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Discourse is a very nice message board

published Nov 20, 2016 01:16   by admin ( last modified Nov 20, 2016 01:16 )



I really like it.

 


Read more: Link - Discourse


Extract a file with the dtrx command

published Nov 17, 2016 12:05   by admin ( last modified Nov 17, 2016 12:05 )

dtrx in Linux tries to extract any archive. It asks questions that can be a bit tricky and confuses case when doing so, but it seems to work fine.'

 

Untar a File in Linux/Ubuntu - HostingAdvice.com


Starting supervisord on Ubuntu 16.04

published Nov 15, 2016 10:35   by admin ( last modified Nov 15, 2016 11:29 )
# Make sure Supervisor comes up after a reboot.
sudo systemctl enable supervisor

# Bring Supervisor up right now.
sudo systemctl start supervisor

 


Read more: Link - supervisord - ubuntu server 16.04: cannot get supervisor to start automatically - Unix & Linux Stack Exchange


E-mail integration with chat, are there any good solutions?

published Oct 31, 2016 04:55   by admin ( last modified Nov 06, 2016 12:07 )

I need to set up a chat for a group where some people would prefer to use their e-mail.  For these people, any mail message they send, it should immediately be posted to the chat channel. For all chats posted in the chat room, there should be options to send them out to the e-mail recepient:

  • Ever time a chat is posted
  • In digest form, every
    • hour, 3 hours, days, 3 days or every week

 

It turns out to be hard to find such a solution. I am currently looking at Fleep - A messenger for your teams and projects which is it's own chat, and at Email to Slack – MailClark, your team’s bot for external communicationsk for Slack. So far this is what i have found.

  • I have invited a gmail address to Fleep, but that invite does not seem to reach the fleep mobile client for that person
  • I have not found a setting in Mail Clark for chat digests

There is also something called Zapier which is more of a toolkit and does not seem to have , but so far I am seriously thinking of creating one myself, but alas I do not think I have the time.


How to increase the contrast of Firefox tabs

published Oct 21, 2016 04:10   by admin ( last modified Oct 21, 2016 04:07 )

Apply this CSS somehow, for example through stylish:

.tabbrowser-tab .tab-label {     opacity: 1 !important;
  color: black !important;
  background-color: white; }




.tabbrowser-tab[pending], .alltabs-item[pending] {

    opacity: 1 !important;
  color: black !important;
  background-color: white;
 

}

 

If you use Stylish add this namespace line first:

@namespace url(http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul);

I used Firefox - style of inactive or unloaded tabs - Themes and Skins for Browser - userstyles.org as a template.


Keeping the top left part of a video

published Oct 20, 2016 12:49   by admin ( last modified Oct 20, 2016 12:49 )

ffmpeg  -i 20161019_171944.mp4 -qscale 0  -vf "crop=900:400:2000:600" cropped.mp4 0KB sq=    0B f=0/0

 

See more here: FFmpeg Filters Documentation


Beautiful Russian choir singing

published Oct 19, 2016 06:02   by admin ( last modified Oct 19, 2016 06:02 )

Also featuring octavist (basso profondo) singing

 

https://www.youtube.com/watch?v=MEYwu9F-YHc


Some interesting stuff from the Seed studio site

published Oct 13, 2016 10:15   by admin ( last modified Oct 16, 2016 12:02 )

GrovePi+ a Raspberry Pi hat that breaks out connectors for grove contacts. I think grove is basically a standard where you get power in conjunction with every pin on the development board. So it could be digital, analog and so on.

0.5 Inch OLED display Arduino shield for the Arduino micro form factor

Base Shield V2 A shield hat breaks out connectors for grove contacts. I think grove is basically a standard where you get power in conjunction with every pin on inthis case an Arduino or Arduino compatible. So it could be digital, analog and so on.

Screw Shield sturdier connections

Grove - Loudness Sensor

 


GraphQL: A new API standard

published Oct 12, 2016 01:26   by admin ( last modified Oct 12, 2016 01:26 )

GraphQL | A query language for your API

Looks interesting, as an alternative to REST or JSON-RPC.


How to convert a Google document into a presentation with CSS

published Oct 10, 2016 05:40   by admin ( last modified Oct 10, 2016 05:43 )

This trick uses pure CSS to make a Google document into a PDF slide presentation. Just export the doc to HTML and paste in the CSS code below.

What you will get

  • Title, heading 1 and heading 2 will be kept, and so will bulleted lists
  • Pretty much everything else gets hidden.
  • Each of title, heading 1 or heading 2 starts a new slide.
  • There will be a logo placed above each slide heading.

How to do it

Export your document to HTML

Open the HTML document and remove the style element inside the head element

Paste this style element in instead (it assumes your logo is in images/image00.png)

    <style type="text/css">
    p {
        display: none;
    }
    
    body {
        font-family: sans-serif;
    }
    
    p.title {
        display: block;
        font-weight: bold;
        font-size: 48px
    }
    
    
    @media print {
        h1,
        h2 {
            page-break-before: always;
            padding-top: 40mm
        }
        h1 {
            font-size: 42px
        }
        h2 {
            font-size: 36px
        }
        h1,
        h2 {
            background-image: url('./images/image00.png');
            background-repeat: no-repeat;
            background-position: left top
        }
    }
    </style>

 

Open the html file in e.g. Google Chrome

Open print dialog

Make sure "Background graphics" is ticked if you are using Google Chrome

Print to PDF

Open PDF in PDF viewer

Choose Presentation mode


The new Teensy boards (v 3.5 & 3.6)

published Oct 01, 2016 11:05   by admin ( last modified Oct 01, 2016 03:19 )

Teensy 3.5 & 3.6 by Paul Stoffregen — Kickstarter

Teensy are Arduino compatible microprocessor boards with a bit more oomph than Arduino. The new Teensies run on an ARM processor and at clock speeds above 100 MHz, while still beeing teensy in size.

