3
points
abirkill
Joined 149 karma
[ my public key: https://keybase.io/abirkill; my proof: https://keybase.io/abirkill/sigs/ChP31BIVjRTWkY03dHtvqUNu_4PI_ebmCAqRBVDyvJ4 ]
- This is not a dissimilar system to Teletext[1], which transmitted data in the blanking interval of a broadcast TV signal, and could be interpreted by a TV or other hardware with appropriate support. Teletext was pretty widespread throughout Europe in the 1980s and 1990s.
It was typically used to transmit pages of information (news, weather, etc.) that could be viewed directly on the TV, but the BBC's Ceefax[2] Teletext service was also used to distribute software to the BBC Micro, when equipped with the appropriate Teletext Adapter[3].
In a similar fashion to the Sega Channel system, the Teletext system would broadcast looped data, with popular pages (such as news and weather) being repeated frequently so they would load quickly, and less popular pages taking longer to load (or more accurately, to wait for the next time they appeared in the looped data).
I was interested to see that the Sega system used a bitrate of 8Mbps, which sounded pretty high for the mid-90s, but I see that Teletext had a bitrate of almost 7Mbps for PAL broadcasts, despite being roughly 15 years older!
[1] https://en.wikipedia.org/wiki/Teletext
[2] https://en.wikipedia.org/wiki/Ceefax
[3] https://en.wikipedia.org/wiki/BBC_Micro_expansion_unit#Telet...
- I can't speak to the cloud provider support, as I don't use it, but they have supported scheduled backups since at least June 2019, as I have locally-stored backups from scheduled Takeout jobs going back that far.
Bear in mind that the scheduling support is extremely basic -- the only option available is to schedule six exports, one every two months. You can't change the frequency or the number.
Also, you can't pick when the schedule starts, so if you want backups every two months indefinitely, you have to remember to schedule the next set of backups two months after the final backup of the previous scheduled job finished.
It's better than nothing, but only just.
- There were also several others, including some live shows, all of which can be found on the BBC's Computer Literacy Project Archive: https://clp.bbcrewind.co.uk/
During one of the live shows, demonstrating e-mail, the e-mail account was hacked, probably the first hack captured on TV: https://www.vice.com/en/article/9ak7w5/as-seen-on-tv-when-ha...
- I think the speed that things can go wrong when using a table saw (or most power tools) is faster than some people, including some woodworkers, might expect. There's a good example video here (warning, shows a very minor injury):
https://www.reddit.com/r/Carpentry/comments/11s6zlr/cutting_...
While we're still not talking microseconds, I think it highlights that moving the blade out of the way needs to happen very quickly in some cases to avoid serious injury.
- As a counter-example, I haven't had an entirely successful Google Takeout export in at least a couple of years, using their service to schedule the exports automatically every two months.
I always have a failure with Google Fit data, which reports 'Service failed to retrieve this item' on the same JSON file every time. I assume this is something corrupted at their end.
It's not that uncommon for my exports to intermittently show failures with other services -- for example, my latest export, taken on April 20th, also failed to include one of my YouTube videos, with the same 'Service failed to retrieve this item' error. That video is usually included successfully, so I'm guessing this was a glitch.
Nothing major, but I can well believe that others also experience regular errors, although I'm sure we're in the minority.
- This is true, but I don't think any consumer-grade sensor systems offer this as an option? I guess it might be useful if you're building your own sensor, and can't afford/justify a dual-NDIR sensor.
My understanding is that with single-NDIR sensors (like the MH-Z14 and 19), the auto-calibration is intended to overcome gradual particle buildup and beam degradation in the sensor chamber. While disabling it will prevent the scenario I described, you'll instead end up with gradual sensor shift as the sensor ages. I guess this could be minimised by manually calibrating the sensor outdoors on a regular basis.
Dual-NDIR sensors split a single beam into two chambers, so any degradation of the sensor beam affects both measurements, and the particle buildup in both chambers should also be approximately equal over time, so they should remain accurate over an extended period without any requirement for calibration. I built mine about 4 years ago and I do occasionally check to make sure they read ~400ppm when placed outdoors, last check was around 420ppm which suggests they're behaving reasonably well as they age.
- That's a shame, they've worked well for me. Unfortunately I can't recommend any others without doing some research, I found quite a few dual-NDIR sensor modules when I was looking and chose this one primarily based on availability and a reasonable datasheet.
