Modell of the stage of the Thalia-Theater - Thalia Backstage.

Model of the stage of the Thalia-Theatre in scale 1:25:

You can see the 4 boxes on each side of the stage of which the upper ones are used for lighting. The ground is layed out with white paper by me, so that the lights can be seen. This is normaly not done on a theatre-stage because it is not interesting to see the light on the ground, but to see the light on the actor. Some times this is heavy to work if the producer only want to see the head or the hands of a person, or the light has to be cut exactly on the upper side of a wall. Lighting positions in front of the stage: 3 lights in the upper left box 3 lights in the upper right box On the left side of the stage you can see the light from the left tower.

On the left side of the stage you can see the light from the left tower.

The theatre from the back without lights on

Lighting positions on stage (from the left to the right): 4 lights in the upper right gallery (left side of the picture) 3 lights on the right tower 5 lights on the upper middle galery 3 lights on the left tower 5 lights in the upper left gallery (right side of the pic.) 2 light on the same dimmer as backlight on backstage (can not be seen here)

The theatre backstage with lights on

The lights that can be seen here are for 3-4VA/12V as they are used as signal lights in cars. They have a lense in front. The model has 24 of such lights.

The theatre backstage with the dimmer-rack

On the picture you can see the 19" rack of the dimmer. Over it you can see the model of the theatre and you can also see the three connector for the 24 load-outputs. The little vertical bar on the left sied of the picture is the back-side of the theatre that has been removed to have a view inside.

This is the dimmer-rack of the theatre model (24x12V)

Inside the 19" rack from left to right: 1 x Power-supply 5V,+12V,-12V (bought) 1 x DMX-receiver 1 x DA-Converter 12 x 8Bit (0..-10V) 2 x digital phase controller (6 channels with 8Bit on each card) 2 x analog phase controller (6 chanels each card) 1 x zero cross detection for all cards 4 x Triac boards (optocoupled) each board 6 x 8 Ampere

The System Bus

The system is build around a backplane that contains the system bus. It is made up of the power supply, the 10 bus address bus, the 8 bit data bus, some control signals and some per slot io lines.

I do not have an image of the system, bus now. One day I will remove it from the rack to make one

The Digital Analog converter

The DAC board contains three 4 channel 8 bit digital analog converters that are accessed thru the control bus and provide 0V to -10V to the io lines. The Board can be addressed on a 16 byte aligned address.

The Digital Phase Dimmer

The digital dimmer board hosts 6 channels of digital dimmer controllers with 8 bit each. Each dimmer is made up of an 8 bit data latch (74HC574) and a down counter with an async reload (40103). The 50x256 Hz clock is provided by another board, that also hosts the zero cross detection. The GAL20V8 is used for address decoding and selecting the right data latch.

The Analog Dimmer

The analog dimmer boards each hosts 6 channels, each build up of a ramp, synced by the zero crossing, and a comparator.

The Triac Board

The triac board contains 6 triacs with the needed peripherials around them. The control path of the triacs have an optical isolation.

The DMX512 Receiver

The DMX512 receiver is not part of the final year work. I have build it up later, to be able to use the theatre model with a desk capable of producing dmx512. It has a DMX512 input and dip switches for selecting the start address.

It is made up of an 8031 with an EPROM and a 75176 RS485 receiver chip.If contains a fixed configuration with two DPAS and two DAC cards.

The original schematics

The original schematics and layouts have been created with an old DOS version od PADS. As I made them at the university and do not have PADS at home, I am not able to export or plot the original schematics and layouts. One day I may be able to get my hands on such an old version of PADS to do so. In the meantime I recreated the schematics with KiCad off of my head and what I did not remember I took from the existing boards. Once I have them together and checked, I will put them here.

Screenshot of the Control Software

The features are:

• Main Menu (top) can be configured.
• Quick command bar (bottom) can be configured (same syntax as main menu).
• Channel window in the top right corner with Master and Offset Fader.
• Five Groups with selectable channels.
• A cue editor
• A program editor

The software is written in C for MS-DOS. I started with Turbo-C and soon changed to gcc.