Long story short but…

You have a Pi3 (B+). You do an os upgrade. Your wifi become unstable and/or stops working…

Culprit is broken update. You need to rollback the upgrade for the network. This is how to do it:

Run:

wget https://archive.raspberrypi.org/debian/pool/main/f/firmware-nonfree/firmware-brcm80211_20161130-3+rpt3_all.deb

sudo dpkg -i firmware-brcm80211_20161130-3+rpt3_all.deb

sudo reboot

For more information – see this link:

https://www.raspberrypi.org/forums/viewtopic.php?f=28&t=249750&sid=0e48494349b8a53c664aaa761cdacbff

A cluster is used to work on distributed computing tasks. So things that need a lot of number crunching. The idea is to run many processes at the same time to make the whole run quicker. Note that often the single processes will take longer because they need to be assigned and marshaled etc (overhead) but running many at the same time makes it worth it.

A GUI , which is what your desktop is, is not suitable for this because there are many different processes that run at random times. The best way to speed up desktop is:

• Faster disk
• Faster/more memory
• 64 bit OS to tack advantage of memory
• Faster processor
• More cores on processor
• More caching memory
• Etc

(the above list is not in any order)

So the short answer is “no”😊

It should be easy – take a screenshot. Well – turns out it is but it’s not exactly the latest and greatest in tools…

“Scrot” is a screen capture tool installed by default on pi os. Nice – but – it is just that – it captures the whole screen. Just press “Prt Scrn” and click – a nice picture saved in your Pictures directory. Fine, all well and good, but what if you only want the active window?

A quick google found the “Gnome Snapshot tool” (gnome-snapshot). It’s simple and effective. I allows you to capture:

• fullscreen
• active window
• area,

How to install?

sudo apt install gnome-screenshot

Run it from the menu, place it on your desktop or change the keybindings for prt scrn.

Hint – to change keybindings – here’s a useful link to Tom’s Hardware:

https://www.tomshardware.com/news/raspberry-pi-custom-keyboard-shortcuts,40215.html

Nice 🙂

The latest version of chromium on raspberry pi OS does not work for Netflix. This is because wildvine (DRM software) is broken.

There are a lot of tutorials and advice on how to get this fixed. The two most popular are to use Kodi and to get chromium media edition.

Using media players (like Kodi) seems a bit of overkill when all you want to do is watch via the browser. It’s also quite a messy way that never worked for me.

By far the easiest way I have found (and also works for Disney+ and probably anything else that uses wildvine) although Spotify is a little unpredictable is to install “pi-apps” and use that to install what you need.

It can be found here:

https://github.com/Botspot/pi-apps

This little wonder also makes visual code easier an a number of other apps to install.

One thing to remember…

If you install chromium media edition, kill all other chromium processes before you start the media edition.

If you don’t then it won’t work.

Hint – you can use htop, put it into tree mode and send sighup to the root chromium process. htop is also very useful to monitor whats going on in your system. If it’s not already installed the sudo apt install htop.

An early birthday present to my self – 4Gb Raspberry Pi 4B. With a case and a fan and a 3A power supply. Also – a vendor supplied 16Gb SD card preinstalled with latest raspbian. and lastly – an external USB 3.0 SSD housing.

What could possibly go wrong?

Reading the documents – it should be easy to boot from the latest version of RaspberryOS (aka Raspbian). Just download the image, un-tar, burn it to the disk, plug the disk in and boot.

Well – erm – nope.

First was the fun and games with the supplied SD card. You would think the vendor would supply an adequate, fit for purpose, unit? Nope. They must have found the nastiest, cheapest, slowest PoS they could. Booting it took for ever. Once booted – I ran the diagnostics because there is no way this can be slower than a 3b right?

Diagnostics are giving almost 50 IOPS! Wow – that fast. NOT. The limit is set at something like 400. Doubtless to say the card was not fit for purpose. But thats ok right – I plan to burn to SSD and boot from that anyways. Using the pi to do this was not the most pleasurable process. It took literally hours.

