News from the Pi Curious - the Good, Bad and the Ugly.

The good, two Pi Foundation courses which I have registered for will teach me how to teach Pi The bad - I've been away for comp.sys.raspberry-pi too long. 128GB TF card unsuitable for Pi OS ops. The ugly - I ruined a Pi Zero and Pi 2b, each the same day I decided to powerup my new 3b. Warning: contains Product Reviews.

I'll be starting two Pi courses Feb. 20th from FutureLearn -

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Teaching Programming in Primary Schools - Raspberry Pi Foundation
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Teaching Physical Computing with Raspberry Pi and Python - Raspberry Pi Foundation
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so I've been brushing up on my Pi skills

To prepare for the courses, I ordered a Pi 3+b, a Pi Zero and support accessories for the Zero.

I've been mostly working in Python 3 and jumpstarted my extensive CS language background with the Monk book to adapt my coding skills to Python, with an eye on Perl and SQL under a variety of Linux distros. I got hooked into coding web scrapers after cutting my teeth with Fibbonacki, prime factoring and cryptography. Then I coded a suite of scrabble style helpers, lingering momentarily in assembling really big lists of English language words. Then I coded a sort which arranges that list into highest scrabble value order, which I intend to publish as coding curriculum here on c.s.r-pi. I then stagnated applying that to win prizes like concert tickets and such on-line.

When I ordered the support equipment for the Pi Zero, I should have included some heat sinks, but I'll tell you about the Ugly in a few paragraphs. Some of the tools I though I would need were OTB male to USB A female adapter, WiFi,or Ethernet USB dongle, various TF cards and a wireless keyboard/mouse combo.

I ordered the Pi 3 with a 8GB NOOBS TransFlash card in an adapter. And from AdaFruit I ordered the Pi Zero. I ordered two different hubs and planned to compare their suitability along with three USB hubs I already have, powered, unpowered but powerable and passive. First I'll describe the one I felt was best for my application - preparing a mass of Pi Zeros to operate embeded as well as preping another mass of pi Zeros as a single stacked supercomputer, I dubbed the winner 'umbilical:'

Raspberry Pi Zero perfect umbilical mate -

4 in1 Multi Function Black Micro USB Power Charging OTG Hub Combo Adapter Cable

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This OTG hub powers the Pi Zero through its OTG USB port and adds much needed functionality! The Raspberry Pi Zero is perfect as a lightweight, low cost, low power, embeded project brain, without the extra expense and weight of Ethernet and USB ports. But research programming, communication, project development and churning out production units can be a port pain on the PI Zero. This is the perfect temporary umbilical hub combo cable which preserves the final product low cost and weight with the ability to momentarily include USB adapter web access which is required to update and upgrade the Pi, command the initial setup with a USB mouse and keyboard as well as transfer programs and files from full size SD/HD as well as TF/micoSD mount. I use a USB WiFi dongle as well as a BlueTooth Keyboard/Mouse and the ablity to twist the cables apart helps prevent interference which would not be possible with a hard case USB hub. The OTB pass through power can safely power the Pi Zero through the USB port when attention to adequate power for all hub attaced devices is provided for, so use 2 Amp with this hub for testing/development and the regular 1 Amp when the umbilicle isn't in use to power the Pi Zero. The greatest feature is the OTB male plug which mates directly to both the power and USB ports of the Pi, so you don't need to find a USBa to OTB adapter or additional cable. CAUTION: I fried my Pi, not from this hub, but because I had an automatic sensing HDMI port switch attached attached to the PI without any other HDMI devices powering the switch when I finished and SHUTDOWN -power commanded the Pi. The auto-sensing HDMI continued to draw 'keep awake' power through the PI and tunneled/fried a capacitor in the Pi's power circuit. So unplug powered devices from the Pi Zero before sending that command while this hub is powering the Pi Zero through the USB port. That may not have happened if I was powering the Pi separately through it's dedicated OTB USB power socket.

I can see that I'll be using it on the test bench for Android projects. I use this OTB hub to crank out Raspberry Pi Zero embedded projects. To fully realize the full potential of this Pi/hub combo, one will still need a display, keyboard, Internet access and USB WiFi dongle/Ethernet adapter. USB keyboards are plentiful and inexpensive. Once I get The Pi p and running, I leave a WiFi dongle attached with a small USB/otb adaptor and SSH in from my laptop, allowing the keyboard/mouse and display to be remote. I reccomend this hub paired a Raspberry Pi Zero as the lowest cost alternative to facilitate the Pi curious and STEM students exploring robotics and or computer science.

