,_jbyteArray *)
getCRCFromData(uchar *,uchar *,int)
jdecodeData(_JNIEnv *,_jobject *,_jbyteArray *)
decodeData(uchar *,int)
jencodeData(_JNIEnv *,_jobject *,_jbyteArray *)
encodeData(uchar ,int)
jniRegisterNativeMethods(JNIEnv *,char const,JNINativeMethod const,int)
__udivsi3
tea_encrypt
tea_decrpyt <- their mistake, not mine
key_tea
Get_CRC16_Check_Sum
wCRC_Table
Verify_CRC16_Check_Sum
CRC_INIT
Append_CRC16_Check_Sum
gs_cal_crc
gs_get_crc
DjiCalcChecksumXor8
DjiCalcChecksumXor32
DjiCrc8Table
DjiAppendChecksumCrc8
DjiCrc16Table
DjiAppendChecksumCrc16

I thought that might be helpful!