validate email with PHP

How to validate email with PHP

“How to validate email with PHP” is conceptually part of a bigger problem: accurately validating web forms including emails without sacrificing good UX. I’ll blog about that some other time. This post presents and dissects PHP code to validate email. The explanations and my reasoning should allow you to adjust the code to your needs […]

Building an IoT Node for less than 15 $

Review “Building an IoT Node for less than 15 $”

In this article I am going to review the book ”Building an IoT Node for less than 15 $” by Claus Kühnel. TL;DR “Building an IoT Node for less than 15 $” is the book I wish I had had when I started my endeavor into the IoT/ESP8266/NodeMCU world in May 2015. I covers everything […]

Adafruit Feather HUZZAH with ESP8266 and LiPo connector

New Adafruit ESP8266 development board with LiPo connector

Looks like I need to update my popular article about ESP8266 development boards once again. I just found out that Adafruit sells what seems like a really cute development board with LiPo connector: the Adafruit Feather HUZZAH ESP8266, what a name. The ESP module seems to be an ESP-12E, it’s definitely got 4MB flash memory. […]

How to enable OS X screen sharing from the command line

After a recent OS X update mangled my Mac Mini’s sharing setting I had to learn how to enable OS X screen sharing from the command line. Here’s how. One of the first articles my favorite search engine turned up was blog post on It’s really helpful and attracted a few comments which give further […]

Eclipse Mars auto-scroll lock

Eclipse Mars introduce a terribly annoying feature that you can’t even turn off, sigh. If you now scroll up in the console Eclipse automatically activates scroll-lock. Hence, if you just browse the console output scroll-lock will be ON when you’re down browsing and leave the console. How awful is that? The implementation was triggered by […]

Smiley on an MAX7219 8x8 LED matrix connected to NodeMCU dev kit 1.0

NodeMCU with MAX7219 8×8 LED matrix display

Since the awesome devsaurus recently fixed important SPI issues (#50 is from Christmas 2014!) in NodeMCU it’s now possible to run MAX7219 8×8 LED matrix displays with an ESP8266 and the NodeMCU firmware. Constraint: at the time of this writing (2015-20-22) SPI for MAX7219 worked fine only with then current NodeMCU dev and dev140 branches! As of mid November 2015 the necessary changes are […]

MacBook power adapters from China - 60W-T-tip

MacBook power adapters from China

The other day I ordered two MacBook power adapters from China. My last 60W MagSafe power adapter for MacBook Pro had died a sudden death. Since it was the T-tip that was broken I considered it beyond repair. Here’s a quick report how I’d rate those MacBook power adapters from China. I ended up ordering a 45W model and two 60W […]

WiFiMCU: NodeMCU with Cortext-M4 instead of ESP8266

WiFiMCU: a NodeMCU dev kit with a Cortex-M4 chip

DOIT, the Doctors Of Intelligence & Technology, ride the ESP8266 NodeMCU wave a bit differently. The have been producing 2nd generation ESP8266 NodeMCU development boards for a while now. Recently they developed a new kit that uses more or less the same board but with a Cortex-M4 chip instead of an ESP8266. It goes by the […]

Comparison of ESP8266 NodeMCU development boards

A comparison of ESP8266 NodeMCU development boards must inevitably also compare the ESP8266 chips used on those boards. The comparison can be confusing not because there are many different boards (there’s only 3) but because there are several names for the same thing. Since this article has become quite long, and to give you an […]

Man is a sick breed

Before you read on let me make one thing clear, “man is a sick breed” makes no distinction between sexes. Man in this context refers to humans. The older I get the more convinced I am that humans are a sick breed, a degenerated form of life that at some point in the past branched-off from (other) […]