EL Displays

My Nixie Addiction

EL Displays

A fellow enthusiast introduced me to these Russian Electroluminescent (EL) displays that are currently available on eBay.

I decided to have a go at driving them using Smart Socket technology (detailed elsewhere on this site).

This is a record of progress thus far (or at least what I have got around to writing up thus far!)

A fellow member of the Smart Sockets group has posted an interesting video about these displays:

Introduction to EL Displays

The following link leads to a lot of helpful information on these displays.

More information on EL Displays

I have designed a prototype Smart Socket board to drive these displays. The Board will handle all the necessary switching of the 200V 500Hz AC supply which is required to drive these things and will operate as a traditional ‘Smart Socket’ which means that it will display the segments required to form the desired characters in response to simple ASCII command strings sent from any micro that can send serial data at 9600bd at 5V logic levels.

The Smart Socket fits on the rear of the display and multiple displays/boards can be daisy chained together to form a larger display device.

A suitable 200V/500Hz AC source will be required so for testing purposes I am using a relatively cheap/simple EL Wire power adapter.

An EL Display showing all segments illuminated.

This is V1.0 of the EL Smart Socket.  A PIC16F690  processes the ASCII commands and then controls the Opto Triacs as required.

The Opto triac controls another triac which in turn switches the HV/AC supply.

Each display has a common connection and then one connection per segment.

The PIC will be programmed to display the basic numbers 0-9 though interestingly, because of the segments available, it would acutally be possible to display 10-19 as well as any other character that can be defined from the 8 segments available.

For a 6 digit device, to display ‘115801’ the serial command would be ‘$B7M115801’ where ‘$B7’ is the required preamble, ‘M’ says that what follows is a series of characters to display and ‘115801’ are the actual characters to display.

Various other commands are availeble to control transition effects and speeds as well as allow the definition of user defined characters.

The Smart Socket concept is traditionally used on devices with more segments such as the Burroughs B-7971 or Telefunken ZM1350 so the code is set up to deal with more segments. These can be ignored for the purposes of this project.