A sibling post[1] mentioned a sensor that is listed as being dual-NDIR so should give reliable readings, and has a USB interface, so that sounds like one possibility.
- The auto-calibration systems on cheaper consumer sensors also cause issues if they rarely see air that has low CO2 levels. Because these sensors can't measure absolute CO2 levels, only relative CO2 levels, they provide an absolute figure by looking for the lowest CO2 concentration they've seen over a period of time, usually around a 72 hour rolling window.
This works acceptably if the sensor is frequently exposed to outdoor air, but in a residential environment that's not always guaranteed, particularly in winter when it's not uncommon to keep windows closed to retain heat. In these situations the sensor will consider the lowest level to be around ~400ppm, even if it's actually much higher. This, of course, scales all other readings, so a sensor might read between 400-800ppm, leading you to believe everything is fine, when the actual indoor range is 800-1600ppm.
Because the auto-calibration happens over a period of time, it can be quite difficult to determine that your sensor is misreading, and the only way to fix it is to expose it to fresh air to reset the baseline.
The best solution I found to this is a dual-NDIR sensor which measures two different light frequencies, one which is absorbed by CO2 and one that isn't. This allows the sensor to know the absolute CO2 concentration, rather than the relative CO2 concentration, and avoids the need for auto-calibration. (I believe for absolute accuracy it still needs calibration for altitude, but for consumer use this makes such a small difference to be irrelevant).
Unfortunately, when I last looked, I couldn't find any consumer-grade sensors which used dual-NDIR sensors, only more expensive and less aesthetic commercial sensors. In the end I built my own using a CDM7160 sensor connected via I2C to a ESP8266, which reports over MQTT.
- Out of the three vaccines in use in both Canada and Europe, it appears that Canada entered agreements as follows:
Europe entered agreements as follows:Moderna: August 5th, 2020 [1] Pfizer: August 5th, 2020 [1] AstraZeneca: September 25th, 2020 [2]
I couldn't immediately find data on the quantities ordered, but this doesn't seem to support the claim that Canada was slow in placing orders?Moderna: November 25th, 2020 [3] Pfizer: November 11th, 2020 [4] AstraZeneca: August 27th, 2020 [5][1] https://www.canada.ca/en/innovation-science-economic-develop...
[2] https://pm.gc.ca/en/news/news-releases/2020/09/25/new-agreem...
[3] https://ec.europa.eu/commission/presscorner/detail/en/ip_20_...
[4] https://ec.europa.eu/commission/presscorner/detail/en/ip_20_...
[5] https://ec.europa.eu/commission/presscorner/detail/en/ip_20_...
- From the second paper[0]:
'In order to provide more information about event severity within the S1 designation, S1 severity events have been separated into two columns in Table 1 based on whether each event is of sufficient severity to result in actual or simulated airbag deployment for any involved vehicle. Of the eight airbag-deployment-level S1 events, five are simulated events with expected airbag deployment, two were actual events involving deployment of only another vehicle’s frontal airbags, and one actual event involved deployment of another vehicle’s frontal airbags and the Waymo vehicle’s side airbags. There were no actual or predicted S2 or S3 events'
[0] https://storage.googleapis.com/sdc-prod/v1/safety-report/Way...
- They're using the ISO 26262 scale for severity, not their own: https://en.wikipedia.org/wiki/ISO_26262#Part_9:_Automotive_S...
- Another interesting example is Hyder, Alaska, which is only accessible by road from BC, Canada. It relies on various services from Canada, including ambulance and fire services, the latter due to Hyder's fire hall being burnt down, with their fire engine inside, during an Independence Day fireworks display.
There are no border controls when entering Hyder from Canada, as the only way to access the rest of Alaska from Hyder is via seaplane, and those flights are treated as international in origin when they land. There is a inspection station when crossing into Canada, but it is closed overnight -- anyone wishing to enter Canada when its closed must report via videophone.
- From the location of those light sources, I suspect they are from drilling rigs extracting oil from several large oil fields around the Grand Banks of Newfoundland.
There's a map of the largest fields in this article:
http://www.cbc.ca/news/canada/newfoundland-labrador/husky-we...
- If you're simply looking for capacitive touch in a consumer environment, then there are a great many. Simple capacitive touch sensors to replace physical push-buttons were widely seen in the 80s, I remember using them on elevators, and built one myself as a child.
