two factor mandatory for apple developers

Apple has started to force developers that want to develop and publish on the MacOS and iOS platform to enable two-factor authentication.

Two-factor authentication (also known as 2FA) is a type, or subset, of multi-factor authentication. It is a method of confirming users’ claimed identities by using a combination of two different factors: 1) something they know, 2) something they have, or 3) something they are.


When I just got around enabling it for one of the apple accounts I’ve got there seems to be a much much higher security barrier in place already…

That’s probably some sort of zero-factor no-authentication. I guess. Anyway: Kudos to Apple for finally forcing people to minimum standards. Properly integrating the second factor will make this so much simpler for users. Apples ecosystem solution already is quite well integrated.

Have you switched all your daily used services to two-factor authentication yet?

disaster warning!!! This is just a test.

Apparently yesterday somebody pushed the wrong button. Twice.

Like most countries Germany got a system in place to broadcast out warnings to the public in case of disasters or else.

And it proved to be quite useful in the past when it comes to the occasional storm or heavy snowfall/rain/lightning.

Seeing that they run a test and then again send out an apology to have run a test is puzzling and funny at the same time. Everyone has a “bad hair” day, right?

can your kitchen scale do this trick? – ESP8266+Load Cell+MQTT

Ever since we had changed our daily diet we started to weigh everything we eat or cook. Like everything.

Quickly we found that those kitchen scale you can cheaply buy are either not offering the convenience we are looking for or regularly running out of power and need battery replacements.

As we already have all sorts of home automation in place anyway the idea was born to integrate en ESP8266 into two of those cheap scales and – while ripping out most of their electronics – base the new scale functionality on the load cells already in the cheap scale.

So one afternoon in January 2018 I sat down and put all the parts together:

ESP8266 + HX711 + 4 Load Cells
my notes of the wiring… this might be different for your load cells…

After the hardware portion I sat down and programmed the firmware of the ESP8266. The simple idea: It should connect to wifi and to the house MQTT broker.

It would then send it’s measures into a /raw topic as well as receive commands (tare, calibration) over a /cmd topic.

Now the next step was to get the display of the measured weights sorted. The idea for this: write a web application that would connect to the MQTT brokers websocket and receive the stream of measurements. It would then add some additional logic like a “tare” button in the web interface as well as a list of recent measurements that can be stored for later use.

the web app. I am not a web designer – help me if you can! ;-)

An additional automation would be that if the tare button is pressed and the weight is bigger than 10g the weight would automatically be added to the measurements list in the web app – no matter which of the tare buttons where used. The tare button in the web app or the physical button on the actual scale. Very practical!

Here’s a short demo of the logic, the scale and the web app in a video:

You can grab the sourcecode for the Arduino ESP8266 firmware as well as the source code for the web application here.

fonts for your programming needs

We are looking at our screens more and more time of the day and most of that time we are reading or writing text. Text needs to look pretty for our eyes not to get sore – apart from the obvious “being able to tell what letter that is” there is a big portion of personal taste and preference when it comes to the choice of the font.

Most of the texts I am writing benefit from monospaced fonts.

This blog celebrates monospaced fonts for programming.
So many fonts have popped up in recent years.

Of course there’s a nice page available that previews the fonts right in your browser:

active noise cancellation does not suck on your eardrums

If you ever traveled on a train or plane with good active noise cancellation headphones you might agree how much more pleasant the trip was with much less noise reaching your ears.

When I tried active noise cancellation for the first time I had that weird sensation as if the pressure around suddenly changed. Like being in a very fast elevator or going for a quick dive. It felt weird but luckily it went away and the aww of joy replaced it. Quietness. Bliss.

Now there seem to be people for whom that feeling won’t go away. They get headaches and cannot stand the feeling when using active noise cancellation.

I’ve never had any explanation to this phenomena – until now. I ran across an article on SoundStage describing that in fact the feeling is not caused by actual changes of pressure but…

According to the engineer, eardrum suck, while it feels like a quick change in pressure, is psychosomatic. “There’s no actual pressure change. It’s caused by a disruption in the balance of sound you’re used to hearing,” he explained. 

eardrum suck – the mystery solved

Aha! The brain gets confused by signals reaching your ears that naturally would not exists. Those signals make no sense so the brain tries to make sense of it. And voilá something is sucking your ear drum!