The new Teens boards have a dedicated cryptographic co-processor that according to the PDFs linked below supports acceleration of the DES, 3DES, AES, MD5, SHA-1, and SHA-256 algorithms. So basically cryptographic hasing (SHA-256) and symmetric crypto (AES).

 

From the kickstarter page:

Technical Features & Specifications

Features specific to Teensy 3.6:

  • 180 MHz ARM Cortex-M4 with Floating Point Unit
  • 1M Flash, 256K RAM, 4K EEPROM
  • Microcontroller Chip MK66FX1M0VMD18 (PDF link)
  • USB High Speed (480 Mbit/sec) Port
  • 2 CAN Bus Ports
  • 32 General Purpose DMA Channels
  • 22 PWM Outputs
  • 4 I2C Ports
  • 11 Touch Sensing Inputs
 

Features specific to Teensy 3.5:

  • 120 MHz ARM Cortex-M4 with Floating Point Unit
  • 512K Flash, 192K RAM, 4K EEPROM
  • Microcontroller Chip MK64FX512VMD12 (PDF link)
  • 1 CAN Bus Port
  • 16 General Purpose DMA Channels
  • 5 Volt Tolerance On All Digital I/O Pins
 

Features common to both:

  • 62 I/O Pins (42 breadboard friendly)
  • 25 Analog Inputs to 2 ADCs with 13 bits resolution
  • 2 Analog Outputs (DACs) with 12 bit resolution
  • 20 PWM Outputs (Teensy 3.6 has 22 PWM)
  • USB Full Speed (12 Mbit/sec) Port
  • Ethernet mac, capable of full 100 Mbit/sec speed
  • Native (4 bit SDIO) micro SD card port
  • I2S Audio Port, 4 Channel Digital Audio Input & Output
  • 14 Hardware Timers
  • Cryptographic Acceleration Unit
  • Random Number Generator
  • CRC Computation Unit
  • 6 Serial Ports (2 with FIFO & Fast Baud Rates)
  • 3 SPI Ports (1 with FIFO)
  • 3 I2C Ports (Teensy 3.6 has a 4th I2C port)
  • Real Time Clock

Running scripts with passwordless sudo

published Oct 01, 2016 10:17   by admin ( last modified Oct 01, 2016 10:17 )

Quoted from the page  (Ubuntu ):

Shutting Down From The Console Without A Password

Often people want to be able to shut their computers down without requiring a password to do so. This is particularly useful in media PCs where you want to be able to use the shutdown command in the media centre to shutdown the whole computer.

To do this you need to add some cmnd aliases as follows:

Cmnd_Alias SHUTDOWN_CMDS = /sbin/poweroff, /sbin/halt, /sbin/reboot

You also need to add a user specification (at the end of the file after the "%admin ALL = (ALL) ALL" line so it takes effect - see above for details):

<your username> ALL=(ALL) NOPASSWD: SHUTDOWN_CMDS

Obviously you need to replace "<your username>" with the username of the user who needs to be able to shutdown the pc without a password. You can use a user alias here as normal.


 

Read more: Link - Sudoers - Community Help Wiki


If your Acer Aspire V-573G is hard to start

published Sep 27, 2016 05:35   by admin ( last modified Sep 27, 2016 05:33 )

That is, when you depress the start button on the left hand side, it sometimes has problem starting up, especially when not connected to mains, then in my experience you may need to get a new CR2032 battery on the mother board.

  • Remove the screws on the underside of the laptop
  • Pop off the bottom
  • Locate the battery (it's in the center)
  • Pop it out
  • Replace it with a new one

You should be grounded and it may be a good idea to disconnect the battery (the big one, not the coin cell we are talking about in this blog post) from the motherboard before beginning. The old CR2032 battery had a voltage of 2.94V as measured and a new one 3.04V. So maybe it started working better for another reason, or that difference is enough. Maybe the old one had an even lower voltage under load.


Byzantine fault tolerance paper from 1999

published Sep 23, 2016 01:05   by admin ( last modified Sep 23, 2016 01:05 )

"Oh Snap!" in Chrome and crashing Firefox: SSD or Ubuntu 16.04?

published Sep 20, 2016 10:55   by admin ( last modified Dec 31, 2016 09:29 )

One of my computers has for some time had the problem that tabs in Chrome get the "Oh snap!" message after a while, and Firefox just crashes mysteriously after many hours. This computer runs Ubuntu 16.10 and has an M2 SSD. Now my laptop is showing exactly the same behaviour, after having had an SSD installed.

I wonder if this is because the hardware isn't up to handling the speed of the SSD drives or if there is some kind of conflict between the SSD and the OS. I will slow down the SSD bus speed on the laptop and see if that helps.

Update 2016-12-31:

It helped!

 


Firmata - control & monitor the pins of e.g. an Arduino via USB

published Sep 19, 2016 10:05   by admin ( last modified Sep 19, 2016 10:05 )


Hashcash: Computational effort needed to access info resources

published Sep 19, 2016 09:50   by admin ( last modified Sep 19, 2016 10:09 )

Proof-Carrying Authorization links

published Sep 19, 2016 09:49   by admin ( last modified Sep 19, 2016 09:49 )

Artificial neural network links about Caffe

published Sep 19, 2016 09:49   by admin ( last modified Sep 19, 2016 09:49 )