Month: September 2014

Using LCD HD44780 on Raspberry Pi – part 1: GPIO

lcd_16_tutorial_1

Right or left 🙂

 

So we can get weather data for our town and it would be good idea to display it somewhere. Time has come to dig into all kinds of LCDs. We will start from basic one – char LCD 20×4 based on HD44780.

 

(more…)

Advertisements

Using openweathermap api – part 2

In part 1 we learned how to use endpoint to read current weather and forecast in browser and now lets make a python package.

But just before lets make few points.

  • Our reader should work in background as thread,
  • Have ability to read data for few cities
  • Read data not in real time but with some frequency

Why ?
Simple, we don’t want to send requests to openweathermap server with each call. It would be lame. Lets imagine that main loop is reading and displaying weather each second (on nice 20×4 LCD). Doing each second a call to remote server would take ages (ok few ms but way to long 🙂 ). We are asking for data and we want it now. And what is also important data wont change so often. We don’t need to have a fresh packet from server.

(more…)