Controlling vacuum fluorescence displays with your PC

This page shows how vacuum fluorescence displays can be controlled by a serial interface on a PC.



VF displays can be found on many electronic flea markets. They are mainly used in cash register systems and vending machines. The advantages of this technology are a long lifetime and temperature resistance. Vacuum fluorescent displays are self-illuminating and can be made to have many great colors with color filters.

Picture: FC20X1SA display close-up

Picture: Close-up view of a display digit

Basically, the VFD consists of an airless tube. Heating wires send electrons across a grid to the segments. The segments themselves are coated with a luminescent layer, which is activated to glow by the impact of the electrons.

The displays used in cash registers and vending machines often have a small controller board. This controller can display characters that it receives via the serial interface.

Picture: Controller board on the backside

After I bought some displays on different electronic flea markets every year, I first created a DOS program then even Windows software and a Winamp plugin. These will be explained in more detail on the following sections of this page.

Controlling on Dos and Windows

As a program actually every simple terminal program works. I wrote a program under Q-Basic (for DOS) and Delphi (Windows), which can also be used to send control commands. Text as well as special characters can of course be output. I also developed a program for the Windows command prompt to output something e.g. by batch file.

DOS program

Picture: DOS program

Windows program

Picture: Windows program

Command line utility

Picture: Command line utility

The download link can be found at the end of the page.

Controlling using the Winamp plugin

Through an e-Mail I got the idea to program a Winamp Plugin for the FC20X1SA display. Currently the program supports all serial VFDs with FIPC8367 (or compatible) controller with 10-80 characters and the Siemens BA63 display.


Main window

Picture: Main window of the Winamp Plugin


Picture: Configuration of the Winamp Plugin


New in version 2.4.2

New in version 2.4 SE

New in version 2.4

New in version 2.3

New in version 2.2

New in version 2.1

Features of version 2.0

To install the plugin it is enough to copy the files into the Winamp\Plugins directory.

The download link can be found at the end of the page.

Different connection diagrams

The following part of the instructions should be read carefully. Each circuit has its advantages and disadvantages, the construction is differently complex.

Let's start first with the original circuit I designed for the FC20X1SA.

Picture: Circuit diagram for simple control

Picture: Construction with display

The main advantage of this circuit is that it is simple and can be built by beginners without any problems. In idle state the data pin of the display is pulled to +5V via the 10K resistor. As soon as a signal is applied to the port, the input is connected to ground via an optocoupler. The 5V supply voltage is generated by a fixed voltage regulator, which heats up the heat sink due to its more or less large losses depending on the input voltage. So the heat sink should be as large as possible.

The improvement of this circuit is a small extension to switch off the display via a relay if it is not needed. This saves power and protects the display.

Picture: Circuit diagram with relay

The extension should be self-explanatory. I would like to note that when the PC is booted, the DTR pin which is used to switch the display on, goes on and off several times, which is not very good for the display. Therefore there is a capacitor at the relay, which keeps the display active for some seconds after a short power-on.

The following circuit was designed for the KD2.1 display, but works also without problems with all other VFDs.

Picture: Circuit diagram with level shifter IC

Here the optocoupler was replaced by a level converter IC (MAX232). The circuit is relatively simple to build, and works reliably even at high baud rates.

The circuit was created in October 2006 during a new VFD tinkering action. By using a step-down switching regulator it is the most complicated, but also the most efficient circuit. The LM2575 produces hardly noticeable heat over a wide range of input voltages due to its high efficiency of about 80%.

Picture: Circuit diagram with level converter IC

What also bugged me was the clicking of the relay. Therefore a Logic Level Mosfet (Topfet) was installed here. The type BUK100-50GL can switch several amps and does not even need cooling in our case. The transistor in front of it inverts the signal, because there are 5 volts coming out of the MAX232 in idle state.

The circuit is so small that it can be integrated directly into the display housing of the KD2.1 without a voltage regulator!

Picture: PCB in the display housing
Picture: Shrinked circuit board

In picture 2 the PCB is shrinked with heat shrink tubing for isolation. Step down voltage regulator is external in the power supply.

Picture: Inductance
Picture: Switching regulator on breadboard

Picture 1: Inductivity on iron powder toroid. Photo 2: The external step down switching regulator.

An exception is the Siemens BA63 or FM20X2KB-100a. It has a 6 pin MINI-Din connector at the bottom and an integrated level converter, which simplifies the connection extremely.

Picture: BA63 simple circuit
Picture: BA63 with relay

The circuit on the right side can switch off the display when not in use.

