One of the most deeply rewarding aspects of programming is making the computer appear to do something; be it blinking an LED, printing “Hello, World!”, displaying a picture, or creating an animation, there’s something satisfying in making such output visible to the world.
Blinkenlights1 are the embedded world’s version of
"Hello, World!". If it’s possible to make an onboard LED blink on
and off, then you have probably got everything set up correctly (as demonstrated
in the earlier chapters of this book).
This activity might at first appear boring, since an LED’s purpose is either to be decorative or indicative of state. Crucially, familiarity with such an innocuous component provides an interesting route into MicroPython’s modus operandi. It demonstrates how MicroPython is both similar and very different to “normal” Python. This journey of discovery starts with the LED itself.
Light emitting diodes (LEDs) come in many colours and all work in the same way. From the perspective of physics, an electrical current of a suitable voltage is applied causing the occurrence of electroluminescence. In the case of an LED, a semiconductor material emits light in response to the electrical current. The colour of light is determined by the energy of the released photons. This, in turn, is determined by properties of the electroluminsecent semiconductor. Different semiconductor materials have different properties and thus produce different colours. The ...