Geiger Counter Kit Repair & Upgrades! Arduino Fun!

This video tells the story of how I went about repairing and adding some additional functionality to an old Geiger counter kit I purchased back in 2011. This is in no way meant to be a tutorial. This is more like a story. This could be seen as a tale of what NOT to do by some. :-D
I'm glad it's over and hope you enjoy!

Resources:
Why Do Geiger Counters Make That Clicking Sound?
https://www.youtube.com/watch?v=qtvz8lH5zhk

Original Kit I purchased (no longer available)
https://web.archive.org/web/20120118154518/http://www.goldmine-elec-products.com/prodinfo.asp?number=G18410

Schematic of kit above
http://chemelec.com/Projects/Geiger-Counter/Geiger-1.png

SBM-21 GM Tube
https://www.goldmine-elec-products.com/prodinfo.asp?number=G18160

LCD I2C Library used
https://www.arduino.cc/reference/en/libraries/liquidcrystal-i2c/

I2C Arduino Ref
https://www.arduino.cc/en/reference/wire

Arduino I2C Bus Scanner Sketch
https://playground.arduino.cc/Main/I2cScanner/

Code I modified
https://create.arduino.cc/projecthub/juliandwillett/customizable-geiger-muller-counter-e847d1

Case I modified
https://www.tinkercad.com/things/2A9Ge1qIA6a-geiger-counter-case-for-sbm-20

Type of LCD display I used
https://www.amazon.com/dp/B019K5X53O?psc=1&ref=ppx_yo2ov_dt_b_product_details

Opto-Couplers I used
https://www.amazon.com/dp/B01JG8EJVW?psc=1&ref=ppx_yo2ov_dt_b_product_details

DC-DC Isolated convert I used
https://www.amazon.com/dp/B09F3SR6W7?psc=1&ref=ppx_yo2ov_dt_b_product_details

Scope I purchased
https://www.amazon.com/Hantek-DSO5102P-Oscilloscope-Oszilloskope-Channels/dp/B071P97RLC

Thorium in Lanterns
http://large.stanford.edu/courses/2018/ph241/kinamon2/

Americium-241
https://en.wikipedia.org/wiki/Americium-241

Radioactive Boy Scout Story
https://harpers.org/archive/1998/11/the-radioactive-boy-scout/





Chapters
00:00 Intro
00:51 Fukushima nuclear disaster
01:15 Safecast
01:31 How do Geiger counters work?
02:11 Original kit I purchased
02:52 Searching/Finding/Repairing old lost kit
03:45 Testing kit with Thorium sample
03:56 Improvement wish list
04:52 Display
06:56 OLD Serial Arduino analog pins have silkscreen numbers backwards!
07:30 I2C Address finding tip
08:30 Killing an Arduino
09:31 New Arduino mini
10:29 Dead Arduino shows signs of life
10:40 Counting Clicks
11:20 Making the case
12:48 Final Assembly
13:37 Digital input trouble begin!
13:47 Redoing regulator/Arduino perfboard
14:17 Trying an opto-coupler on the counter input
14:57 Trying a DC-DC isolator
15:18 Bought an oscilloscope
15:42 Counter works with scope connected to input
16:14 Putting 2M ohm of resistance between input and ground fixes it
16:35 Swapping out LCD display because of failed backlight
17:11 Final code tweaks
17:26 Final Assembly 2nd Attempt!
18:10 Swapping in SBM-20 GM tube
19:13 Final testing
20:13 Americium-241 and the Radioactive Boy Scout
22:49 Closing