Feb 02

Running Adafruit Feather HUZZAH ESP8266 with external power supply (3.3V / 5V)

Usually you use a usb cable to power and programAdafruit Feather HUZZAH ESP8266 via the mini usb port:

But what if you want to use external 3.3V (or 5V) power supply? To which pin should you connect it?

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Jan 19

How do Sonoff devices work?

A while ago Jan Almeroth have done excellent research on how Sonoff devices operate. Thanks to his (and many others’) work, projects like SonOTA are now possible. I’ll try to summarize the information in this article.

1. Overview

It appears that sonoffs areIoTgocompatible devices.IoTgo platform was created by Itead and aims to facilitate easier integration between IoT devices and Applications.It mainly consists of three parts:

  1. Devices ⇔ Server (left part) – devices connect to the server via HTTP/WebSocket, register and update their parameters. The server can send control commands using push notifications (via WebSocket);
  2. Apps ⇔ Server (right part) – IoTgo Apps use server gather information about devices (+their status) and control them;
  3. Web interface ⇔ Server (not shown) – used for device management;

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Jan 18

What is Sonoff and how to configure it

Remote switches, Internet of Things (IoT) and Smart home in general are quite trendy nowadays. There are plenty of trademarks and devices that allow you to switch lights, heating, garage doors etc via an application on your mobile / web page.

There is one very popular gadget among the Smart housers – the Sonoff. It is actually a trademark that includes various kinds of remote switches. Sonoff devices are getting more and more popular these days because they are small, cheap, cloud ready, easy to use and have built-in AD/DC converter (i.e. no external power supply is needed, just a cable to plug it in the grid). Some sonoffs can be controlled via RF keyfobs.

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Jan 10

Dynamic Objects in Active Directory

Sometimes we need to create users/groups/computers in Active Directory that will be used temporary (by a contractor, for testing etc.). The typical workflow is: Create > Use for a while > Delete. The deletion is manual and often these objects are being forgotten which poses some security risks.

It is little known fact that we can create the so called Dynamic objects (DOs, a.k.a. temporary objects) that get deleted from AD automatically when the associated TTL expires. Microsoft added this capability in Windows Server 2003. In fact the “Dynamic object” is an auxiliary class (OID = When linked to an object it adds some new attributes like the entryTTL (Entry-TTL) and ms-DS-Entry-Time-To-Die attribute.

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Jan 05

WinRM would not listen on port 5985

The WinRM was configured to allow remote administration via a GPO but it wouldn’t let us connect with Enter-PSSession. The firewall rule was there passing the traffic on TCP port 5985.

Checking WinRM config showed something strange:

Listener [Source=”GPO”]
Address = *
Transport = HTTP
Port = 5985
Enabled = true
URLPrefix = wsman
ListeningOn = null

So WinRM was actually configured but wasn’t listening on any network interface. Why?

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Jan 03

What is Add-PrinterDriver actually used for?

As of Windows 8.1 / Server 2012 R2 there is one beautiful cmdlet -Add-PrinterDriver. It dramatically simplifies driver/printer installation.

Naturally you will be tempted to install a driver from an .inf file like this:

But you will be blamed:

So it does not work as you/we may think. Sigh… So then what it is used for?

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Dec 30

Running Linux on Windows 10


Often developers and related OPs need to test stuff on Linux (web, cli, .NET Core etc.). The typical approach was to spin up a Virtual machine (VM), install and configure a Linux distro and play with it.

Main Cons include: you need a hyper-visor software, enough RAM, fast hard drive, to fight with basic operations like cope-paste text and files between machines etc.

Well, good news! As of the Anniversary Update Windows 10 supports the so called “Windows Subsystem for Linux” (WSL). It allows you to run natively* most of the non GUI Linux stuff**on Windows without the overhead of a virtual machine.

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Dec 29

How to enable Night Light feature on DisplayLink devices in Windows 10

Windows 10 Creators Update comes with a cool new feature called “Night Light“. It allows you to warmer the colors of your monitors during dark hours (or in a dark room) so your eyes feel more comfortable (programmers will appreciate it much!). It supportsf.lux‘s basic functionallity, but now it is a built in Windows 10 feature. Great!

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Dec 21

Matching Windows disk to VM disk in VMWare

UPDATE 2018-02-12: The script below has some issues. I found better version here:https://communities.vmware.com/thread/548671

Those who have experience in VMWare know that there is no 1 to 1 match between VM’s disk number and the disk inside guest OS.

You can use this script to export disk mappings to grid or to a csv file:https://github.com/PKGeorgiev/PowerShell-VMWare/blob/master/Get-VmDiskToWindowsDiskMapping.ps1

This script is a slight modification of Conrad’s version with some improvements:

  1. Allow pipelining
  2. Use Guest’s hostname in all WMI calls instead of VM’s name (they can differ)
  3. Formatting and error checking

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