This is a prototype that implements the concept of a physical progress bar. It is based on a motorized studio fader that is connected to a microcontroller. The controller provides routines for a bidirectional data flow. This means that a host can send a value to the device. The fader is then automaticaly driven to that position. Vice versa if the lever is moved manually, the value is sent to the host.

It was published in the Elektor magazine for hobby and professional electronics in the January 2010 issue. The Elektor is read in 50 countries around the world and has a print run of 120000 (information according to the official Elektor media information). I wrote the article and they took a photo of my prototype for the magazine. As I have been reading the Elektor for a decade I am very happy that one of my projects has now been published :-). The project is refered to in the Elektor as project 090531. The software for this project (AVR and VisualBasic code) can be downloaded here.

The example prototype is a control device for Winamp MP3 player that connects to the PC via a USB port. The red lever represents the current position in a track and moves along with the song. If the lever is moved, Winamp jumps to the corresponding position of the song. Additionally, four buttons and an LCD display were implemented. The buttons provide play, stop, next and previous functionality.
In the LCD the songtitle is scrolled together with the time, date, CPU workload in % and RAM usage in %. A video of the system in action on Youtube: The system also consists of a small utility that runs in the Windows taskbar. The program interfaces both Winamp and the USB device and is programed in Visual Basic. When an error occurs (Winamp not running or device not connected) the green Winamp icon turns red. If only Winamo is not running, the time and date are displayed on the LCD. If the FTDI device driver is modified the utility identifies as Winamp Control "WinCon". It is a virtual comport. But the Windows drivers can also be used. It is just neccassary to programm the "Device Name" of the FT232RL to "Wincon". This is the Elektor PCB. There is a kit available at the Elektor page with all the parts and PCB.