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John Bump
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Mad scientist
Mad scientist

5,768 followers
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https://belgianwaffleride.bike/ I'm considering this for 2019, based on friends who did it this year. 200 km, 1/4 dirt, 4 kilometers of climbing, as a race. That sounds like fun, right?
2018 Canyon Belgian Waffle RIde
2018 Canyon Belgian Waffle RIde
belgianwaffleride.bike
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The short version: doing taxes is hard because not only are there people who make money on taxes being complicated, but also there are people who are ideologically opposed to taxes being easy.
Intuit spent $13 million lobbying Congress from 2011 to 2015, with 41 lobbying reports relating to taxes in 2015 alone. Most of the reports reference lobbying to "enhance voluntary compliance" — a euphemism for opposing automatic filing.

In this, Intuit and other tax prep companies had a powerful ally: Grover Norquist. The anti-tax crusader vehemently opposes automatic filing on the grounds that it makes tax season insufficiently nightmarish, which might reduce people's aversion to taxes and make it easier for politicians to pass tax increases. So even though Ronald Reagan himself supported automatic filing, Norquist has helped make the idea dirt in the eyes of conservative legislators.
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I had no internet yesterday so instead I fixed things. While I was fixing stuff, I took a hint from quinndunki.com/blondihacks and 3d printed an adapter to stick my vintage scherr-tumico 0.0001" dial indicator on the quick change toolpost of my lathe. Now I can make sure the tailstock is correctly aligned after offsetting it, and I can center stuff in the four-jaw chuck to more precision than I could ever use.
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Today's question. I'm using a microcontroller to generate PWM in hardware, which is in the mhz-khz range. I want something in the microhertz range, so I need to do a 10000:1 divide. If I'm generating a PWM signal as the output from a PID control loop, and I divide the result by 10000, as in only transition the transducer signal every 10k input signals, what effects, other than massively slowing down the response time, will that have on a closed-loop control system? Any ideas on how to tune a control loop for this? (Obvious one being expecting significant integral wind-up.) Thanks for any advice. (And yes I could just do software PWM, especially at this speed, but the hardware's there and I'd rather use those cycles for other purposes.)
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How well does abs print onto cold, smooth abs? I'd like to print one or two layers onto an existing piece of injection-molded abs, which I can't really heat up throughout. (I may be able to heat the top surface with a hot air stream.)
Thanks for any advice.

I posted about using 3M spray adhesive to get wax filament to stick to the bed. The big problem with that is: when I go back to PLA, it sticks so well to the masking tape that in trying to pull a print off the bed, I ended up tearing the masking tape loose from the bed and then had to use a razor blade to scrape the remains off the PLA.

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This is the kind of thing +Eli Brandt might appreciate.
I've heard of insects (and plants) that use fire to their advantage. But I never knew that some insects take this to extremes, like actively finding burning logs. "Make no mistake: a lot of bugs do die during wildfires. Eggs, galls, immobile stages (like pupae) are cooked under most (but not all) circumstances, and some people take advantage of this to control pests.

However, some insects, like those living at the tops of trees, inside trees, or deep underground do survive.

This is where things get really interesting.
[...]
The beetle genus Melanophila, as well as a few other insects has infrared sensors in its legs which tell it where the fire is and how to get to it. It will actively seek out burning patches of forest, specifically to lay its eggs in trees which have been injured by fire and which aren’t in a position to fight off the invasion. Melanophila, Syntexis, and Acanthocnemus are notable because they’re frequently seen mating and laying eggs on logs that are still on fire.

To clarify: this doesn’t mean they’re recently burnt. I mean this literally…they’re known to lay their eggs on logs that are still actively burning. Acanthocnemus beetles are even attracted to smoldering ashes. Now, granted…they camp out on the non-burning portions, but it’s still pretty crazy.

These insects are interesting to entomologists, because we can use them to develop new technologies for sensing infrared signals. Even though these insects are small, Aradus sp. are less than 1/2 inch (they’re about 1 cm long), they can detect a fire from at least 3 miles (5 km) away."
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Years ago, while trudging through the ill-lighted back alleys of github, I found a bit of code that made a microcontroller into a Class D amplifier, by cleverly hardware-linking two pins, one inverted, to a PWM output, and driving a speaker. I had a cheap bidirectional motor driver sitting around so I ported the code to Arduino, hooked it up, and verified legible but atrocious sound coming out, once I level-shifted the microphone. I uploaded the code and walked away. Today I got email at my side job, from someone who has been playing with that code and through rewriting the ADC and PWM setups and using non-junk drivers, has managed to upgrade atrocious to merely poor sound quality. I'm not sure why I'm so tickled by this, but I love it that people take the effort to improve terrible ideas. Mostly I liked this project originally because it seriously blurred the line between software and hardware: the program consists of sticking lots of bits in lots of registers, then having a hardware interrupt move two bytes from the adc to the pwm. What people think of as "the program" consists of a semicolon.
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Parked Bench: Yellow Lane Lines Morph into Improbable Urban Seating
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Hey Internet Mac People. A friend gave me a Mac Mini that is still set up for her, as in it boots to her login. The Internet assures me that it's really easy to reset a Mac to factory configuration by simply holding cmd-R as it's booting. Or, since that doesn't work, hooking it to the internet and holding option-cmd-R. Or, since that doesn't work, holding shift-option-cmd-R. I have tried all of those with three different USB (the only option for interface) keyboards. Does anyone have any other suggestions for resetting a Mac Mini to its factory default configuration? I'm guessing get a replacement OS disc from Apple? Is there any way to make sure it'll actually boot off a cd rather than just continuing to boot off the default user configuration on the hard drive? I have no idea what OS version is installed because that doesn't show up on the login screen.
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