April Diversions

It turns out that gri fins were invented in Russia, and are named after a Russian guy: https://en.wikipedia.org/wiki/Grid_fin

Get back to watching this Elon Musk interview where he drops a lot of shockers about Starship/BFR plans: https://twitter.com/Erdayastronaut/status/1385354692247658498

A Surprising update on the completion of some hardware for the new Russian space station: https://twitter.com/katlinegrey/status/1385582527788761090

Linux print nth line of file

I have to google this all the time. I guess that the following article answered it for me back in Nov 2020. The answer includes piping the output of head into tail, using sed, or using awk.

https://linuxhandbook.com/display-specific-lines/

Honestly, the unrelated hits from searching for this are fascinating in their own right:

https://www.bing.com/search?q=linux+print+nth+line+of+file

Laptop shuts down when sleep is selected

Investigating the issue of my work laptop sometimes rebooting when I try to use Sleep for travelling it. This is because Windows took the "Hybernate" option away, however I learned that it is possible to manually call the hyberbnate function from a CMD window using "shutdown /h". The rebooting while sleeping seems most likely to be due to damage to the laptop's motherboard.

This is an article titled with the exact problem that I was trying to solve. It had pretty much the same solutions as a lot of other related pages, which were to fiddle with power settings most of which I couldn't touch due to the group policy settings on my laptop: https://www.guidingtech.com/fix-windows-10-shuts-down-instead-sleep-hibernating/

I was unable to get around the group policies to try to turn off "fast startup". Here are a few searches that I tried on the topic. The hints, while unsuccessful, were interesting and I'd like to learn more:

turn off fast startup from command prompt: https://www.bing.com/search?q=turn+off+fast+startup+from+command+prompt&qs=AS&pq=turn+off+fast+startup+from+c&sk=AS1&sc=2-28&cvid=7C0CE2BE4176472982CB018F0BAC4ACA&FORM=QBRE&sp=2&ghc=1

powercfg -h off unable to perform operationhttps://www.bing.com/search?q=powercfg+-h+off+unable+to+perform+operation&cvid=de3e7676a2b54113b4fc6159bdf1b712&FORM=ANAB01&PC=U531

Assateague

Assateage Island has two camping options, the "National Seashore" and the state park. Both are pretty full of course.

Here's the pretty map for the National Seashore. Google confirms this: https://www.nps.gov/asis/planyourvisit/campground-maps-oceanside-and-bayside.htm

Managing my YouTube account

To upload, the first step is to log in. Use the desktop web page, do the log in that way, and look for the camera with the plus sign. This is a bit of a trick on a phone, but I can't find a way to do that exact thing on the moblie web page! It's probably a lot easier on the youtube app but I'm a dinosaur and don't feel like installing the app.

I have a subscriber! How can I find out who it was? This article gave me some ideas of where to click around: https://support.google.com/youtube/answer/7280745?hl=en

SSR Research

Looking into what SSRs are available on DigiKey, I found that a few of my assumptions about what I would find were mistaken. It turned out that the ones availble in the "Hockey Puck" package all have internal circuitry which was more complicated than the simple optocoupler example that I was expecting. Also I was surprised to find that nearly all of the SSRs available on Digikey were made by a single manufacturer, which is one I hadn't heard of before, Sensata-Crydom. That seemed to also be true on Mouser. The Sensata-Crydom SSRs that I checked the datasheets for all had fairly complex circuits for the LED side, and also had some kind of circuit to drive the mosfet on the switch side rather than having only a simple mosfet. In retrospect, it may have been too much to expect a "simple mosfet", and additional circuitry obviously helps with ensuring a solid relay switching function. For most SSR applications, such large amounts of current are typically being switched that there would be no reason to care about using a tiny bit of current to make the switch work. Also I learned that there are a few types of SSRs. In particular, some are MOSFET, others are BJT transistors. The BJT ones have a voltage drop across the transistor, as they do. The specs for these do not show an on resistance. Instead the forward voltage drop is listed. I found the following execellent tutorial that covers this:

https://www.allaboutcircuits.com/technical-articles/basics-of-ssr-solid-state-relay-the-switching-device/#:~:text=When%20the%20switching%20device%20of,on%2Dstate%20voltage%20drop%E2%80%9D.&text=Assuming%20a%201%20V%20drop,about%201%20watt%20per%20ampere.