In the end (and 3 nights later) – I quit with it. I got an old card that I knew worked, flashed the latest image, booted and bang – it was there. Amazing. Even just running from the card was fast. 4Gb really makes a big difference. Chrome would run without killing the entire OS.

Next step – start again with the SSD. Burned the image – booted – nothing.

Waited – nothing.

Tried again – same thing.

Strange.

One thing I found was that it kinda worked if it went through USB 2 rather than 3. Ok – this pointed me to something else…

https://jamesachambers.com/new-raspberry-pi-4-bootloader-usb-network-boot-guide/

The need to update the firmware on the USB/SATA. Did that. Booted – almost same thing. Note – almost – when doing this sort of stuff – keep an extra eye out for things that are slightly different – it’s important.

I would love to provide the link but I’ve managed to loose that one.

Googled again – Now we find out that there is something called UAS. And it’s important. Because on some cheap units – it’s not implemented entirely cleanly. This resulted in finding out way more about the boot process than I ever really wanted to know and also editing a file in the boot directory to add an exclusion for that protocol. Downside is that it would slow my disc down a bit but it would still be way faster than SD.

So I did that.

And guess what?

It worked!

Finally, after a long time and much trying but not giving up. Nice new PiOS on a 128Gb SSD.

Well impressed.

Lessons gained:

• Don’t give up
• Look at the small differences – they may give you a clue.
• Try different ports
• Google and read what you google. Don’t skip the detail.

Update…

These are useful resource links:

Jeef Geerling – pi 4 booting from SSD

https://www.jeffgeerling.com/blog/2020/im-booting-my-raspberry-pi-4-usb-ssd

PI4 USB boot Ubuntu:

https://www.raspberrypi.org/forums/viewtopic.php?f=131&t=278791

Update firmware for JMS578:

https://wiki.odroid.com/odroid-xu4/software/jms578_fw_update

How to improve speeds for PI4 USB

https://www.raspberrypi.org/forums/viewtopic.php?t=245931

I’m going to write this here for later versions of me to refer back to.

Using a WeMos mini D clone – how to get it working with micropython.

Flashing the thing is fairly straight forward using esptool – just remember that the tool is case sensitive – so – this means that you need to write COM4 rather than com4.

What else? THONNY is kinda useful as a simple ide.

My soldering is shitty.

Check the address of the i2c device. i2c.scan() returns a decimal – you need to convert it to hex. In my case I was getting errors like this:

Traceback (most recent call last):
File “”, line 2, in
File “BME280.py”, line 153, in init
File “BME280.py”, line 159, in _load_calibration
File “BME280.py”, line 119, in readU16LE
File “BME280.py”, line 102, in readU16
OSError: [Errno 19] ENODEV

Kinda strange – indicates no device being detected. At first I thought it wasn’t soldered correctly. Then maybe pins were wrong but no….

The default address in the BME280.py file was 0x76. I needed 0x77.So I changed it in the library then finally found out that it doesn’t update the lib on the device. I will remember for next time.

What is good though is that because I could get a stack trace for the error – I could go into the lib and call the I2C stuff at low level – that was how I found out about the device was actually working and wired correctly, it just needed the correct address.

So – part 1 of many just works. Happy:)

So – you have a few batches of wine (or indeed, whatever) on the go. You wrote everything down in your book and now you go to your notebook and find out that one of the kids has used it for school. Disaster has struck…

No notes.

It’s not exactly the end of the world but it’s inconvenient at best.

Here’s an online idea for you that may help save some frustration and a few batches of wine.

The internet has many useful tools and services that you can take advantage of for free. Of these – I would like to introduce you to:

• Trello
• IFTTT
• OneNote (or EverNote)*

OneNote is a Microsoft program and may not be free – sort of depends on your license. EverNote is free for all, although you may be limited in the amount of records you store (but for our purposes – it will do fine).

