I've ran in to the same problem running Ubuntu Server 20.04 (64-bit) on my Pi4. Its happened twice, both times after sudo reboot. (at first I thought it was because I downloaded then uninstalled vmlinux to build another machine, I didn't do this the second time around so know that isn't the case).
seems to me to be a problem with Ubuntu, I'll be installing ...
Probably. You really shouldn't use software PWM to control servos. The timing jitter will make them fidget causing them to overheat and wear our prematurely.
Use one of the many modules (software or hardware) which provide hardware timed PWM.
Try running v4l2-ctl -l and search for "white balance" or "color temperature" in the output. Usually, there's an automatic setting (a boolean) which lets the camera manage the white balance on its own, and a manual setting which lets you override that.
Those properties should be mapped to something like CV_CAP_PROP_HUE and ...
I found the problem. It was because of the power supply. I've made the tests with phone charger connected to RPI and the voltage on USB was 4,87. I've change the charger with another one and the voltage was increased to 5.1V and the RS232 adaptor is working now.
However, the fault was not only the voltage, because I've tried also with another RS232 adaptor(...
The firmware on the external usb hard drives needed to ''get acquainted'' with the usb connectors on the pi4.
I have three different brand external usb drives, call them red (K/L) blue (g/h) and silver (i/M).
Blue only worked with my USB2 connector on my laptop, red and silver with my laptop USB3 connectors.
Blue connected solo to an outside USB (2.0) ...
I experienced the same problem immediately after installing ufw:
$ sudo ufw status
ERROR: Couldn't determine iptables version
But after rebooting (without changing any other settings) it started working (as suggested here):
$ sudo ufw status
$ update-alternatives --display iptables | grep currently
link currently points to /usr/sbin/...
I can run sudo ip link set eth0 up as much as I want, and it still shows as down.
The output you posted contradicts this.
eth0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN mode DEFAULT group default qlen 1000
ip link sets this ^^ not this ^
> ip link ...
Clear the name cache in Windows.
Open an command line windows as an administrator and issue:
If that does not work try:
Make sure that all entries for the machine name AND IP address (IPv4 and IPv6) are removed from the known_hosts file on the Windows PC.
You can also try arp -d * if the first two do not work.
I have an 8.8" LCD with 480x1920 as well. I have looked at this post as well as another one that is similar.
I have the same issue as you had with it no being full screen. I added your buffer lines but it's still looks like this https://ibb.co/0GrkJpF
Here is my config. The timings line is commented out as I was playing with different settings. Were ...
For two displays, you could just define the optimal resolution/dpi for each device, and make a script which detects which display is connected, and set the desired resolution/dpi using xrandr with --mode, --dpi and --scale parameters.
For a general solution, check if xrandr | grep connected or sudo get-edid | parse-edid | grep DisplaySize report the correct ...
I recommend the snap package wifi-ap:-
After its installed its a simple matter of using the wifi-ap.config command to configure you access point and devices.
e.g. (Will give you a list of the current settings)
Once you've set your new options (wifi.ssid, wifi.security-passphrase and disabled=...
The closest I can think off is to use the [EDID=*] filter in config.txt BUT this only operates a boot time.
Full documentation is here but in simple terms:
Run tvservice -n from the command line for with monitors to ID the monitor
Add a section for each monitor in config.txt that sets the correct monitor mode:
seems I do not have the required reputation points to add a comment => adding it here.
between the slots that fit in this case there are about 2.5 cm.
the pi4b by itself seems to be around 1.5 cm high
I found a loverpi poe hat that seems rather compact but there are some reviews (few) that state they got their board burned with one user showing that the ...
It may be a power issue - do you have anything else plugged into the Pi?
The 3B+ was prone to 'iffy' WiFi with cheap adapters but using the 'official' one normally sorted it.
I would check the country code is set correctly as well on both your AP and Pi
It's possible you are using a very popular channel - fix the working channel on the AP
Sorry I'm unable to comment here so I've put some notes in this answer
hdmi_safe is fully documented here and is normally a good fall back but it is possible that you have put it into an area not specifically for the Pi 4 hence the 'no effect' you are seeing.
First thing is to check your monitor is in the HDMI port closest to the power port
Second thing is ...