LED projector for your home automation needs

In 2017 Texas Instruments had released a line of cheap industry grade LED projectors meant to be used in production lines and alike:

DLP® LightCrafter Display 2000 is an easy-to-use, plug-and-play evaluation platform for a wide array of ultra-mobile and ultra-portable display applications in consumer, wearables, industrial, medical, and Internet of Things (IoT) markets. The evaluation module (EVM) features the DLP2000 chipset comprised of the DLP2000 .2 nHD DMD, DLPC2607 display controller and DLPA1000 PMIC/LED driver. This EVM comes equipped with a production ready optical engine and processor interface supporting 8/16/24-bit RGB parallel video interface in a small-form factor.

Texas Instruments

And of course this got picked up by the makers. In the hands of people like MickMake who designed an adapter PCB for the RaspberryPi Zero W to the smallest projector available from TI.

After I had learned about the existence of those small projectors I had to get a couple and try for myself. There would be so many immediate and potential applications in our house.

2x DLPLDCR2000EVM with MickMake adapter and RaspberryPi Zero W

After having them delivered I did the first trial with just a breadboard and the Raspberry Pi 3.

first light!

The projector module has a native resolution of 640×360 – so not exactly high-pixel-density. And of course if the image is projected bigger the screen-door effect is quite noticeable. Also it’s not the brightest of images depending on the size. For the usual use-cases the brightness is definitely sufficient.


  • too low brightness for large projection size – no daylight projection
  • low resolution is an issue for text and web content – it is not so much of an issue for moving pictures as you might think. Video playback is well usable.
  • flimsy optics that you need to set focus manually – works but there is no automatic focus or alike.


  • very low powered – 2.5A/5V USB power supply is sufficient for Pi Zero + Projector on full brightness (30 lumen)
  • low brightness is not always bad – one of our specific use cases requires an as dim as possible image with fine grain control of thr brightness which this projector has.
  • extremely small footprint / size allows to integrate this device into places you would not have thought of.
  • almost fully silent operation – the only moving part that makes a sound is the color wheel inside the DLP module. You have to put your ear right onto it to hear anything.
  • passive cooling sufficient – even at full brightness an added heat sink is enough to dissipate the heat generated by the LED.

So what are these use cases that require such a projector you ask?

Night status display:

For the last 20+ years I am used to sleep with a “night playlist” running. So far a LED TV was used at the lowest brightness possible. Still it was pretty bright. The projector module allows to dim the brightness down to almost “moon brightness” and also allows to adjust the color balance towards the reds. This means: the perfect night projection is possible! And the power consumption is extremely low. A well watchable lowest brightness red-shifted image also means much lower temperatures on the projector module – it’s crazy how low powered, low temperature.

at 75% brightness (camera did not properly focus…)

Season Window Projection:

Because the projector is small, low-powered and bright enough for back-lit projection we tried and succeeded with a Halloween window projection scene the last season.

outside view
inside view

It really looks funky from the outside – funky enough to have several people stop in front of the house and point fingers. All that while power consumption was really

House overall status projections:

When projecting information is that cheap and power efficient it really shines when used to display overall status information like house-alarm status, general switch maps, locations of family members and so on. I’ve left those to your imagination as these kind of status displays are more or less giving away a lot of personal information that isn’t well suited for the internet.

Head Up Display esthetics

Many cars these days come with head up displays. These kind of displays are used to make information like the current speed appear “floating” over the street ahead right in your field of vision.

This has the clear advantage that the driver can stay focused on the street rather than looking away from the street and to the speedometer.

As practical as it seems these displays are not easy to build and seemingly not easy to design. Every time I came across one it’s built-in functionalities where limited in a way that I only can assume not a lot of thought had gone into what exactly would the driver like to see and how that would be displayed. There was always so much left to desire.

Apparently the technology behind these HUDs is at a point where it’s quite affordable to start playing with some ideas to retrofit a car with a more personal and likeable version.

So I started to take a look at what is available – smart phones have bright displays and I had never tried to see what happens when you try to utilize them to project information into the windshield. So I tried.

As you can see – bright enough, readable but hazy and not perfectly sharp. The reason is quite simple:

“In the special windshield normally used, the transparent plastic safety material sandwiched in between the two pieces of glass must have a slight and very precise wedge, so that the vehicle operator does not see a HUD double image.”


There are some retrofit adhesive film solutions available that claim to help with that. I have not tried any yet. To be honest: to my eye the difference is noticeable but not a deal-breaker.

