[EN] Using the DHT22/DHT11 Temperature and Humidity Sensor Module with ESP8266

This article uses the DHT22 and DHT11 temperature and humidity measurer modules with Python. They are sensor modules that operate using a single signal cable which will save the microcontroller’s port connection. In addition, MicroPython has a library prepared for DHT22 and DHT11 implementation, making it convenient, time-saving and reduce errors that may be caused by manual programming.

There are 3 examples in this article: code17-1 is a normal reading of values, but code17-2 is a loop to read again. By finding the highest and lowest values and display on the LCD module as shown in Figure 8 and example code17-3 showing the average value of temperature and humidity.

Figure 1 Result from code17-1

[EN] Binary Search Tree data structure programming with Python.

In the previous article, programming to implement queue-based data structures was introduced. In this article, we introduce programming to manage another type of data structure which has different storage and management methods called BST tree or Binary Search Tree, as shown in Figure 1, which is a structure that can be applied to data collection with attributes in which the data in the left branch is less than itself and the right branch is greater than itself or the opposite, i.e. the left branch has a greater value and the right branch is less. It enables searching for data in cases where the tree is balanced on the left and right in the BST structure, saving half the time or number of search times per round of available data, e.g. 100 data sets in the first round if it is not the information you are looking for will be left with a choice to find from the left or right branches which the selection causes the information of the other side is not considered or cut off approximately half. However, if the Binary Search Tree is out of balance, the search speed is not much different from the sequential search.

In this article, we use Python that works on either a Python 3 or MicroPython interpreter to store the data, adding information ,searching for information as an example of further development.

BST : Binary Search Tree
Figure 1 BST

[TH] การใช้ GPS ใน Unity3D

จากบทความ Unity3D ครั้งที่แล้วได้กล่าวถึงฟีเจอร์บางส่วนในโปรแกรม ในบทความนี้จึงขอกล่าวฟีเจอร์หนึ่งที่น่าสนใจ คือการใช้งาน GPS ใน Unity3D โดยเฉพาะผู้เริ่มต้นใหม่ เนื่องจากในโปรแกรมมีการใช้งาน GPS ที่ค่อนข้างง่าย

[EN] Control movement from a joystick via WiFi with MicroPython.

This article is based on the article programming a client/server for a weather station over a wireless network or WiFi to modify from reading data from sensors to joystick shield (Arduino Joystick Shield) so that it has become a wireless game controller using MicroPython and an ESP32 microcontroller as shown in Figure 1. It is possible to control the movement of objects in the display via a ST7735 TFT screen connected to another ESP32. It will be found that the Python implementation of MicroPython is applicable in this example. And with an easy-to-write language and code that can be modified without recompiling and uploading, it’s easy to write prototype code for further development at a higher speed.

Control movement from a joystick via WiFi
(Figure. 1 Our board)

[EN] The dCore-espWST

This article recommends using the esp8266 to read temperature and humidity from the DHT11 sensor, the voltage from the LDR sensor, received from the switch, and display via OLED with MicroPython’s Python language, this feature is the dCore-espWST board we are using (Which in the previous article we used the dCore-esp32WST with the same design, but using esp32, but the program code can still be used with the model board) and is a board for use in teaching IoT subjects. The prototype structure of the board is as shown in Figure 1, which is normally used with a battery power supply unit with a solar panel charging circuit.

(Figure. 1 dCore-espWSTprototype)

[EN] Temperature and humidity indicator bar

This article is an example program for cases where you want to display the temperature and humidity bar as shown in Figure 1 with MicroPython and esp32 board with OLED. How to write? The equipment in this experiment used DHT22 as a humidity and temperature measurement device. The board is connected to the I2C bus to communicate with the OLED via pins GPIO4 and GPIO5 for SCL and SDA respectively. At the same time, the signal pin of DHT22 is connected to pin GPIO15 for communication between the sensor and the microcontroller.

(Figure. 1 Example output of temperature and humidity bar display)

[EN] Queue Data Structure

This article introduces the use of the list class in Micropython as a queue data structure with a limited number of members. It works according to the FIFO (First-In-First-Out) principle, which can be applied in a variety of applications, such as being used as a storage, and when the data is full but we need to insert new data, the old data must be pop out. The example in this article uses the dCore-miniML board (Figure 1) to read the temperature of the chip and store it in a Queue structure and display it in a bar graph and Micropython implemented firmware version 1.16 (2021-06-23) for the ESP Module (SPIRAM).

(Figure. 1 An example of drawing a graph with data stored in a queued data structure)

[EN] ESP8266 WebServer

This article is an experiment to make the esp8266 microcontroller a web server to display temperature and humidity values from a DHT11 sensor using the Adafruit library as shown in Figure 1. When the microcontroller is run in SoftAP mode, the client or user connects to WiFi after using the browser to access 192.168.4.1 which is the IP of esp8266.

(Figure. 1 Our equipment)