The actual Pi PoE hat wants 48V, this switch can only deliver 24V. Connecting the two together won't necessarily blow up the hat, but it will not work.
It doesn't mean you won't be able to make custom PoE adapters which work with 24V. 150W is plenty of power for 8 Pi 4, even considering power losses.
I always use the package initramfs-tools which contains update-initramfs its a pretty easy to use script based initramfs-hook system. Though as making a single mistake will r
So when I've modified the /etc/initramfs entries I then just have to run..
sudo update-initramfs -u
I don't know. But on my Pi4B /dev/gpiochip0 appears to have 58 lines (this seemed to happen recently).
I've just checked the BCM2711 docs and it does indeed have 58 GPIO. That information had passed me by.
I can see this question, the performance of Rasperry Pi 4 on LUKS, is old, but it is more relevant now than ever.
It is quite common to use LUKS with AES because CPUs (like Intel's, AMD's, etc) include AES acceleration in the CPU. This makes AES fast because encryption and decryption is performed by hardware. On the other hand, Raspberry Pi CPU's do not ...
No, the ADC isn't broken. It can measure any value on unconnected channels, including a value which depends on the signal on neighboring connected channels.
If you want to create a slow "amplitude" signal from a faster signal, you need an envelope detector. That's how AM radios used to work.
The tutorial from the official Raspberry Pi web site is known to work but it uses traditional networking technology with additional helper program (hostapd) mixed up with modern systemd-networkd. For my opinion it is not very intuitive but error prone and does not support the powerful networking issues of systemd-networkd.
I suggest to try a clean systemd-...
did you enable IP forwarding ? (it is not mentioned in step-by-step)
dynamicaly (either) :
echo 1 > /proc/sys/net/ipv4/ip_forward
sysctl -w net.ipv4.ip_forward=1
or edit /etc/sysctl.conf (to have it persistant)
net.ipv4.ip_forward = 1
you can check using
disabling is done using 0
You can easily boot the Pi headless without a display - but
obviously to CLI not to a GUI.
If you want to boot to GUI without a display (e.g. to use VNC) you need to configure the Pi4 to use a default resolution. See https://raspberrypi.stackexchange.com/a/113873/8697
If you want to use a monitor it is preferable to configure with the monitor attached (so ...
Make sure that you are building your Flask app in a virtual environment where you have already installed latest psutil module. I am pretty sure you will not get any errors then. Also make sure none of your python scripts are named as psutil.py.
Please make a habit of using virtual environments to avoid these kind of issues if that is the case.
You created a configuration which is impossible to resolve:
application_one.service must start after graphical.target (G before A)
graphical.target requires multi-user.target (M before G)
multi-user.target wants to start application_one.service (A before M)
One way to break the loop would be swapping the order in which the units load. For instance you have ...
You can use these commands to clear the old iptables configuration (you can use it to rollback the changes if this doesn't work):
sudo iptables -F
sudo iptables -t nat -F
sudo iptables -X
I think use can use this commands to forward the internet:
sudo iptables -t nat -A POSTROUTING -o tun0 -j MASQUERADE
sudo iptables -A FORWARD -i eth0 -o tun0 -m state --...
I found the solution and it may help someone so I am going to post it.
I used Qt resources https://doc.qt.io/qt-5/resources.html and it will help you to integrate the images to the executable.
so under my test_v1 directory I created a file image.qrc (I used nano to create it)
after that in qtcreator I added to my project this file (right click on the project ...
While I like mDNS and the Macintosh implementation, I found that my Windows machine wasn't playing nice with it. I had to create an entry in my windows hosts file, and later on I used WSDD to replace the broken network discovery of netbios names.
hosts on Windows
This assumes that you have assigned a static IP address to your raspberry pi. I typically use ...
I use the "Geekworm Raspberry Pi 4 Aluminum Case" (Link) since a week with the 4GB model. This silent case cools all 5 chips passively (with itself as many other cases), not just 2, 3 or 4 chips as all other cases like this. Took some time to accidentally find it. Even if not all chips need cooling, better to be safe than sorry.
But I used Gelid's ...
I took another look at how I'm enabling the spi overlay, I was using dtoverlay-spi=on in /boot/config.txt to do so, which indeed gave me spi0.0 and spi0.1 when i check via the command dir /sys/bus/spi/devices.
