Hands-on Tutorials

Estimate distance and position of solid objects using multiple low-cost ultrasound sensors.

Sensor Array based on the broadly available HC-SR04 sensor. Photo by the author

In this article we are going to build from scratch a sonar array based on the cheap and popular HC-SR04 sensor. We will use an Arduino microcontroller to drive and read the sensors and to communicate to a host computer using serial communication. Here is the working code for the full project however I recommend you to follow the steps in the article to understand how it works and to customize it for your needs.

The HC-SR04 is a very popular ultrasound sensor usually used in hobby electronics to build cheap distance sensors for obstacle avoidance or object detection. …

Photo by Julie Fader on Unsplash

In these article series we will learn how to setup a simple payment workflow with Django using the Stripe payment platform. We will use the Stripe dashboard to manage products and configure our pricing model and taxes so we don’t need to worry about handling this in our app.

The full code of this project is here however I recommend you to follow the step-by-step instructions instead of copying the whole project in your local environment.

We will keep track as well of…

Photo by Gautier Salles on Unsplash

In this article series I want to help total beginners in Django to setup real-world apps with minimal knowledge of the platform to be dangerous and build awesome modern web apps.

In this first article we will cover the basic of setting the up the development environment and installing Django with the default admin panel. No previous knowledge of Python is required for this article.

What you will learn today:

  • Create and work with a Python virtual environment.
  • Install project dependencies
  • Setup a Django project and database
  • Setup the Admin user and panel

Installing dependencies

Open your favorite terminal, create a project…

Total beginner’s step by step guide on how to sell digital content as a non-fungible tokens or NFTs in the Blockchain

Image by Beeple (Mike Winkelmann)

NFT is the latest hype that seems everybody is selling or buying. It stands for non-fungible token in the cryptocurrency world, the non-fungible part of the definition can be confusing but it just denotes that it holds something unique you can’t exchange to another one of the same value. For example, one Bitcoin token is a fungible item because you could exchange it for another Bitcoin, and it doesn’t matter which specific Bitcoin tokens you have in your wallet, they all have the same value at any moment of time. …

Unleash the power of your Raspberry Pi with a broad ecosystem of apps and packages

Photo by Gary Rockett on Unsplash

There are many reasons why you would want to put Ubuntu in your Raspberry Pi instead of the official Raspbian OS. In my case I usually use Raspberry Pi as a low-powered portable computer for small robotics and AI projects. Many drivers, packages and dependencies are only fully supported in Ubuntu (as ROS2 🤖 or OpenCV 👀) but not in Raspbian.

In this article I want to go through the different common steps you will need to successfully setup a Raspberry Pi 4 or Raspberry Pi 3 with the latest versions of Ubuntu for the ARM 64-bits architecture, currently Ubuntu…

Photo by Donald Giannatti on Unsplash

This is our last article of the series, we have learnt so far how to code a simple web store in Django and accept payments with Stripe. Now we are going to learn how to handle the post-payment actions listening to async events from Stripe with a webhook.

The full code of this project is here however I recommend you to follow the step-by-step instructions instead of copying the whole project in your local environment.

What…

Photo by Anne Preble on Unsplash

In this third part of our article series we will learn how to code the secure session checkout creator for Stripe.

The full code of this project is here however I recommend you to follow the step-by-step instructions instead of copying the whole project in your local environment.

What we will learn today:

  • Register new products and prices in Stripe
  • Code the checkout session creator with Stripe

Register new products in Stripe

In our previous article we made possible for the…

Part 2

Photo by Iwona Castiello d'Antonio on Unsplash

In the previous article we learnt how to setup our project and register new customers in Stripe with signals using an isolated app inside our project. Today we will continue our journey building a robust and simple way to accept payments with Stripe.

The full code of this project is here however I recommend you to follow the step-by-step instructions instead of copying the whole project in your local environment.

What will you learn today:

  • Build…

Photo of Novel Coronavirus by CDC

Disclaimer: I don’t have a formal education in health science or biology and I don’t understand in detail how human virus infections work, migrate or transmit between humans or animals. Thus, I don’t pretend to build a complex model to estimate the current 2019-nCov outbreak and future outcomes. My goal is to explain the current reported data available from official sources using simple statistical methods and to have some baseline to understand the current situation.

In the recent days I have been surprised by the disparity of the reports about the Novel Coronavirus (officially named 2019-nCov). While some sources claim…

Alberto Naranjo

Software Engineering. Robots. Sometimes I write

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