Here are links to the datsheets for some of the SSRs that I found, with pros and cons noted:

An odd looking Sensata datsheet for the Crydom D06D SSR. Shows blocks for a "Control Circuit" on the LED side and a "Trigger Circuit" on the mosfet side. https://www.sensata.com/sites/default/files/a/sensata-d06d-series-panel-mount-datasheet.pdf

The Crydom datasheet for the D06D SRR. https://www.mouser.com/datasheet/2/657/d06d-series-dc-panel-mount-1371031.pdf

A datasheet for a different Crydom mosfet SSR, "DC series", shows a fairly similar internal circuitry. This has a nice contact cover: http://www.crydom.com/en/products/catalog/power-plus-dc-series-60-dc-panel-mount.pdf

Here's a Digikey page for yet another Crydom SSR. Why are there so many models and series available for Crydom SSRs?https://www.digikey.com/en/products/detail/sensata-crydom/D2D40/1771532

This TE SSR has a mosfet on the switch side, and a really simple LED circuit. There is a "mosfet driver" block that probably uses some power from the switched side, and the LED circuit may be an outright lie: https://www.te.com/commerce/DocumentDelivery/DDEController?Action=srchrtrv&DocNm=SSRDC&DocType=DS&DocLang=English

Another Crydom power plus datasheet. Looks like about the same circuits. https://www.mouser.com/datasheet/2/657/power_plus_dc_series_100_dc_panel_mount-1370752.pdf

A diffent series Crydom SSR. This is AC output and is a dual triac type. We don't want this: https://www.mouser.com/datasheet/2/657/gnssr-1063303.pdf

Here is a digikey search of all available ssrs with the hockey puck package, mosfet outputs, proper LED voltage range. I attempted to get a simpler output circuit by searching for ones with an allowed output voltage of 0V. I found that most of the returned results actually required at least 1V. https://www.digikey.com/en/products/filter/solid-state-relays/183?s=N4IgjCBcpgbFoDGUBmBDANgZwKYBoQB7KAbRAGYBWSgTgHZyQBdAgBwBcoQBldgJwCWAOwDmIAL4FYNBCGSR02fEVIUATDTVUQBchq0AGZm06Qe-YWMng1dWfMW4CxSGXIHKEXQBZyMgmBqYN5BOjZgnowB0n5qYXA0vt7xdJRBXuB0AByUBskEagbk5GBZYYXFIeVF5N5lBTV0Rg3FqdW1Bs0gFd4R1ZR0sPANg%2BR2I7CUwyBJQV1qGsGU5d40lFnTaqtZmuVZcMF7B%2BPd9LkZsL2wJ5elySwgHFy8gqISATQ79qiYTiquICMDyeZhelne3TAxW%2BCl%2ByhcZAMAAIAGpIgB%2BSLAnQAdMiUWF8RikYUDHjUYTUcTvLj8ZS0ZjcmS6QQiZjYMyKcDTCAAEpoUQ4ACqQgE7AA8igALI4NBYACufBwEKCtRhjnhqm8SIAtuKABY6rBhSi6g1Gk042Bmw3GgiUHFZG0WqTOu0gOhusJZHGmvW2sI0L0BZH%2Bl3gMDBmxRqEx61h91gT0J6pR9xRmlR3JR2BqGPYmPplMBahRuZlovm90aUNVsJUWsB%2B3Z4sgLKdL3crgisWSmVyxXK6wAWji0DkUH48s1AOWTHE1jHZCwhAwAgAJkisOw0OwcEilRg0ABPYwgeDjjdcVX5R48nsS6WyhVKsLsY%2BsZVmOXIBdAA

Do You Know Boogie-Woogie?

Some of my favorite

Old Lady playing unstoppably:https://www.youtube.com/watch?v=LGaCv4bJMQM