“CD-sized device showing online time & weather data. Wirelessly powered and controlled, Using Arduino and ESP-01s. Easy to assemble.
1. Description of the device
The Rotating Display device comprises two primary units: a power supply unit and a display board (figure 1). Both are circular in design, with a diameter of 120mm, similar to the dimensions of a standard Compact Disk. The display board is rotated by a CD motor. Energy is wirelessly transmitted from the power supply unit to the display board, eliminating the need for wired connections.
The display board is equipped with two rows of LEDs, each containing 20 LEDs. This makes a total of 40 LEDs available for image representation. The LED operations are controlled by an Arduino Nano, while an ESP-01s microcontroller generates the display content. The ESP-01s maintains a Wi-Fi connection to the internet for this purpose.
This internet connection allows the device to retrieve the time from a time server, ensuring time accuracy. It also allows for the acquisition of weather data. Device operation is managed through a web interface (figure 2), accessible from any web browser. The interface allows users to manage login credentials, upload image files to the display, and control image and configuration files through a file manager.
2. Operating modes
When switched on, the device tries to connect to a known wifi. If no valid wifi credentials are found, the unit will be configured as wifi access point. In this mode, a computer or mobile device can be connected, directly (SSID: RD40, no password).
Once the wifi connection has been established, the unit will display its IP address on the home page of the device (figure 3). Enter this address in your web browser. This will load the web user interface and will allow you to configure your local wifi.
3. Mechanical design
The device consists of two assemblies: power supply and display. The power supply board is also the base plate, which can either be placed on a flat surface or hung on a wall. A standard CD motor is inserted through a recess in this board so that the CD tray above the board can accommodate the display assembly. The display board is fixed with two M2 screws. Furthermore, the base plate carries a potentiometer to control the motor speed as well as an on/off switch for the motor.”