Capacitive touch sensors that registered an X/Y position rather than a simple on/off state were also common in laptop touchpads from around the mid to late 90s. The iPod introduced a capacitive touch wheel to replace the click wheel in their second-generation model, released in 2002.
There were various capacitive touchscreen display devices around before the iPhone, but probably the most relevant to your query (and one of the most well-known, due to its similarity to the first iPhone's technology) was the LG Prada, a phone with a capacitive touch-screen announced about 6 months before the iPhone.
The thing with the iPhone's touchscreen wasn't that the technology was particularly revolutionary -- sure, if you combine enough words together, then you can make the argument that the iPhone was probably the first mass-consumed capacitive multi-touch hand-held consumer device, but you can remove any of those words and it was no longer the first. The revolutionary aspect of the iPhone was, in my opinion, the software that allowed the device to be controlled with the relative imprecision of a finger, rather than a stylus. The actual hardware to process the touch inputs was at best evolutionary, not revolutionary.
- If yours also claim to be manufactured by American Paper Optics, as the pair in the parent comment claim to be, the (real) manufacturer has some information to help determine if they're counterfeit:
https://www.eclipseglasses.com/pages/safety
See the photo at the very bottom of the page for an illustration of the (very minor) differences.
- Many libraries have received glasses for free from the Space Science Institute, which is a reputable organisation funded by NASA, the National Science Foundation, and others.
There's a map of libraries on their website:
http://spacescience.org/software/libraries/map.php
If yours is on that list, you should be pretty safe, I think.
- This isn't limited to glasses. I purchased a 12x12 sheet of solar filter film from a seller on Amazon, manufactured by Thousand Oaks Optical (who are listed on the American Astronomical Society's list of reputable vendors), and I'm also being refunded.
I checked the Thousand Oaks Optical site and they have a list of legitimate resellers of their products, and the Amazon seller I used is listed. I'm surprised Amazon didn't do the same basic checks before e-mailing me.
When I was searching for more information after receiving the e-mail, I also found someone on an astronomy forum[1] who is being refunded for a telescope that appears to retail for around $1199.
[1] https://www.cloudynights.com/topic/587658-amazon-eclipse-gla...
- As an example, the Vestas V164-8MW seems to be one of the largest off-shore wind turbines, and has a rotor diameter of 164m and a rotational speed of between 4.8 and 12.1rpm. [1]
Unless I'm miscalculating, that means that the tip of one of the rotors will travel 515 metres per revolution, which at 4.8-12.1rpm is a tip speed of between 2,472 metres per minute and 6,231 metres per minute.
To put that in more common units, that's between 148km/h and 373km/h.
[1] https://stateofgreen.com/en/profiles/vestas/solutions/v164-8...
- 3 points
- 2 points
- I had the same issue with the seat edge, I believe that it's referred to as a waterfall edge. The rest of the chair was great, but I found that extremely uncomfortable after a few hours. Many people don't have a problem with it, however.
I also recommend Steelcase as a good alternative. I considered the Leap but eventually chose the Gesture, and am extremely satisfied.
- 4 points
- YouTube's stabilisation option attempts to remove (with reasonable success, in my experience) rolling shutter wobble caused by camera movement, although I don't believe it will mitigate the effect of a moving subject.
There was a talk at last year's Google I/O with some examples:
- Not all houses in the UK have numbers, especially in rural areas. If you don't live in a village or larger, it's pretty common to have a house name, and no number. (Edit: I just checked the village I grew up in, and was surprised to find that out of 48 houses covered by the postcode, 41 of them only have a house name, no number -- I'd have guessed closer to a 50/50 ratio).
Even in cities, it's not particularly unusual to have houses that don't have numbers, especially older houses -- in my parents' postcode, two of the houses only have a name.
House names are fully supported by correctly implemented postcode lookup systems -- for example, in the common online use-case where you enter your postcode and a list of houses is brought up, the list will include the houses that only have name identifiers.
- 2 points
After a couple of high-usage outlets got jammed to the point that nothing could be plugged in, I replaced them with ones from the hardware store, and they are a big improvement. The existing outlets are unbranded, and I guess were from a bulk box of the cheapest that the electrician could source.
In my experience, Leviton are OK (much better than what was originally fitted), but Eaton are great -- they require slightly more force than non-TR outlets, but they're consistent, reliable, and I've never had to try more than once to plug anything in.