smnv

Designing Data-Intensive Application, aka “The Boar Book” (kabanchik)

Stop drawing those pixels, people are dying!

https://www.snopes.com/fact-check/bono-of-contention/

From the consumer side:

I've bought a Qingping ClearGrass Air Monitor (CGS1). It costs about $100, but has CO2, tVoc, PM 2.5, PM 1.0, temperature and humidity sensors. From what I've read, sensors are quite good, people only sometimes complaining for bad fans, that need to be fixed after a year or so of use. Everything in one nice USB-C powered case with a sensor screen. A bit too much animation once a minute, that can't be disabled. Data is sent by WiFi.

There is a Qingping App for Android and IOS with some graphs and insight into values, but not much. It also can be integrated with Mi Home, but doesn't work for my region, and I can't get token to talk to it with python-miio, as in this habr example [1]. This example doesn't work too [2], looks like the api has changed.

So after a bit of sniffing I've made a simpler solution:

1. Installed Mosquitto MQTT Broker on my home gateway

2. Made a DNAT redirect of qing.cleargrass.com requests to this broker:

  iptables -t nat -A PREROUTING -i br-lan -p tcp -d qing.cleargrass.com --dport 11883 -j DNAT --to-destination 127.0.0.1:11883

3. Added a cron job of periodic subscribing for air monitor data. Without this message it doesn't push the data. The topic consists of some base64 uid and air monitor MAC address, I wrote it in square brackets, should be changed by end user:

  */5 * * * * /usr/bin/mosquitto_pub -h 127.0.0.1 -p 11883 -t '/[uid]/[mac]/user/get' -m '{"duration":"303","up_itvl":"2","type":"12"}'

4. Configured a mqtt_consumer in telegraf:

  [[inputs.mqtt_consumer]]
    servers = ["tcp://127.0.0.1:11883"]
    name_override = "air_monitor"
    topics = [
      "/+/+/user/update",
    ]
    data_format = "json"
    tag_keys = [
      "mac",
    ]

5. Created graphs and alerts in grafana. It was easier for me to create a further automation from there.

It is sad that there are still no easy way to connect everything in a "smart" home.

[1] https://habr.com/en/post/482352/#comment_21085236 [2] https://habr.com/ru/post/493220/

Edit: formatting

mtr -z? I mean, it is a good learning effort, but if someone doesn’t know about mtr, they should: https://bitwizard.nl/mtr/

Most receipts in my country have a qr code at the bottom with the link to the receipt in human and machine readable format. In the next year this will be mandatory for everyone. Russia.

mikrotik has capsman controller in all its gear, even without wifi. works quite nice, with roaming and such. cheap. boxes are ugly though.

What about http://cacti.net/ ? With Weathermap plugin it is quite good thing for performance monitoring. THold and Monitor plugins are for availability monitoring and alerting. It scales very good with Boost plugin, I had 3000+ hosts, 60000+ datasources with total poll time within one minute.

Many prefer Cacti to Zabbix because the latter is clunky and confusing compared to Cacti's simple straightforward approach with plugins.

But I am actually wondering, how alive is Cacti now, because its releases are constantly postponed, and forum is not as alive as it used to be.

Newer Cisco IOS versions (IOS XE for example) are running as a process in linux. Old IOSes were linux-based too. Don't mix up Cisco IOS with Apple iOS (which has roots in BSD).

it was more impressive last year, when he was talking for 3.5 hours while the most of the group stage games of quakelive tournament was played. there was only one quakecon stream allowed, so those games had to be democasted later.

i had a very mixed feelings: on one hand, listening carmack is very interesting, on another - i am a quake fan and wanted to see great games.

this year they have a separate stream for games, and it is great btw. absolutely top notch work from the faceit team: http://www.twitch.tv/quakecon

That can be a great movie plot.

This is simply not true.

Just want to add, that you shouldn't have full brightness and contrast on on your monitor in the daylight either. First thing I do with the new monitor is cut factory set brightness to half and then play with the contrast to make it comfortable. On some monitors you should want to cut brightness even more. At first it may seem not that comfortable, but after some time eye fatigue is much less.

Also, if you're using glasses, you need a little more brightness on your monitor.

And use correct light enviroment on your workplace! Side-facing light, the usual.

If you have a high myopia, Bates is useless. But it really helps when you have a little nearsightedness.

Given the progress in making of a LASIK machines, you should ask yourself: "Which LASIK machine is better?"

Doctor's work nowadays is just holding your head while the machine cuts the flap, burns your eye to the pre-calculated geometry and applies flap to it's place. And then a little correction of a flap, to make sure that it is in place.

So the parameters you should consider are:

- flap cutting method (by laser, sapphire blades etc)

- laser working diameter (should be more than your pupil's size, or you will have night and dim-light vision problems - halos)

- how calming the doctor is

- what emergency measures do they have is case of problems with the procedure or after-procedure complications.

You should get a good amount of pre-operation procedures and know of possible complications, and know, do you qualify for correction. There are a lot of conditions when you shouldn't have the procedure.

I had a high myopia. Really high, like huge glasses. I've made a wavefront-guided LASIK procedure three years ago, the most expensive one they got at the clinic. I have applied drops for one and a half months as per doctor's order and haven't used them since, I don't have the dry eyes problem. Drops, btw, are just antibiotics and steroids to speed up the healing process.

It takes time to get used to the new optics of eyes. I had near-sighted face mimics for about 18 months (you know that when you see a nearsighted person without glasses). I had sensed some fatigue in my eyes for an year. I still have halos at night and my astigmatism hasn't gone away completely. But I think, it worth the inconvenience.

I have a great vision, something like 20/20 by the measuring, but it's not like the one I had as a child, when I had a perfect vision. It's not THAT good, but it's better than glasses and contacts.

Think of LASIK not as a cure: it's just like a always-on contact lenses, but better. After all, it's just a cosmetic surgery.