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0x402DF854 | 5 years ago | on: Apple to kill Epic’s accounts on Friday the 28th

From a preliminary statement of Epic's motion:

> Just over two weeks ago, Apple’s CEO Tim Cook was asked during a Congressional hearing whether Apple has “ever retaliated against or disadvantaged a developer who went public about their frustrations with the App Store”. Mr. Cook testified, “We do not retaliate or bully people. It’s strongly against our company culture.”

0x402DF854 | 5 years ago | on: Your DS18B20 temperature sensor is likely a fake, counterfeit, clone

I am having troubles understanding your reply. You're saying that these counterfeit sensors cannot be used for anything critical with "meaningful skin in the game", which is an obvious statement. In fact, depending on definition of "critical" and "skin in the game", one can make an argument that authentic DS18B20 sensors also aren't good enough. So what?

This whole story about not using things where they shouldn't be used is like saying "don't use an arduino on a chemical plant". Thanks, we get it.

> The key operator that I see here is "beyond the limits", to which Maxim engineers appear to have done a fair job of specifying

Except that limits are not well specified since they depend on too many factors (ambient temperature, parasitic cable capacitance, noise pickup, etc). These are recommendations on improving reliability, not hard guarantees. I'd recommend actually reading that note.

> If your long 1-wire network works today but not tomorrow, then it's difficult to swallow attribution of the issue to a singular authentic component constrained by documented performance specs rather than the system's overarching design.

This is again a trivial statement. Where did I claim the opposite?

If a weather monitor equipped with 1-wire devices has intermittent communication issues, do you immediately replace the entire system? Good luck with that proposal :)

If you replace your 1-wire driver on the above mentioned system to the one with active pullup and issues go away, do you still scrap the system because it's "out of spec" according to recommendations?

> Since practicing engineers don't have the leisure of independently validating every bit of specified electrical minutae, we generally have to extend some level of trust to what the component vendors specify in datasheets unless presented with evidence to the contrary (because bugs).

Again not sure what's the point of this trivial statement. Yes, bugs. I, "practicing engineer", have the leisure to independently validate datasheets when required. I also rely on them when I can. So what?

> especially given all the effort to demonstrate and document that the physical implementations of these counterfeits are clearly different...which renders the reference datasheet null and void in its entirety...

I invite you to research re. FDTI-gate and its widespread use, including medical devices.

Are you comfortable using light bulbs purchased from amazon in your kitchen without looking at the reference datasheet?

If I need an accuracy of +/- 5 degrees for not critical monitoring purposes, can I use "counterfeit" DS18B20 sensors?

If I need an accuracy of +/- 0.1 degrees for critical monitoring purposes, can I use "authentic" DS18B20 sensors?

Answers are as obvious as your statement.

> which I therefore conclude nothing about these counterfeit sensors can be trusted in any application with meaningful skin in the game

Your subjective "meaningful skin in the game" doesn't tell much. What sensors do you trust? Do you require calibration certificates traceable to a secondary standard for each component for them to be blessed for "application with meaningful skin in the game"?

0x402DF854 | 5 years ago | on: Your DS18B20 temperature sensor is likely a fake, counterfeit, clone

You are indeed missing something here :)

Long 1-wire networks are notoriously unreliable [1]. Something that works fine today can stop working tomorrow. That doesn't mean that they shouldn't be used anywhere. They have their niche.

If I want my heating system monitor to report temperatures once per hour and it takes me 5 tries and 10 seconds to read a sensor, I call it good enough. If monitor doesn't succeed after 20 retries, it sends an alert to replace the sensor (so far that only happened due to damaged wiring, not the sensor itself).

It is possible (and quite fun) to build reliable systems using somewhat reliable components :)

[1] https://www.maximintegrated.com/en/design/technical-document...

0x402DF854 | 5 years ago | on: Your DS18B20 temperature sensor is likely a fake, counterfeit, clone

That, or they slap huge markups for these otherwise unpopular products.

