Coding

Ever since I advanced beyond the “hello worlds” of Java, I had never stopped coding. This section is for documenting code usages that I had employed while solving the technological problems that I had encountered.

How to write a C# program to communicate with an ESP32 development board via Bluetooth Serial

Coupled with Bluetooth Serial and GPIO pins, ESP32 can augment a Windows machine with the ability to read from sensors.

So with an ESP32 development board, you can turn your old Windows machine into an IOT gateway that can sense its operating environment.

Given these points, let us look at how we can write a C# program to communicate with an ESP32 development board via Bluetooth Serial.

How to use C# to read sensor data from Arduino or ESPx via serial connection

When you have an old Windows machine, you can convert it into an IOT gateway.

So how can we read sensor data with our windows machine? Since our windows machine probably do not have GPIO pins, we can read sensor data via an intermediary device.

For example, we can first attach an Arduino Uno or ESP32 development board as the intermediary device to our windows machine via USB. Given that connection, the intermediary device will read the sensor data and send those values via serial. On our Windows machine, we can then run a program to read those values from serial.

So how can we read sensor data from Arduino or ESPx via serial connection on our Windows machine? Since C# is a programming language for creating windows application, we can use C# to read those data from serial.

How to create an API endpoint that generates a QR Code image, with Python 3 Flask-RESTPlus and python-qrcode

When you have an API endpoint that generates a QR Code image, another device with a QR Code scanner will be able to get the encoded value to perform some action. For example, WhatsApp web generates a QR Code image that encodes a code for WhatsApp app to sign in the user.

So how can you create an API endpoint that generates a QR Code image? With this in mind, let’s look at how we can do so with Python 3 Flask-RESTPlus and python-qrcode.

How to detect keyboard presses made to the browser screen with JavaScript

When you are building a browser-based game, being able to track key presses is helpful.

For this purpose, you can register a JavaScript function that gets called when the browser detects a key is being pressed.

After the browser detects a key press, it will send information about the key to your function.

When your function is able to get the key that is pressed, it can then use this information to update the game state.

In this post, let’s look at how we can detect keyboard presses made to the browser screen with JavaScript.

How to control a SG90 servo motor with the ESP8266 NodeMCU LUA Development Board

When you are looking to operate remote-controlled or radio-controlled toy cars, robots and airplanes, you will need to use servo motors.

Since the ESP8266 NodeMCU LUA Development Board is cost efficient for IOT solutions, it can be used for controlling servo motors.

So how can we control a servo motor with the ESP8266 NodeMCU LUA Development Board?

This post discusses how we can control the SG90 servo motor, with the ESP8266 NodeMCU LUA Development Board.

Getting the environment variables supplied to your Cloud Foundry application with Python 3 Flask

When I was trying to build a Python 3 Flask application on Cloud Foundry, I wanted to quickly check the environment variables that Cloud Foundry will supply to my application.

As a result of that, I created a Python 3 Flask application that will probe the environment variables that it receives from Cloud Foundry.

This post lists the files that constitute that Python 3 Flask application.