Pi In The Sky

Simply a work area and/or catch-all for miscellaneous Raspberry Pi tips, tricks, tools, tweaks, research or harebrainers - most-likely a mess, but potentially useful to others. Initially weeding through remaining Raspberry Pi info @ ventures.tpedersen.net/errata/raspberrypi to salvage useful info.


Earmarked for migration - will see how much of this moves to this site

Harebrainers (potential recipes)


(Ongoing or Solved Issues/Oddities)

RPI 4 No HDMI Output

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

Pi Power

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!

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:

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!


(Stuff I should remember)

Check for Installable or Installed packages

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

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

SSH: Remove offending key when a IP is reused

ssh-keygen -R <ip>

Regular Expression (Regexp) Stuff

Stuff to Research

WiFi Bootstrapping : Comitup+Dietpi [Works!], Comitup+Q4OS [TBD]

I often make Pi's for others - pre-configuring them for WiFi in someone else's home is a pain in the drain!

Gave Comitup a quick once over - there was a downloadable image @ https://davesteele.github.io/comitup/. It looks to be JUST what I need AND it WORKS!

Posted experiences with the downloadable image (RaspOS that boots up with Comitup) in Raspberry Pi OS Alternatives.

I am currently exploring installing/incorporating Comitup packages into my projects as opposed to starting with the image because I use a variety of OS underpinnings - Q4OS, DietPi, Manjaro ... it (comitup-1.15-1) seems to be in latest RaspOS which should allow me to apt-get install on everything except Manjaro. I don't see it in Manjaro or Arch AUR

  1. Dietpi+Comitup:

    • Downloaded Dietpi ARMv6 32-bit. Uses the Raspbian package repository which provides comitup for install!

    • Booted on RPi4 to start with ... usual blow-by-blow

      • Auto updates itself & reboots - now at v8.3.1 - ~5min

      • Forced PW changes, disabled serial console

      • Dietpi config/software

        • Audio: Enabled, Sound card usb-dac (I'm going to mess with CutiePi enhancements)

        • Language/Regional: Locale en_US.UTF8, Timezone & us keyboard

        • Security: Set Hostname

        • Network/Adapters: Enable Wifi

        • Network/Other: Turned Off Boot wait for network (just to be safe)

        • Dietpi Software (season to taste: I installed stuff I want to live/play together): Shairport, Murmur, Raspotify, RPI.GPIO, python3, go, ALSA, GIT

      • Stuff I had to install by hand ... via ssh

        • My editor: good old joe - apt-get install joe

        • comitup from https://davesteele.github.io/comitup/ - apt-get install comitup
          // Whoops! WiFi was disabled by default in Dietpi, comitup choked during install - Make sure you add Network steps in dietpi-config above //

        • Whoops AGAIN! I forgot to RTFM @ https://github.com/davesteele/comitup/wiki/Installing-Comitup ... and I quote:

          • Allow NetworkManager to manage the wifi interfaces by removing references to them from /etc/network/interfaces.

          • Rename or delete /etc/wpa_supplicant/wpa_supplicant.conf.

          • The systemd.resolved service should be disabled and masked to avoid contention for providing DNS service.

          • The line dns=dnsmasq should not be in /etc/NetworkManager/NetworkManager.conf.

          • also changed default ssid in /etc/comitup/comitup.conf - now ap_name: <hostname>-<nnn>

        • I also added comitup to dietpi-services (right or wrong?)

        • comitup-cli is a useful command line tool here

    • Hey! It works!

  2. Q4OS+Comitup

    • <next in queue ... I'd think it would work, raspos-based>