Archive for the ‘General’ Category.

Today’s Metal Porn: A Tool Cutting Steel

What I learned on Imgur today:
Slow motion close up of a steel cutting tool

Those little splotchy marks on the metal being cut are grains. The boundaries between grains is where cutting is preferred. Notice how the tool doesn’t do the cutting, rather the material being cut creates a dead zone in front of the tool and does the cutting, increasing tool life. When this buildup breaks away, a burr is formed. Also, the shavings that are formed during cutting tell a lot about the quality of cut and if the rake angle, speed or feed of the cutting must be altered.

Network Television is Irrelevant

Last night I was a little surprised that the first hit I found for the Obama speech was NPR but I pressed on. Today I read that none of the big networks, ABC, NBC, CBS and FOX carried the speech. Of course, it makes sense they’d all pass on the presidential speech since it’s sweeps month, there’s a lot of very important fiction that needs watching this month.

It is now official, network television is now irrelevant.

It’s been said that the revolution will not be televised. I didn’t think this would be the reason why.

Obama’s Speech On Immigration

Obama’s Speech on Immigration tonight is pretty important. Watch it.

Workshop Weekend Invitation!

Registration for December’s Oakland Workshop Weekend is now open!

Join us on December 6 & 7 to solder, sing, make ice cream, learn about mechanisms, program in JavaScript, Python, Clojure, or visually, remotely control an Arduino and more. At Workshop Weekend, a flat $40 admission gets you as many workshops as you can handle!

Register online by Wednesday, November 19 and save $10 with code EARLYBIRD1795.Select your workshops at

For families coming to Workshop Weekend together, we’re keeping our $10 discount for all parent admissions with the purchase of two or more admissions for children (under 18). Sign up on the same account and the discount will be automatically applied.

We have 30 workshops to choose from at this Workshop Weekend — a few old favorites are coming back alongside a number of new electronics, papercraft, and wearables workshops — and more! Join us for:

Register and select workshops online at

I hope we’ll see you in December!

J.D., Gil, and the team at Workshop Weekend

Reminder to Self: Cancel Account

Reminder to self: cancel my account. Their long history of misogynistic ads belittle women.

My Godaddy account is paid up through most of 2015. I’ll be switching in a few months.

I made this decision in 2012 and will follow through with it. You might want to do the same.

LED Lighting That Drives You Crazy

Here’s something you won’t be able to unsee: The next time you are driving at night behind a car, flit your eyes left and right. The brake lights of the car in front of you might cast long streaks of flickering on your retinas. Many of the new LED lights are more like strobe lights, flicker in an insanely distracting way… on the highway and in people’s homes.

LED string lights are the worst. In shopping centers and restaurants and on Christmas trees. Just move your eyes around a little and ZOWIE, you’re in a disco with streaks of strobe lights all around you! I’ve heard that it actually causes epileptic seizures in a small percentage of people. For me, it just makes me hate you and your incessant strobe lights in my face. I’ll admit that the effect isn’t too bad as long as I keep my head and eyes perfectly still. :-(

Can’t tell if your light is flickering? Try this: close one eye and wiggle your finger in front of the bulb. You’ll see the strobe effect very clearly.

Oh Lee, you’re exaggerating / crazy / over-sensitive!

Actually, I’m not. Try googling “LED flicker“. Let me point out to some sources

Here’s an IEEE workgroup formed to work on the problem of high-brightness flickering LED bulbs and their 2010 work-in-progress document whose purpose is “…to describe health implications of flicker”

This article in LEDs Magazine promotes good techniques for manufacturers to use in making good LED lighting because “…people are beginning to pay more attention to long-term exposure under higher-frequency flicker in the 70–160-Hz range. Such flicker can cause malaise, headaches, and visual impairment.”
(LEDs Magazine April/May 2014, Proper driver design eliminates LED light strobe flicker)

Here’s a guy on Youtube that tests LED bulbs on his own time. One of his tests is to check whether bulbs flicker. Some of the big brands flicker, some of the no-name brands don’t. Ugh, there are no standards.

Here’s a snippet from a US Department of Energy publication “Low-frequency flicker can induce seizures in people with photosensitive epilepsy, and the flicker in magnetically-ballasted fluorescent lamps used for office lighting has been linked to headaches, fatigue, blurred vision, eyestrain, and reduced visual task performance for certain populations. Flicker can also produce hazardous phantom array effects—which may lead to distraction when driving at night, for example—or stroboscopic effects, which may result in the apparent slowing or stopping of moving machinery in an industrial setting.”

etc etc etc…