Picture: BA63 pinout
Picture: BA63 socket

The picture above shows the pinout of the socket. Please remember the correct setting of the jumpers for 9600baud 8N1 on BA63: JP1 open, JP2 open, JP3 closed, JP4 open, JP5 open.

Infrared add-on (Winamp)

With this small add-on you can change tracks with an old infrared remote control. You can get the receiver at Reichelt Elektronik for less than one Euro.

Picture: Circuit infrared receiver
Picture: Infrared receiver in the cabinet

On this picture sensor and display are connected to one COM port. My software doesn't support a sensor yet, and two programs can't access one port at the same time. Therefore a small adapter is needed:

Picture: Schematic of the adapter
Picture: Design of the adapter

So the VFD plugin can send data to the display via COM1, and the IR plugin can read the sensor via COM2, and you save 2 cables.

Setting of the software: Install WinLIRC, start. Go to Configure, set COM2, enter a new configuration file at Config.

Picture: Configuration of WinLIRC

After that, the remote control must be programmed into the software. To do this, simply click on Learn. The software requires that a key is pressed 10 times to recognize the remote control. After that, each key can be programmed individually. Enter key name, press Enter. Press and hold the key on the remote control until a message appears. If everything is OK, save. Then the next key can be programmed. When all keys are programmed, simply enter no key name and press enter, confirm save.

Then copy the gen_ir.dll from the plugin zip file into the Winamp folder (Same as above for the VFD plugin.) In the Winamp plugin options select the IR plugin and click Configure.

Picture: Configuration of Winamp

With Add you can add a button, where in the upper field you can enter the name of the button. Below you can select the function of the button.

Other compatible displays

Picture: CU20026SCPB-T front side

Picture: CU20026SCPB-T back side

Picture: CU20026SCPB-T in operation

Picture: KD Rev 2.1 front side

Picture: KD Rev 2.1 back side

Picture: KD Rev 2.1 in operation

Picture: KD Rev 2.1 case

Picture: FM20X2KB front side

Picture: FM20X2KB back side

Picture: FM20X2KB in operation

Picture: FC20X2JA front side

Picture: FC20X2JA back side

Picture: FC20X2JA in operation

Picture: M204SD01AA front side

Picture: M204SD01AA back side

Picture: M204SD01AA in operation

Picture: 20M101DA1 front side

Picture: 20M101DA1 back side

Picture: 20M101DA1 in operation

Picture: FM20X2KB-100a front side

Picture: FM20X2KB-100a back side

Picture: BA63 front side

Picture: FIP20X2KA front side

Picture: FIP20X2KA back side

Picture: CU20045-T325A front side

Picture: CU20045-T325A back side

Picture: CU20045-T325A in operation

Picture: M202LD08A front side

Picture: M202LD08A back side

Picture: M202LD08A in operation

Picture: CU40026MCPB-S41A front side

Picture: CU40026MCPB-S41A back side

Picture: CU40026MCPB-S41A in operation

Displays from website visitors

FC20X1SA with Winamp Plugin (My display while coding in Delphi) and my KD Rev 2.1

Picture: FC20X1SA
Picture: Programming of the plugin

FC20X2JA-AB with Winamp Plugin (Built by Kai G. from Berlin, who brought me to the idea with the plugin.)

Picture: FC20X2JA-AB from Kai

FC20X1SA with Winamp Plugin (Built by Lutz H. from Uelzen)

Picture: FC20X1SA from Lutz

FM20X2KB with Winamp Plugin (Also built by Lutz H. from Uelzen)

Picture: FM20X2KB from Lutz

FC40X2EA with Winamp Plugin (Built by Matthias W.) The display is from a fire alarm system and has a red color filter screen!

Photo: FC40X2EA from Matthias

Siemens BA63 with Winamp Plugin (Built by Jens K. from Uelzen) With switching power supply, power saving mode and Golf III on/off switch!

Picture: BA63 from Jens
Picture: BA63 from Jens
Picture: BA63 from Jens
Picture: BA63 from Jens

Siemens BA63 with Winamp Plugin (Built by Walter H.)

Picture: BA63 from Walter

Siemens BA66 with Winamp plugin (Built by Wolfgang T.)

Picture: BA66 from Wolfgang

This nice greeting was sent to me by Jörg from Berlin! The display is a Siemens BA63.

Picture: BA63 from Jörg

Siemens BA63 with Winamp Plugin (Built by Tim K. from Itzehoe)

Picture: BA63 from Tim

ICD-2002 with Winamp Plugin (Built by Thomas S. from Leipzig)

Picture: BA63 from Thomas

Your display here? Just send me some photos, I'm looking forward to it!



Programs DOS / Windows

Winamp Plugin

Required software Infrared add-on Winamp

Last update: 02.08.2022