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Category Archives: Notes
Building The Marauder LowRacer From Bike Parts
I have a new post on Hackaday: Building The Marauder LowRacer From Bike Parts.
Mail Call #34: Project Boxes, Power Adapters and Power Switches from AliExpress | In The Lab
This post is part of my video blog and you can find more information about this video over here.
You can support this channel on Patreon: patreon.com/JohnElliotV
Silly Job Title: Electricity Guardian.
In this video we take a look at what has arrived in the mail from AliExpress.
I mention about a project I’m working on: Electronics Project #13: Sanyo AM/FM Digital Clock Radio RM6018 Teardown Part 1.
Here is a list of the stuff that arrived:
- 90x65x36mm
- 108x56x40mm
- 82x52x35mm
- NEWEST 1pcs Figure 8 IEC 320 IEC320 iec C7 to C8 90 Degree Left & Right Angled AC Power Adapter Male Female Extension connector
- 5Pcs Honyone MR-6B 15x21mm 4Pin ON-OFF DPST Mini Rocker Switch 12A/125VAC 10A/250VAC
- 5/20Pcs KCD4 Switch DPST 4/6Pin ON OFF Rocker Switch Toggle Switch with Led Light 16A 250V AC 25x31mm (Red 4PIN, 5PCS)
- 5/20Pcs KCD4 Switch DPST 4/6Pin ON OFF Rocker Switch Toggle Switch with Led Light 16A 250V AC 25x31mm (Red 6PIN, 5PCS)
- Red Mushroom Cap 1NO 1NC DPST Emergency Stop Push Button Switch AC 660V 10A Switch Equipment Lift Elevator Latching Self Lock (5pcs)
Thanks very much for watching! And please remember to hit like and subscribe! :)
Following is a product I use picked at random from my collection which may appear in my videos. Clicking through on this to find and click on the green affiliate links before purchasing from eBay or AliExpress is a great way to support the channel at no cost to you. Thanks!
Yum Cha Mini High-Precision Electronic Scale notes |
Let’s go shopping!
Destroying single disk ZFS zpool
This is a note for Future John. I followed the instructions from ChatGPT. They looked reasonable enough. Now I have a spare 2TB SATA drive that has no purpose in life. I am always sad when things have no purpose in life. Who knows. Maybe one day…
-------------------
Tue Jul 01 03:33:54 [bash:5.2.15 jobs:0 error:0 time:0]
root@charisma:/home/jj5
# zpool status sata
pool: sata
state: ONLINE
config:
NAME STATE READ WRITE CKSUM
sata ONLINE 0 0 0
ata-ST2000DM008-2UB102_ZFL7BGR8 ONLINE 0 0 0
errors: No known data errors
-------------------
Tue Jul 01 03:34:00 [bash:5.2.15 jobs:0 error:0 time:6]
root@charisma:/home/jj5
# zpool destroy sata
-------------------
Tue Jul 01 03:34:08 [bash:5.2.15 jobs:0 error:0 time:14]
root@charisma:/home/jj5
# cat /proc/partitions
major minor #blocks name
...snip...
8 48 1953514584 sdd
8 49 1953505280 sdd1
...snip...
-------------------
Tue Jul 01 03:34:23 [bash:5.2.15 jobs:0 error:0 time:29]
root@charisma:/home/jj5
# wipefs -a /dev/sdd
/dev/sdd: 8 bytes were erased at offset 0x00000200 (gpt): 45 46 49 20 50 41 52 54
/dev/sdd: 8 bytes were erased at offset 0x1d1c1115e00 (gpt): 45 46 49 20 50 41 52 54
/dev/sdd: 2 bytes were erased at offset 0x000001fe (PMBR): 55 aa
/dev/sdd: calling ioctl to re-read partition table: Success
-------------------
Tue Jul 01 03:34:58 [bash:5.2.15 jobs:0 error:0 time:64]
root@charisma:/home/jj5
# sgdisk --zap-all /dev/sdd
Creating new GPT entries in memory.
GPT data structures destroyed! You may now partition the disk using fdisk or
other utilities.
