I was having a strange error with my DJI Air3s drone, it was reporting that I wasn’t connected. Then after I try to connect typing my email (and confirming the agree checkbox) it was reporting “Check network” error.

And it no matter which WiFi network or hotspot I use, it always was reporting this error. Strangely if I click in the Update firmware message the remote controller was able to download and update the firmware without issue.

Some after testing I discovered that doing a Factory Reset of the RC2 was enough to fix the issue.

Settings -> System -> Factory Reset

Really cool instructions and 3D parts provided:

You started looking the volumes:

user@ubuntu:~$ docker volume ls
DRIVER VOLUME NAME
local docker-lab_postgres_data
local b1aa150eb6ddb45084ff2b4554394c100c59a41c...
local client_postgress_db
local client_container_data

Then you try to remove:

user@ubuntu:~$ docker volume rm client_postgress_db
Error response from daemon: remove client_postgress_db: volume is in use - [553052b480de56abf196c34182780f1a86d35cdab989c15475e470ba7a67edee]

The solution is listing all containers, filtering by volume:

user@ubuntu:~$ docker ps -a --filter volume=client_postgress_db
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
553052b480de telix:1.0 "start-system.sh" 7 hours ago Exited (137) 6 hours ago client-app-1

Then remove the container:

user@ubuntu:~$ docker rm 553052b480de
553052b480de

And finally remove the volume:

user@ubuntu:~$ docker volume rm client_postgress_db
client_postgress_db
user@ubuntu:~$

This video tutorial is very good to show how to interact with an analog pressure sensor:

This project is really cool and it is in my TODO list!

https://github.com/0x23/MicroManipulatorStepper

I found this suggested circuit:

At this thread: https://electronics.stackexchange.com/questions/166301/using-a-microcontroller-adc-to-measure-a-4-20ma-sensor

There are many commercial solutions to use 4-20mA with microcontrollers, i.e.:
https://www.mikroe.com/4-20ma-r-click

Or you can use INA260 to measure current directly like this guy did (note: INA260 is not ideal for low current):
https://www.youtube.com/watch?v=GzxyzwyHRN0

Just use these two commands:

$ arm-none-eabi-objdump -d u-boot | grep "<phy_config>"
80837ff4 <phy_config>:
8083938c:	f7fe fe32 	bl	80837ff4 <phy_config>
$ arm-none-eabi-addr2line -e u-boot -f 0x8083938c
cpsw_phy_init
u-boot/drivers/net/ti/cpsw.c:856

These are some implementations I found in the Internet:

Javascript:

https://github.com/ibid-11962/Windows-95-3D-Maze-Screensaver

Rust:

https://github.com/clrnd/win95-maze-rs

(This is not a recreation) This guy added navigation control to the original 3D Maze screenshot:

https://github.com/x86matthew/Playable3DMaze

I found this nice video tutorial at Youtube video:

https://www.youtube.com/watch?v=WjSRCX4OrZU

Then I downloaded the example from: https://bitbucket.org/c-code/snakegame/src/master/opengl_cube.c

but when I tried to compile I got this error:

$ gcc opengl_cube.c -o cube -lgl -lglu
/usr/bin/ld: cannot find -lgl: No such file or directory
/usr/bin/ld: cannot find -lglu: No such file or directory
collect2: error: ld returned 1 exit status

So, the solution was installing these packages:

$ sudo apt install build-essential libgl1-mesa-dev libglu1-mesa-dev freeglut3-dev

Then I noticed my other mistake, it should be -lGL and -lGLU, also -lglu was needed:

$ gcc opengl_cube.c -o cube -lGL -lGLU -lglut

I bought a really low cost WiFi after watching the LowLevel channel video about hacking a similar device. But in this case the device was using a Qualcomm chip, mine came with a MT7628KN inside (board’s silkscreen: HX7628_L2_20210109).

Searching in the Internet I found many datasheets and programming guides for this chip and also there is a qemu support to it:
https://github.com/newluhux/qemu-mt7628