Try to find a popular 16-bit ADS1115 ADC on digikey. They offer SMD 10X2QFN chip for $8, 10VSSOP for $10, assembled adafruit board for $22 (!!!) or DFRobot board for $15 (exact same board is half the price on ebay).

In comparison, ADS1115 boards from aliexpress are $2.

0x402DF854 | 5 years ago | on: Your DS18B20 temperature sensor is likely a fake, counterfeit, clone

I've bought ~100 of these sensors from ali and ebay and 9/10 had troubles reporting temperatures in passive mode reliably. However simply repeating requests until sensor reports a valid value (!=+85C and !=-127C) works fine. Rarely I've seen sensors not working in passive mode at all.

Still, I always recommend running an extra +VDC wire (3 wires vs 2 wires isn't a big inconvenience). When running large 1-wire buses (>100m long, dozens of sensors each), a dedicated power line is always a must.

Another funny use for these sensors is a source of nonce/id. Weirdly, every single DS18B20 I've bought had a unique ROM address, even when I got large batches. I still PTSD about that batch of PCIE network cards with identical MAC addresses...

0x402DF854 | 5 years ago | on: The most famous loop: the Carnot Cycle

This is a false historical analogy wrongly applied to a vague case of "business loops". Neither Carnot nor Clausius defined entropy as "disorder", they defined it as a coordinate of thermal interaction since it became clear that temperature isn't a coordinate, but instead a potential. The "disorderliness" character of entropy as a thermodynamic parameter came later.

Anyone who uses entropy interchangeably with "disorder", "chaos", etc. might be interested in reading this: https://aapt.scitation.org/doi/10.1119/1.5126822

The term "disorder" is defined much less rigorously then "entropy".

> The second insight in here is that if you allow the ebb and flow of disorder, your loop can pass between high and low potential energy states a lot more efficiently.

Regarding these ideas of letting "chaos-entropy" prevail in your business for short period of times only to bring it back to order and use the effects of "potential energy variations" to get higher outputs... Sounds like an excerpt from a poorly written pseudo-management textbook purchased for $19.99 at an airport kiosk.

0x402DF854 | 5 years ago | on: Specific ways to write better Python (2017)

I don't quite enjoy "explicit mathematically dense" code, it leads to bad habits, see item 4: Python's syntax makes it all too easy to write single-line expressions that are overly complicated and difficult to read.

If you really need to pack a lot of math, just define it in a module (e.g. tensorflow does that nicely).

I've had an intern who came from MATLAB. Convincing them to stop packing numerical constants in the middle of every expression was unexpectedly difficult. "But it's shorter that way!"

0x402DF854 | 5 years ago | on: Windows 10 2004 issues: Now browser bugs hit

> Microsoft is investigating a bug that causes Chromium-based Edge to automatically launch when Windows 10 version 2004 starts up, while Firefox and Chrome users are also reporting issues with this version of Windows.

If my laptop was to launch a browser every time I boot into windows 10, I wouldn't even consider this a bug. Yesterday after a simple reboot (no updates, no new software or drivers, no nothing) my jack audio output stopped working (works fine in debian). Go figure.

0x402DF854 | 5 years ago | on: GitHub isn't fun anymore

Never had any "fun" with github either. I have had my account since 2013 and I've just learned about this "trending page" thing. Can anyone explain what's it useful for?

0x402DF854 | 5 years ago | on: FFmpeg 4.3

I use FFMPEG as a thermostat to keep my apartment nice and warm :) I encode all of my videos (phone, DSLR, dash cameras) to h265 on my Ryzen workstation when it's not use. I have a primitive "PID-controller" script pulling temperatures from influxdb (data collected using a few esp8266 with ds18b20 sensors) and adjusting -threads parameter accordingly. It automatically adjusts presets (slow, veryslow, placebo, etc) depending on number of videos in the queue, so it never runs out of material to encode :) It saves me from using stinky baseboard heaters and reduces my HDD bills!
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