Monday, 18 September 2017

Putting some of my Python knowledge to a good use: a Reddit reading bot!

One of the perks of knowing a programming language is that you can build your own tools and applications. Depending on what you need, it may even be a fast process since you usually do not need to write production grade code and a detailed documentation (although it might still be helpful in the future).

I’ve got used to read news stuff on Reddit, however, it sometimes can be a bit time consuming since it tends to keep you wandering through every and each rabbit hole that pops up. This is fine if you are commuting and have just some spare time to spend on browsing the web but sometimes I just need a quick glance at what’s new and relevant to my interests.

In order to automate this search process, I’ve written a bot that takes as input a list of subreddits, a list of keywords and flags and browses each subreddit looking for the given keywords.

If a keyword is found inside either the body or in the title of a post which has been submitted in one of the selected subreddits, the post title and the links are either printed in the console or saved in a file (in this case the file name must be supplied when starting the search).

The bot is written using praw.

Sunday, 3 September 2017

Let Python do the job for you: AutoCAD drawings printing bot

Recently I’ve been getting familiar with AutoCAD and at the same time I’m trying to improve my Python skills. Odd mix, huh?!

While trying to improve my Python skills I thought I could exercise myself on automating boring tasks. I remembered that a few years ago I was given a boring job which involved printing a lot of drawings directly in PDF format from Autocad. I was too lazy to print the drawings one by one and I knew the process could be automated. At the time I put together a Python script that did the job fine, but it was a bit messy. I thought I could make an improved version.

When nice APIs are not available, such as in the case of AutoCAD (at least that was the case a few years ago, nowdays things may have changed), using Pyautogui may help in the task of automating boring tasks.

Saturday, 2 September 2017

How would you make a very simple and rotating magnetic field starting from a three phase power supply?

Recently I had a brilliant idea :D why not make a rotating magnetic field that can rotate a needle of a compass? (or any other magnetic needle for that matter).

Ok but the design must be very basic. One possible option would be the following:

Image 34

Simulation of the electric field of a three phase cable using FEMM

Finding analytical solutions to physical problems is always nice and rewarding, however it can be a bit of a pain when the geometry of the problem (just to mention one possible hustle) becomes more complex than just a sphere, a cylinder or any other basic shape.

If you think of a simple cable, with a copper core and a PVC insulation, calculating the electric field generated in the insulation layer using pen and paper may still be feasible, however, using FEMM greatly improves your life when doing calculations as an engineer, student, or “just” curious person.

This simple cable can be modelled using FEMM as follows

Image 20

The cable has a total diameter of 7 cm, with a first PVC insulation with a radius of 2.6 cm, a 0.05cm air gap and another PVC insulation layer.

Friday, 1 September 2017

Magnetics simulation with FEMM

FEMM stands for Finite Element Method Magnetics, and it is a nice software for solving magnetics and electrostatics problems.

I’ve known FEMM for at least a couple of years but I’ve never tried  it out and used it at its full power! Now the time has come to do that!

Image 1

In this post I’m going to present the results of the following simulations:

  1. A C shaped electromagnet (detailed results).
  2. The magnetic field of the rotor of a 4 poles synchronous machine (brief overview).