Trello uses a “board” to store a number of Lists. Each list is made up of cards. A card can have various information with it (due date, photos, text etc).

If we use one board called say “Wine” and then make a list per batch of wine. We call a list after a batch of wine e.g. “strawberry”. We create a card for “Starting” and in the card we put a due date of the day started. I also put in a link to the recipe and some other stuff in there.

Then, when you rack the wine, you create another card called “rack” with a due date the day you rack. Continue with adding a card for each time you do something. A nice way to keep records. But, wait, there is more…

The “Due Date” field can be used to plan. Create a card for say “Bottling” and put a due date in the future – and you get the basis of a planning system as well. Nice. When you’ve done the job on the card – mark it as done (and make sure the date is the date you did it) – so you can have a good indicator of where you are.

How does that look in practice? A bit like this:

And this is what a card looks like:

Give Trello a go – it’s kinda cool. You can also share your boards with other people. This lets people work together for say maybe if you have a shared room or such and need to see where certain things are. (I don’t want to use the term “project management” but you get the idea).

This is all well and good but it’s not a real notebook – more of a scheduling tool. This is where we bring IFTTT (If This Then That) into play.

We can make it so that when you enter a new card – it adds to your online notebook. By connecting Trello to IFTTT and then into OneNote or EverNote then you can take your note taking to a new level.

First, make sure you have a OneNote available online. EverNote is always available online so it may be a little easier to deal with.

Then go to IFTTT and create an account. There are some good resources there that explain the next step – linking IFTTT to Trello and also to your OneNote/EverNote. When those two services are added – you need a recipe like the following to do the lifting of creating notes from cards:

When this recipe is run it will add a new page to your notebook. For me – this is OneNote and looks something like this:

This is just the start of where this can go. Using services like IFTTT, we can link numerous things together to get some useful and handy solutions in place.

This one may make you wonder but don’t…

What do two pieces of PVC pipe and one end cap have in common with the BBQ? Nope, I didn’t know either until I read about this wonderful contraption/concoction. Read the following link:

Cowgirls Country Life

Today after supposed to be walking and being health with the Scouts and having bad weather cancel play, I dropped by the hardware store. I wanted some fire bricks for the Weber. Sadly they didn’t have any but they did have the above mentioned PVC pipe. So I got some with the fatty piston in mind.

After a few minutes with some glue and the Dremel, I gone made me a new kitchen tool…

Hint if you make one of these, PVC pipe dust gets every where.

So, what am I going to make with this?

Right now, I don’t know but I’m sure I can find something good tomorrow and report back:mrgreen:

I’ve just seen this link:

Make your own drum kit

So I am going to:)

On top of the Raspberry Pi – I’ve ordered an Arduino starter kit already and with the winter coming in and kids wanting to play – it’s a good time to start and this I think is a good first big goal after doing all the little learning projects that get you this far.

 

After much delay, I finally got the Raspberry PI up and running.

It’s now running Wheezy on an 8Gb card clocked to a modest 800MHz. It’s slow running X but this I knew.

What really did surprise me was the lack of effort needed to connect it to the wifi. Really was a case of bang in a USB dongle, use the wifi-config tool to set up the SSID info and boom – it’s connected. Well impressed. It’s also stable which is even more impressive.

One thing though to remember – the PI don’t do good on an under powered power supply – so using that old black berry charger rated at 500mA just won’t cut the mustard. Samsung’s USB Travel charger is rated at a very nice 1A. LIKE.

What am I going to do with the PI?

Well – for now – just brush up on Linux and Python etc. I will try turning it into an FM Transmitter. Of course this is probably illegal but the range is only 100m +/- and use a frequency that is not (much) used;) And it won’t be 24/7.

After that?

There are some cool things to do with simple I2C bus stuff and then maybe look at interfacing to Arduino and generally messing around. All good fun.