Pi In The Sky

 Oct 2021:  First RPI Hardware issue?!  SmartiePi RPI4 board from June 2021 has lost ability to emit HDMI signal.  Runs fine if I SSH into it, but cannot get HDMI output to save my life!   Pi has been used headless for past 6 months or so.  When reconnected to HDMI there is NO signal/output.

22 October:  FIXED!  It was the damn CASE!  NO hdmi cable or adapter would work (and I tested a quite a few!).  Finally removed the case and POOF!  The cable clicked in a nano farther and it came right up!   VERY bizarre, RPI 4B was mounted in that case the day it arrived, worked fine right out of the box!  I can also see the case is no longer available on Amazon.

Others w/ similar issues

• Watching this chatter:  https://www.reddit.com/r/raspberry_pi/comments/qc4jad/did_i_damage_my_raspberry_pi_4_hdmi_issues/

• Firmware could do this?  https://github.com/raspberrypi/firmware/issues/1548.  Have now worked with fresh SD/OS, updated/upgraded everything including eeprom.  https://jamesachambers.com/raspberry-pi-4-bootloader-firmware-updating-recovery-guide/

Mini Project - A tangent while on my quest to build CamperPi that will provide low-power/offgrid entertainment.  I also have a pile of questionable RPi power supplies that need to be weeded through - I keep plugging in bad ones!  THEY NEED TO BE TOSSED!

Jan 2022 - Built a contraption to test cables and PSU's ... I had a mess on my hands!

• Stumbled upon ....

  • Article/Script to test power supplies AND CABLES:
    @ https://bia.is/2019/02/02/raspberry-pi-check-your-power-supply/

  • Some VERY GOOD background info:
    @ https://ownyourbits.com/2019/02/02/whats-wrong-with-the-raspberry-pi/

  • Another good article (and script):
    @ https://jamesachambers.com/measure-raspberry-pi-undervoltage-true-clock-speeds/

  • Official Power Supply Requirements:
    @ https://www.raspberrypi.com/documentation/computers/raspberry-pi.html#power-supply

  • Breakdown of vcgencmd output:
    @ https://harlemsquirrel.github.io/shell/2019/01/05/monitoring-raspberry-pi-power-and-thermal-issues.html

Built new TesterPi image 

1. Raspberry Pi Imager:  Download/burn Raspberry Pi OS Light

2. Configure, install & boot

   • Raspi-Config:  Hostname, WiFi, password, localisation & turn on ssh

   • apt-get update, then apt-get full-upgrade

   • installs (editor and sysbench):  apt-get install joe sysbench 

   • sudo reboot

3. via ssh:

   • Created ps-check.sh using script @ https://bia.is/2019/02/02/raspberry-pi-check-your-power-supply/
     Sysbench 1.020:  Slight mod to CPU syntax in script.  Now looks like this:
     sysbench cpu --cpu-max-prime=10000000 --threads=4 run  &

   • May as well bring in my tester2.sh over too ... script I used for Pi benchmarking

   • Also created picheck3.py python3 code using sample script from jamesachambers and the code from page on harlemsquirrel site.  Stuck it on github to see how that works too @ https://github.com/tped/PiPower

Initial tests:  Ghadzooks, this is interesting!  I knew I had some crappy cables, but many surprises here ... 

1. The Legrand Wall Outlets* I had installed in my work area are worse than I thought ... periodic undervoltage on RPI3B+ w/ known good cable

2. My USB Tester/Multimeter* sucks power (of course it does!  :facepalm:) ... one step forward, two steps back!

3. Most of my USB-2 to Micro USB cables were pretty bad ... BUT worth saving for RPi 1B, 2 and RPi 0W

4. Canakit 3.5amp PS w/ PiSwitch* is probably my favorite for RPI 4 projects.   Good price ($10) & solid

5. Argon ONE Raspberry Pi 4 USB Type C Cable Power Supply | 5ft 5.25V/3.5A*.  Works great, little more $$ and no on/off switch

6. Smraza 5.1V 3A Power Supply for RPi 4 with ON/Off Switch & USB-C->MicroUSB adapter*.   Doesn't look durable, but works fine w/ 90 degree plug to fit in a tight spot!

7. Throttling is not necessarily a problem:  $h1t does happen!  Example, our HomePi is rock solid, it runs and has done it's job for years ... a few reboots/year for updates and such.   Over the course of months, vcgencmd reports that it has had at least one Under-Voltage, Arm Frequency Cap and has been Throttled ... the Pi is doing its job!

8. RPI 0W seems like it would run kodi videos using a hamster & wheel for power!   Quite amazing ... everything seems to power it!  Primary finding of this testing - CamperPi is now a RPi 0W and plays HD movies and Duke Nukem using a 5v 550mA power supply!

Find a specific package via apt-cache search <package>

List of ALL installed packages (pipe to grep or page thru) via dpkg -l

ssh-keygen -R <ip> 

I will always need all the help I can get here ....

This month's fav tool @ https://regex101.com/

Python Regex @ https://www.w3schools.com/python/python_regex.asp

Regular Expression Analyzer @ http://xenon.stanford.edu/~xusch/regexp/

Regexp builder @ https://regexbuildertool.com/

Interesting Regexp Generator @ https://regex-generator.olafneumann.org

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions/Cheatsheet