The rest of the hub evaluations each required adapters - Ultra Small Device USB Male to USB 2.0 A Adapter Plug OTG Data Converter

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I pushed on the metal sheath too hard and ended up with what I really wanted to begin with - a simple tongue which slipped into a USB A male plug and mated with OTG on the RPi Zero. The sheath was easily restored, but when miniature aircraft is the Zero target the stripped version will utilize fine.

When the Pi 3 arrived I was waiting for my original Pi2 Python chron scripts to complete, with the intention of vampiring the clear case and heatsinks for the new Pi3b+. The Pi Zero arrived before all of the support accessories. But I jumped the gun and powered it up with the NOOBS card which came with the Pi# - I should have waited. The bluetooth wireless keyboard/mouse Ultra-thin 2.4G Optical Wireless Keyboard and Mouse Combo Kit with USB Receiver

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and the Multifuntional USB 2.0 High Speed 3 Port Hub With Wireless WiFi Router Function

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came and I tried them out on the laptop running Puppy Linux which I will use to SSH into the headless Pis. The keyboard I like but the response of the mouse is slow, causing operator oversteer and correction. I plan to get one more for the classroom to carry about the workgroups - I like the translucent spillproof neoprene cover. It worked straight away on anything I plugged it into. Not so with the wireless in the hub. It came with a miniCDrom with drivers, but I'm unfamiliar with tar.gz installation. The hub function was fine but the WiFi remained unconfigured. Puppy and Windows needed setup, but when I swapped out my existing WiFi dongle originally shipped in the Pi2 Vilros kit, my router saw it and I configured the router to give it an infinite lease on an assigned IP address. Then it worked in Puppy and Windows.

A few MicroSD Real 32GB Micro SD TF 32 GB Memory Card + SD Card Adapter s

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came with a dheap 128GB TF card. The 32GB cards work fine for Pi and I plan to buy more for other, camera, devices. They load Pi Ops just fine. The 128GB failed on loading it with my music library. It just vanished. wouldn't show up and couldn't be mounted - $8 brick.

I had the Pi Zero sucking on my mobile phone power for a few days while trying various ways to SSH into it while I waited for the final order 3 Port 1080P HDMI Splitter Cable Multi Switch Switcher For HDTV XBOX PS3 Lot BE

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to which I added three Mini HDMI Adapters to the order (same URL) I should have utilized the two HDMI inputs on my TV and used the remote to switch ports. But instead I had to try out the switch as I was finally enabled to see what the RPi Zero was displaying.

Now with two WiFi connected, the vampired Vilaros kit dongle and the Hub connected, the wireless keyboard and the HDMI switch, the Zero let me log in, set up SSH, run sudo update and upgrade. But when time to restart came it just looped and restarted each time it tried to establish a WiFi. I pulled the WiFi hub and just ran the Zero powered through the USB port using the umbilical hub, which worked fine at 1 Amp.

I was able to mimic the Pi2 after SSH and SSHFS mimic the Pi2 on the Zero. All my Python and Shell work copied over easily and worked just as well at half the power of the Pi2.

It was when sent the Zero command 'shutdown -P' that I had trouble, for I had also shut down the Pi2 first while both had been sending HDMI through the HDMI automatic switch - bad move. The switch draws power to decide which port is sending, and it continued to brown-down the Zero while I examined the shutdown on the TV, just one final green blink. It must have tunneled/fried a capacitor in the Zero power circuit, for it never responded to powerup again, not even an LED pilot lamp flicker. = $5 brick.

So I threw up my hands in disrepair, er despair and moved on to focus on first light of the new Pi3b+ The idea was to take the existing 2b out and swap in the 3 using everything that was on the 2. I went too far. I ruined the memory cap on the processor - the heatsink adhesive was too strong and wouldn't release from the processor, even with solvent and careful wiping and cutting with a sharpened street cleaner brush. Well, I should have waited for a new heat-sink and just run the Pi3 without one for a while. Cracked and crinkled I scraped off the memory from the heatsink and applied it to the new Pi3. I a matter of a few hours I've manged to go from three working Pi's to just one. That's ugly. Having swapped out the board I tried it, no good - it won't boot with the Pi2 TransFlash card, but the NOOBS card shipped with it, and that I had installed in the Zero to get it started and had transferred my files to, booted the Pi3 just fine. I'm happy that a large file load and search is significantly faster than the Pi Zero and Pi2b.

Live and learn, oh well.

I had ordered several 32GB TF cards, they all are fine. The 128GB TF card was purchased to enable an enormous wiki to fit, fried and died before it ever made it to loading Jessie. However, after reading c.s.r-pi lately, I've determined that a 4GB TF card would hold the OS just fine in this application, and to mount the really big USB memory separately would be a more optimum solution. That would also facilitate backups, both in the Pi and off-line in a faster device.