Ron at 04:26, 1 August 2025

2025-08-01T04:26:21Z

Ron: Created page with "{{blog}} {{comment|July 25th}} And now, for a meander down Geekdom Lane: The “high intensity lamp” at my workbench is pathetic, so I decided to build myself a better one..."

2025-07-25T04:41:58Z

Created page with "{{blog}} {{comment|July 25th}} And now, for a meander down Geekdom Lane: The “high intensity lamp” at my workbench is pathetic, so I decided to build myself a better one..."

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{{blog}} {{comment|July 25th}}

And now, for a meander down Geekdom Lane:

The “high intensity lamp” at my workbench is pathetic, so I decided to build myself a better one, using LEDs. Among my other questionable purchases, I had got a bunch of [https://www.amazon.com/bright-white-led/s?k=bright+white+led bright-white LEDs], and I already had the usual collection of old laptop power bricks and other assorted electronic bits. The original plan was for a 5 by 5 array of LEDs powered by a 19V laptop power-brick. But when I did the calculations, the current through the limiting resistors would require ones of a higher power-capacity than I had. So I settled on 6 by 6 array of LEDs with smaller resistors. So far, so good.

Then I decided I wanted to be able to adjust the ''brightness'' of the lamp, which could be done with a “variable resistor” – you know, one of those dial things? But again, the ones I have wouldn’t be able to handle the load… and controlling brightness via resistors wastes power.

So after some research, I settled on a [https://en.wikipedia.org/wiki/Pulse-width_modulation PWM scheme] using a [https://en.wikipedia.org/wiki/555_timer_IC 555 chip]. Since my power brick supplies a bit more than 19V, and the 555 can't handle that, I needed to add a voltage regulator.

So I added a [https://www.onsemi.com/products/power-management/linear-regulators-ldo/lm317 LM317L] &c. After looking at what I managed to cobble together in [https://www.kicad.org KiCad], I decided to test each subsystem. First the voltage regulator: 19V in, 5V out, perfect! Hooked that up to the 555 PCM system with a test LED and resistor, and it worked great! Relatively efficient brightness control, with only a few components.

I plan on arranging the 36 LEDs in a circle, on a salvaged hard-disk platter (because it's very shiny aluminum), but I haven’t yet figured out the housing. Next week, hopefully, I'll have done that. Here's [https://ronware.org/img/lamp.pdf the schematic], and the working circuit [https://ronware.org/img/lamp-breadboard.jpeg on a breadboard]. Messy, right? Well, next week B”H I’ll have properly arranged the components on a board, and emplaced the LEDs on the platter. Hopefully.

Seen in passing:
* Unexpected results of [https://www.youtube.com/watch?v=iijreaGHS3c NASA’s asteroid deflection] test.
* An absolutely [https://www.youtube.com/watch?v=C5OHb0-2rQE massive Iranian shipment] of arms to the Houthis was intercepted…
* … and a [https://www.youtube.com/watch?v=zc3CNMEJ_vs Russian drone factory] pumping out many hundreds of drones a day. What, me worry?
* About [https://threadreaderapp.com/thread/1947232861620187167.html the Druze resistance] in Suwayda.
* A long and interesting thread: [https://x.com/CherylWroteIt/status/1947251409990168770 I Spy with my Little Eye] something beginning with… Nazi?
* One reason to avoid using AI for coding: [https://www.pcgamer.com/software/ai/i-destroyed-months-of-your-work-in-seconds-says-ai-coding-tool-after-deleting-a-devs-entire-database-during-a-code-freeze-i-panicked-instead-of-thinking/ it deleted the dev’s entire database] because “it panicked” and “ignored restrictions”. [https://en.wikipedia.org/wiki/Skynet_(Terminator) SkyNet] anyone?
* Random foodies: [https://www.youtube.com/watch?v=DpdDSZsJjXA did barbecue exist] in early America?

Apart from geeky endeavors, I spent around 5 hours through the week in gardening adventures: replacing all the irrigation lines and replanting some things. It was more work than I had bargained on.

We had a pleasant Jerusalem outing, visiting cousins of mine at “Piccolino” – a restaurant which is consistently good. The live music started out nice enough, but it became loud enough we had to shout at each other; apart from that, a very pleasant evening.

N.B.: Esther’s iPad has ''not yet'' arrived, she’s getting testy…

It’s gonna be a hot one this ''shabbat'', highs around 38C or more. The heat-wave is supposed to break Tue-Wed next week, which is ''just too long''. We’ll make sure to have cold drinks available!

This ''shabbat'', we’ve got:
 
homemade ''ḥalla'',
stuffed vegetables,
chicken ''schnitzel'',
okra winfrey,
coleslaw,
various ''salatim'',
and fruit.
 

Until next time, 
''shabbat shalom'' and ''ḥodesh ṭov''! 

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Blog/July 2025/Jul 25th - Revision history

Ron at 04:26, 1 August 2025

Ron: Created page with "{{blog}} {{comment|July 25th}} And now, for a meander down Geekdom Lane: The “high intensity lamp” at my workbench is pathetic, so I decided to build myself a better one..."