The Samsung Galaxy Note Edge can be extended by an inductive cover to load the battery. Samsung also sell a Flip Wallet cover for the Note Edge. The Flip Wallet cover have the ability to detect if it is closed or not to automatically switch the screen on for example. However there is no product which combine both features. In this blog entry I already described how to do it with a third party coil. Well in this blog entry I describe how make an inductive Flip Wallet Cover with the original Samsung wireless cover yourself. Before Android 5.1.1 it was sufficient to simply put the coil on the flip wallet cover to activate the flip wallet on/off function, but since the update this does not work anymore. Now you have to combine the three pin chip from the flip wallet cover to still use the on/off function. I describe how to do this further on.

In general pythons iterators are a nice way to iterate fast and source-code-clean over iterable. Sadly you can always only iterate over a single element. In general they are not really flexible (for example an iterator can not go back).

Sometimes you need to iterate not only with a single element but rather with a tuple of elements; therefore multiple previous and next elements to your current. There is always the problem what to do with your previous and next element at the borders or on which place of your tuple the iterator has to start and and end. Often calculations with the index are used, but this gets fast very ugly since you have maybe multiple border conditions and not every python iterable has also an index.

If you want to model object inheritance on a SQL Database you came along some problems. First of all inheritance is not implemented, so you need a workaround. There exists three common patterns which are called Single Table Inheritance, Class Table Inheritance and Concrete Table Inheritance. If the existence of a parent row makes no sense if no child row reference it (e.g. parent is abstract) you came into some problems with standard SQL settings to guarantee this invariant. Maybe you also want that a parent row can only be specialized by exactly one child, which is only with Foreign Key not possible. In this article I will face this two problems.

KeeChallenge is a KeePass plugin, which allows you to protect your password database with a second auth key. It implements a HMAC-SHA1 challenge-response where the key is saved on a Yubikey.

KeePass runs quite well under Linux with mono. However also the KeeChallenge plugin works under Mono, but you have to map some .dll to .so libraries, which I will describe here.

Requirements

Of course you need KeePass

sudo apt-get install keepass2

well you don't have to use this package, but I use the paths which the kepass2 package creates.

You need also the Yubico PPA:

sudo add-apt-repository ppa:yubico/stable
sudo apt-get update

after that you have to install the required packages: