Linux Deploy is open source software for quick and easy installation of the operating system GNU/Linux on your Android device.

The application creates a disk image or a directory on a flash card or uses a partition, mounts it, and installs an OS distribution. Applications of the new system run in a chroot environment and work together with the Android platform. All changes made on the device are reversible, i.e. the application and components can be removed completely. Installation of a distribution is done by downloading files from official mirrors over the internet. The application can run better with superuser rights (root).

Some time ago, I found a curious device on the Internet — a keychain powered by a radioisotope of hydrogen (tritium). Its principle of operation is simple: a sealed cavity contains the isotope, and the inner part of the cavity is coated with a phosphor, which glows when exposed to electrons emitted as a result of beta decay of tritium. The half-life of tritium is 12 years, which ensures the continuous glow of the phosphor for many years.

I was inspired by this idea, and in 2012 I came up with the idea of making a keychain beacon that would glow and remain visible in the dark for a long time. You could use it for keys or for something else; I was simply interested in the idea. However, I decided not to use a radioactive element, but an electric circuit with an ordinary LED. The challenge was to make the LED glow for many years without replacing the battery, while keeping the keychain small.

It was one of my DIY projects, and I had a lot of fun working on it. I will share the details of each project in this post.