Heart Rate Trackers

Recently I acquired one of the new fitbit alta HR bands, mainly because it promised to track my heart rate 24/7 without the need to wear any chest strap.

I always expected this to be less accurate than a chest strap, but how much less? I also happen to have a Polar H10 chest strap (which I use when running), so I decided to record with both for an extended period today.

The results are below (click for the full image):

The fitbit is in blue, the Polar strap in green. There are a few gaps in the data …

Linux on the Alienware 13 R3 (2017)

I recently bought a new laptop because my trusty old Thinkpad (x230) finally got a bit too old for my taste (apart from the battery it still works perfectly though!).

After a lot of searching around and gnashing of teeth - how can current laptops be barely faster than my 4 year old Thinkpad?! And what do you mean, the laptop comes with at most 16 GB of RAM and I can't even upgrade it?!

Finally, I settled on the Alienware 13.

As a gaming laptop, it has a quad core i7 - 7th gen Kaby Lake - and a great GPU, the …

Error handling with Status(Or)

I just read an article linked on Hacker News advocating the use of Either<L, R> to signal errors in functions. While I think this is a good start, in my experience Either is too general, the lack of standardizing of the error value makes error handling abstractions hard. How did that file function signal again that a file was not found?

What works a lot better in my experience is a more specialized type Status, with a standardized enum of error codes and a free form error message.

Here's an excerpt from the Status type [cached]we use at …

Tea

Tea has become my favorite beverage, bar none.

With flavors stretching from light and sweet white and yellow teas all the way to dark and earthy pu-erh, no other drink can match its variety of flavor.

Best enjoyed freshly brewed from whole leaves in a small pot, you need very little to start drinking great tea.

1. Some hot water, from a kettle or pot, doesn't matter.
2. A tea pot or infuser with lots of space for your tea to expand, see mine as an example:
3. Loose leaf tea!

Some of my favorite tea includes:

• [cached]Yunnan Dragon Pearl Black Tea …

Usability Testing on 10 Cents a Day

I just read Steve Krug's Don't Make Me Think and while I really liked the whole book, what especially stuck out was the chapter on usability testing as often as possible.

It doesn't need to be an expensive or time intensive process - just grab 3 people for 45 minutes each, pay them 50$, show them your website or app and ask them to use it while thinking aloud. Maybe give them a few simples tasks to do.

Repeat this process regularly - say once a month - and you should be able to catch a significant fraction of the usability problems on …

Standing Automation

I've had a standing desk at work for a long time, but I've always felt that I wasn't using it enough, that I still spent most of my timing sitting.

This week I finally decided to do something about it.

I bought a small sonar sensor (LV-MaxSonar-EZ1), hooked it up to an Arduino and added a little Python script to sample the sensor once a minute.

The sonar is mounted to my table and measures the distance to the floor, and with ~3 cm accuracy it's very easy to distinguish whether I'm sitting or standing.

Since the Sonar happily runs …

Big Problems

After having been sidetracked by AlphaGo for nearly a year, I finally had some solid thinking time for myself today. Mostly inspired by an [cached]interview with Yanis Varoufakis and a remark he made about why we need basic income, I started thinking about the big problems our world has and what I can do about them. These are from my perspective as a privileged first world citizen in the 1%, my aim is to identify the steps that are necessary to bring us to the next level as a species.

As an example - there are two ways you can …

Distractions

Reddit, Hacker News, Tumblr, Twitter, Imgur, Netflix, YouTube. The onslaught of pseudo information and conversation is relentless, it's easy to get lost in the comments. Feeling as if you are learning a something new all the time, a little gem in every post.

Somewhere along the way our natural curiosity and joy of learning has been hijacked and we waste away our lives reading and responding to useless chatter that seems useful and educating.

Every spare moment is filled by a quick glance to our smartphones, no time for thought and introspection left at all. Yes, that one post was …

Nutrition Information

Recently, I ran across a very useful website: [cached]Examine.com. They collect and summarize studies about many common nutrients and supplements. If you were wondering whether to take Vitamin D or what to think about creatine, this is the website to check.

A Book of Life

Inspired by Kaue's [cached]book about life, I've decided to collect my experiences and the various lessons I've learned in one place and write down generally applicable advice.

Without further ado, the Book of Life.

Why post it on this blog instead of using Google Docs or something similar?

• Full control of the platform. This is intended to be around as long as I'm alive.
• No problems with link rot. Thanks to the Pelican plugin I built, a copy of every page I link to is automatically saved to my blog so it can be viewed when the original is …