WEB-SERVERНА ARDUINOС АВТОРИЗАЦИЕЙ И ГРАФИЧЕСКИМ ПРЕДСТАВЛЕНИЕМ ИНФОРМАЦИИ С ДАТЧИКОВ

Abstract

In the work on the basis of Arduino Mega and the W5100 controller, a web server is built for graphical display of remote client data obtained from temperature, pressure, humidity sensors. The server program is written in the Arduino IDE development environment. The Ethernet library for the W5100 has been updated, which for Arduino IDE ver. 1.0.3, 1.0.5-r2 caused the server to hang. The possibility of using the Dygraphs library for graphical visualization of data obtained with sensors is shown. Written scripts for drawing graphics for the projected web server. The data transfer rate from the Arduino web server for various network controllers ENC28J60, W5100, W5500 for the Arduino IDE programming environment and UIPEthernet, Ethernet, Ethernet2 libraries was analyzed. It is shown that with the lowest speed the data is transmitted by the web server with the ENC28J60 controller - 3.3Kb/s, with the largest controller W5500 - 23.4Kbytes/s. It is noted that these servers do not support multithreaded work. Therefore, they can not be used to create miniature universal web servers for processing multiple requests simultaneously. The server considered in the work can serve only one request from one remote client. The speed parameters of data transfer for the server on the ATmega328p microcontroller (Arduino UNO) with the network controller ENC28J60 are analyzed. The server program is implemented in C language in the AVR Studio programming environment. A high data transfer rate of 140Kb/s and a possibility of multithreading are noted. It is established that with simultaneous transmission of three files to different clients, the total transmission speed reaches 120-130Kb/s, and for each client 40-50Kb/s. It is shown that the use of such a server to solve the problem of graphical representation of data from sensors is difficult due to the complexity of transferring software to other microcontrollers and the limited library for working with a microSD card. The operation of the server developed here for three years has shown high reliability of its operation. The paper discusses the creation of a web server on the Arduino, which is a modernized HTTP basic authentication. The upgrade consists in the fact that for authorization a password is used from the list of passwords that is selected by the user on the basis of the key sent by the server. With each new login to the server, the previous password becomes invalid. Presents a practical example of a web server on Arduino Mega, Ethernet controllers: enc28j60 and w5500.