I replaced this line with dtoverlay=spi0-cs, which still gives me the same devices, but suddenly the whole thing worked and I can succesfully read the ...
I would start by sending dummy data and checking that MOSI and CLK pins toggle. Perhaps you will discover that you forgot to activate the SPI overlay, or made a mistake calculating which pin is which.
This is safer than fiddling with MISO: you can't kill the Pi by measuring the wrong pin, but you can indeed blow it up if you apply voltages to the wrong pin.
Nothing is "hidden". The SOC is well documented although the Video Core is not public without an NDA.
The other items on the Pi may not have full details published because documentation takes a major effort and is expensive. There is no reason for the Foundation to fund this to meet its educational objectives.
I am sure that if you were prepared ...
Your cooling system is rather poor: I also have a 5V fan on a heat sink (the cheapest $1.5 variety) powered by 3.3V to reduce noise, and the CPU temperature is around 50°C while idle and rises up to 65°C under full load. Perhaps you should find a case with bigger vents: a totally enclosed case (with just connector openings) is 5-10°C hotter than a case with ...
This answer requires only that you know your local energy costs, your RPi's rate of power consumption, and simple math.
Your local energy costs
Electrical energy costs vary considerably by season and by location. Since you didn't tell us where you live, we'll use this source's estimate of world average price of 0.14 U.S. Dollar per kWh for households.
You make it too complicated if you need more space fine but this separate partitions idea is not needed. Once you have it setup on the Pi 4 there is tool in the menus called SD Card Imager I think it is called. Use this with the sd card as the source and the SSD as the destination, choosing the Use Random UUIDs option will ensure the card and SSD have ...
A power calculator below, a Pi on its own can only use 15W (3A x 5V) maximum or 17.5W with 3.5A power supply like I have. Put them numbers in this with your electric rate, I got $54.31 when using the 24 hours a day for 20W at 31 cents (the default rate) a kw/h. Since my power rate is under half of that I am doing good, I allowed extra for the spinning hard ...
If you're using RaspiOS 32 with the latest 5.10.11 kernel then you have /boot/overlays/spi0-1cs.dtbo and /boot/overlays/spi1-1cs.dtbo
Those free up the second CS pin. There's even an option to free up the MISO pin if you're doing send-only SPI transfers.
Info: Only use one CS pin for SPI0
If you are not using them for SPI you can use them for any of their alternative functions. So yes, just set them to INPUT mode or OUTPUT mode using the GPIO library of your choice.
However the current Linux SPI driver leaves them in OUTPUT mode as it drives the select lines itself. You might have to use a different SPI driver.
If you are using pigpio set ...
In general, any level shifter reduces the performance of a digital data line. For digital signals, it's often convenient to characterize a level shifter by the maximum frequency it can pass though.
Mechanical relays are very slow, working only at single-digit Hz frequencies. General-purpose optocouplers and MOSFET-based bidirectional level shifters are ...
Get a powered hub seems to be the "offical" advice I always see on their forum when talking of drives plugged into it. These things are so flaky with their USB if I plug in my keyboard I cannot boot, is my problem with the Pi 4 8GB I have with their implementation of USB. My power supply in the Canakit I got is rated for 3.5A.
You are on the right track, but if you are using the pi4 it has a different peripheral base address which for the pi 4 is 0xFE000000. You also seem to forget to map the clock register, check your gpioInitilise() inside you will see
gpioReg = initMapMem(fd, GPIO_BASE, GPIO_LEN);
systReg = initMapMem(fd, SYST_BASE, SYST_LEN);
bscsReg = initMapMem(fd, ...
Schedule a cron job which disables the screensaver / energy saving (xset s off -dpms) on Monday morning, and another job which re-enables the the screensaver / energy saving (or simply reboots the system) on Friday night.
Or permanently disable the screensaver/DPMS and manage the HDMI output using tvservice --off / tvservice --preferred
I copied a tutorial here:
Thanks to the built-in Wi-Fi, the newest version of the Raspberry Pi is more useful than ever for networking projects. We recently showed you how to use your Raspberry Pi as a wireless access point – a router, essentially – and now we have a project for you that builds on that. You can use your Raspberry Pi as a VPN access point, ...