So I’ve tried apps available. They work. But they do a lot of things different from how I would have expected or done them. They are bearable, but I think it could be done better.

tldr: I started prototyping away and made a list of things that need to be done about the existing HUD applications.

mirrored basic html prototype, not well adjusted, just to play…

Here’s my list of what I want to achieve:

  • display orientation according to driving direction – I had expected all HUD applications to do this. They know the driving direction. They know how the device is oriented in space. They can tell which direction the windshield is. They know how to correctly turn the screen. They do not do that. None of them.
  • fonts and numbers – I cannot stand the numbers jumping around when they change up and down
  • speed steps interpolation – GPS only delivers a speed update every second or so. In this time speed might jump up and down by more than +1. The display has 60 fps and gyros to play with and interpolate… I want smooth number transitions.
  • have an “eco-meter” – using gyros the HUD would be able to display harsh accelleration and breaking. Maybe display a color-coded bar and whatever is measured is reflected in the bar going left or right…
  • speed-limit display – apparently this is a huge issue looking at the data availability. There seems to be open-street-map data and options to contribute. Maybe that can be added.
  • have a non-hud mode – non mirrored to use for example to set speed limits and contribute to OpenStreetMap this way!
  • automatically switch between HUD and non-HUD mode – because the device knows it’s orientation in space – if you pick it up from the dashboard and look into it, why not automatically switch?
  • speed zones color coding – change the color of the speed display depending on configurable speed regions. 0-80 is green, 80-130 is yellow, 130-250 is red.
  • turn display off when car stopped – if there’s nothing displayed or needs to be displayed, for example because the car stopped the display can be turned off completely on it’s own.

Navigation is of limited value as the only way I could think of adding value would be a serious AR solution that uses the whole windshield. Now I’ve got these small low-power projectors around… that get’s me thinking…

What would you want to have in such a HUD in your car?

sakura season forecast

I am visiting Japan for almost 7 years now but I’ve never actually been there when the famous cherry blossom – or sakura – was in full force.

As every year there’s a forecast map for this years season and it gets updated frequently:

picture not showing japanese cherry blossoms

reward driven speed limits

As you might know I am living in Germany. Germany is the one country where you have some roads that are legally not having any speed limit whatsoever. If the circumstances allow to safely drive 250 km/h you are allowed to do so. It’s up to the drivers judgement.

Now as much as this is a great thing of personal freedom it also has some negative side effects on the climate.

Your car is burning a lot more fuel when driving those kind of speeds. And a lot meaning that it resembles more an exponential curve than a linear line. Rule of thumb: 2x the speed is more than 4x the consumption.

Ever once in a while people start discussing about a general speed limit for Germany – as every other country has it. Some talk about 160 km/h, some about 120 km/h.

The motivations are diverse: climate, resource use, safety, …

In any case additional limits would need to be enforced. More speed traps…

A.Savin (Wikimedia Commons · WikiPhotoSpace)

What if things would be handled differently?

How about this:

Politics would introduce a “best speed lottery”. On every street without a speed limit there would randomly be speed controls and speed traps. Those who follow the best practices of driving … Let’s say 120 km/h… Would be rewarded when randomly photographed. The reward would be a tax discount on car tax and/or gas tax and one ticket put into the countries lottery pool. Once a quarter a new electric car or similar would be given to a random winner.

What would you think would make people drive slower in their own motivation?

try to read/listen to japanese

I am at the stage of “trying to comprehend” the japanese spoken language.

I’ll be a happy camper if I would understand most of what is being said and could follow daylight normal conversations pointed towards me japanese. Like, you know, when trying to make a purchase or having to ask for that one bit of information.

For this, apart from excessive exposure to the spoken language, I am using some tools to help with reading to a small degree.

For those completely out of the loop:

Japanese has no genetic relationship with Chinese, but it makes extensive use of Chinese characters, or kanji (漢字), in its writing system, and a large portion of its vocabulary is borrowed from Chinese. Along with kanji, the Japanese writing system primarily uses two syllabic  scripts, hiragana (ひらがな or 平仮名) and katakana (カタカナ or 片仮名). Latin script is used in a limited fashion, such as for imported acronyms, and the numeral system uses mostly Arabic numerals alongside traditional Chinese numerals.

Here’s a list:


icon this blog

I’ve written about the progressive web application functionalities provided by this blog. But I’ve missed to explain in all simplicity what it means for most of you trying to read.

This is where Volker explains in simple terms what to do:

Step 1: Tap this icon in your browser:
(maybe someone can send me an android icon that does this?)

Step 2: Find and tap on “Add to Home Screen”
Step 3: give the icon a name

Enjoy the quick access to this blog.

power consumption after the ssd swap

A week after swapping out mechanical hard drives for SSDs it’s time to look at what it meant in the longer run for the power consumption of the server.

15 watt less at least

Depending on what the server is asked to do – high or low cpu load and so on – the power consumption fluctuates but it’s very visible that the averages are about 15 watt lower at all times. Great!