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Just put these to the file /etc/modprobe.d/raspi-blacklist.conf
blacklist brcmfmac
blacklist brcmutil
This procedure is extremely important when using headless rpi as logger in the remote area. For the rpi, one needs to append a small text in the file /boot/cmdline.txt:
ip=169.254.10.10
Note that there is a space between the new string and existing strings. by doing this, one always gets same ip address at eth0:
pi@camellia:~ $ ifconfig
eth0 Link encap:Ethernet HWaddr b8:27:eb:83:c8:9d
inet addr:169.254.10.10 Bcast:169.254.255.255 Mask:255.255.0.0
inet6 addr: fe80::ba27:ebff:fe83:c89d/64 Scope:Link
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:70 errors:0 dropped:0 overruns:0 frame:0
TX packets:132 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:12403 (12.1 KiB) TX bytes:22786 (22.2 KiB)
For the laptop, one needs to do assign a static ip address as rpi has done. my laptop with Debian does not come up with file /boot/cmdline.txt and so I choose to change file /etc/network/interfaces
source /etc/network/interfaces.d/*
# The loopback network interface
auto lo
iface lo inet loopback
auto eth2
iface eth2 inet static
#your static IP
#address 192.168.1.118
address 169.254.10.5
#your gateway IP
netmask 255.255.0.0
#your network address "family"
broadcast 169.254.255.255
now the system always get ip based on the static prescription.
I wish to use 10m hdmi cable to work with pi camera using tindie flex cable to hdmi converter. it was found that 5m hdmi cable works perfectly fine while 10m would have strong noise. turns out, the noise could be reduced simply by shorten all the flex cable to 5cm. this suggests that high frequence data transimission does require proper cables.
apt-get install tmux mplayer tightvncserver rdesktop htop vim git ffmpeg vlc python-rpi.gpio ipython
# dpkg-reconfigure tzdata
(a). use gparted to shrink the empty space
(b). use
dd if=/dev/mmcblk0 of=/home/YOUR_USERNAME/Desktop/backup.img bs=1M count=2048 status=progress
sync
to save the file, the size is estimated to be 1M* 2048 for the case above.
when extracting the image to disk first
dd if=/home/YOUR_USERNAME/Desktop/backup.img of=/dev/sdc bs=1M status=progress
sync
and do not forget to use gparted to enlarge your space!
reference: https://www.raspberrypi.org/forums/viewtopic.php?f=26&t=5947&start=25 https://raspberrypi.stackexchange.com/questions/36456/how-to-shrink-an-image-file-after-allocating-full-space
put the below to /et/dhcpcd.conf, i think the server always need to determine their own IP in the first place
interface wlan0
static ip_address=192.168.4.1/24
becareful that debian squeeze seems not having this TO180620
add the following to /etc/dnsmasq.conf
interface=wlan0 # Use the require wireless interface - usually wlan0
dhcp-range=192.168.4.2,192.168.4.20,255.255.255.0,24h
try infinite if one does not want the ip to be expired then add the following to /etc/hostapd/hostapd.conf
interface=wlan0
driver=nl80211
ssid=hydrogeologger
hw_mode=g
channel=7
wmm_enabled=0
macaddr_acl=0
auth_algs=1
wpa=2
wpa_passphrase=123456123
wpa_key_mgmt=WPA-PSK
wpa_pairwise=TKIP
rsn_pairwise=CCMP
after that, uncomment in /etc/default/hostapd
DAEMON_CONF="/etc/hostapd/hostapd.conf"
finally, restart the services
sudo systemctl start hostapd
sudo systemctl start dnsmasq
the next is to forward the data to one port that is supposed to have internet eth0 here
/etc/sysctl.conf and uncomment this line:
net.ipv4.ip_forward=1
then run below two commands:
sudo iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
sudo sh -c "iptables-save > /etc/iptables.ipv4.nat"
save the rules on boot by Edit /etc/rc.local and add this just above "exit 0" to install these rules on boot.
iptables-restore < /etc/iptables.ipv4.nat
now reboot reference: https://www.raspberrypi.org/documentation/configuration/wireless/access-point.md
first find out the number of partitions in the file by:
$ /sbin/fdisk -l 2018-06_21_rpi3_stretch_hydrogeolog.img
Disk 2018-06_21_rpi3_stretch_hydrogeolog.img: 9.8 GiB, 10485760000 bytes, 20480000 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xc4b3f138
Device Boot Start End Sectors Size Id Type
2018-06_21_rpi3_stretch_hydrogeolog.img1 8192 137215 129024 63M c W95 FAT32 (LBA)
2018-06_21_rpi3_stretch_hydrogeolog.img2 **137216** 22067199 21929984 10.5G 83 Linux
so the start of the second partition is 137216*512=70254592
the way to mount it would be:
mount -o loop,offset=70254592 2018-06_21_rpi3_stretch_hydrogeolog.img /home/user/usb
Reference: https://unix.stackexchange.com/questions/82314/how-to-find-the-type-of-an-img-file-and-mount-it
run the command below:
$ echo -n password | iconv -t utf16le | openssl md4
(stdin)= 8846f7eaee8fb117ad06bdd830b7586c
so that the password in /etc/wpa_supplicant/wpa_supplicant.conf can be written as:
ctrl_interface=/var/run/wpa_supplicant
eapol_version=1
ap_scan=1
fast_reauth=1
network={
ssid="eduroam"
scan_ssid=1
key_mgmt=WPA-EAP
eap=PEAP
phase2="auth=PAP auth=MSCHAPV2"
identity="[email protected]"
password=hash:abcde
}
TO201214 it is found that after upgrading from wpa_supplicant version 2.4 to 2.6 in stretch, the above mentioned script is not working anymore, particularly that system does not reconglise PAP authentication when running the program:
systemctl status [email protected]
This will be resolved by removing auth=PAP in the line phase2:
ctrl_interface=/var/run/wpa_supplicant
eapol_version=1
ap_scan=1
fast_reauth=1
network={
ssid="eduroam"
scan_ssid=1
key_mgmt=WPA-EAP
eap=PEAP
phase2="auth=MSCHAPV2"
identity="[email protected]"
password="password"
}
it is also found that after the upgrade it is worthy to enable wlan0 by:
systemctl enable [email protected]
go to /etc/default/keyboard and change
When installing soft_uart it was asked to install linux headers. this could be done by running:
apt install raspberrypi-kernel-headers
The header file will be appeared in folder /usr/src
- check if pi is underpowered
pi@dp19_camera:~ $ vcgencmd get_throttled
throttled=0x0
so 0x0 means it is all good
always try to compare the directory name (ls /usr/src) with the acutal linux kernel (checked by running uname -a). if they are unmatched, just update the system up-to-date (apt update & apt upgrade)