-------------------
Tue Jul 01 03:35:28 [bash:5.2.15 jobs:0 error:0 time:94]
root@charisma:/home/jj5
# parted /dev/sdd --script mklabel gpt
-------------------
Tue Jul 01 03:35:50 [bash:5.2.15 jobs:0 error:0 time:116]
root@charisma:/home/jj5
# wipefs /dev/sdd
DEVICE OFFSET TYPE UUID LABEL
sdd 0x200 gpt
sdd 0x1d1c1115e00 gpt
sdd 0x1fe PMBR
-------------------
Tue Jul 01 03:36:02 [bash:5.2.15 jobs:0 error:0 time:128]
root@charisma:/home/jj5
# lsblk /dev/sdd
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
sdd 8:48 0 1.8T 0 disk
-------------------
Physics
This is what doing physics looks like. Theoretical physics, that is!
New Book Teardown #7: Electricity and Magnetism 3rd Edition (2013) | In The Lab With Jay Jay
This post is part of my video blog and you can find more information about this video over here.
You can support this channel on Patreon: patreon.com/JohnElliotV
Silly Job Title: Prime Hack.
In this video we tear down Electricity and Magnetism 3rd Edition written by Edward Purcell and David Morin and published in 2013.
Electricity and Magnetism is one of the books I am taking notes for as a part of my Learning the Art of Electronics project. These notes are a perk for people who support me on Patreon, so what are you waiting for!? :)
There is a website for the book maintained by the publisher, but regrettably there’s not much there, just some material available to instructors only: https://www.cambridge.org/Purcell-Morin
I mention two xkcd comic in the video, those are these: Farads and Nerd Sniping.
The “esu” is prounounced as “eee-ess-you” and is also known as the Statcoulomb.
I mention the Franck–Hertz experiment which happens to be something I wrote a Hackaday article about: A DIY Version Of The Franck-Hertz Experiment.
The first edition of Electricity and Magnetism was volume two in a five volume course: Berkeley Physics Course.
The books mentioned in Chapter 1 include The Flying Circus of Physics and How Things Work.
The websites mentioned in Chapter 1 are:
The Feynman (1977) reference is to The Feynman Lectures on Physics which is also available here: www.feynmanlectures.caltech.edu
The symbol: ∇ (“nabla”, an upside down Δ “delta”) is the vector differential operator and its key uses are:
- ∇f → gradient of scalar
- ∇·F → divergence of vector field
- ∇×F → curl of vector field
- ∇² → Laplacian
The Big Clive video that I mentioned was this one: How a stungun creates 20kV from a 9V battery.
I also mention the show’s wiki, the ITL Wiki, which is on the web over here: https://www.inthelabwithjayjay.com/wiki/
Thanks very much for watching! And please remember to hit like and subscribe! :)
Following is a product I use picked at random from my collection which may appear in my videos. Clicking through on this to find and click on the green affiliate links before purchasing from eBay or AliExpress is a great way to support the channel at no cost to you. Thanks!
AIRAJ 3-Pcs 7-inch Locking Pliers notes |
Let’s go shopping!
New hard drives
Yesterday I was talking to my friends on IRC about how I should use a proper RDBMS for ad hoc data analysis more often. Then I found myself a job.
The hard disks I use for my offsite backups are ready to be replaced. They are good reliable drives (Western Digital Ultrastar 8TB) but they have been in service for five years and the warranty is just about to expire.
So I wanted to get some new drives which will do me for the next five years. I needed to know: what are good reliable drives to buy?
It turns out Backblaze maintains Hard Drive Data and Stats.
I downloaded their data for Q1 2025 and wrote a few scripts to process it. The output was this report:
The first drive listed in the above report is an SSD, but I want an ordinary spinning rust HDD. The second drive listed is ST12000NM000J which is Seagate Exos X18 12 TB. I found them on Amazon for AU$499 and on eBay for AU$280. So I purchased three drives from eBay.
Time well spent. Thanks d0nk`! <3
Making GameCube Keyboard Controller Work With Animal Crossing
I have a new post on Hackaday: Making GameCube Keyboard Controller Work With Animal Crossing.
The Greeks
I use old iPhone 6 smartphones in my lab as computers with small screens. I use them to display notes while I’m working. Recently I added some notes about the Greek letters:
How To Make A Beautiful Floral Keycap Using Resin
I have a new post on Hackaday: How To Make A Beautiful Floral Keycap Using Resin.
https://www.youtube.com/watch?v=07K_nX6TEoE