Category: Raspberry Pi Page 1 of 3

Steps:

For some reason, if you get a message like following:

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

@WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!

Someone could be eavesdropping on you right now (man-in-the-middle attack)!

It is also possible that a host key has just been changed.

The fingerprint for the ECDSA key sent by the remote host is

SHA256:iudbciuwbciubwi/TFutvavUVUY/76THBSJHB7Shdb.

Please contact your system administrator.

Add correct host key in /Users/user/.ssh/known_hosts to get rid of this message.

Offending ECDSA key in /Users/user/.ssh/known_hosts:2

ECDSA host key for 192.168.0.XXX has changed and you have requested strict checking.

Host key verification failed.

then do this on your terminal:

ssh-keygen -R 192.168.0.XXX

Credits:

https://www.digitalocean.com/community/questions/warning-remote-host-identification-has-changed

Steps:

1. Run the following:

sudo apt-get install realvnc-vnc-server

2. Raspberry Pi OS has the SSH server disabled by default. Enter

sudo raspi-config

3. Select Interfacing Options

– Navigate to and select SSH

– Choose Yes

– Select Ok

– Choose Finish

4. Learn your Pi’s IP address from your Pi’s terminal:

hostname -I

or from another device connected to the same network:

ping raspberrypi.local

Credits:

https://www.raspberrypi.org/documentation/computers/remote-access.html

I spent a lot of time and tried connecting two bluetooth devices to get audio from Raspberry Pi 3B+, but it looks like there is no way to do this with Bluetooth 4.2. You can connect multiple bluetooth speakers to Raspberry Pi, but only one of them will sound. The other one is just a connected ‘card’ when you do:

pacmd list-cards

but it does not appear in ‘slave’ list when you do:

pacmd list-slaves

Following will give audio output from two sources, but with a relatively significant delay: (In my case, HDMI and Bluetooth)

pacmd list-sinks

pacmd load-module module-combine-sink sink_name=MyCombine

pacmd update-sink-proplist MyCombine sink_properties=MyCombine device.description=MyCombine

pacmd set-default-sink MyCombine

Just do:

alsamixer

Credits:

https://www.bareconductive.com/blogs/resources/how-to-change-the-volume-on-the-pi-cap

If you want play videos on a headless Raspberry Pi OS, you cannot pause or control the video. Following will let you control the vlc player:

vlc -I ncurses <filename>

Credits:
https://www.raspberrypi.org/forums/viewtopic.php?t=257395
https://wiki.videolan.org/Documentation:Modules/ncurses/