The document discusses the use of Python for real-time control of stage lighting, addressing challenges faced in small venues, particularly with DMX protocols. It outlines the architecture of the existing and version 2 systems, incorporating various components such as USB DMX faders and the ZeroMQ protocol for messaging. Observations include insights on development methodology like 'rubber duck driven development' and the impact of unit tests on experimentation.

1. Spotlight on. Python
Python for realtime control
of stage lighting
Nic Cave-Lynch – Tymar Lighting

2. Spotlight on. Python

The problem

Current architecture

Version 2 architecture

DMX Engine

RDDD (Rubber Duck Driven Development)

Observations

3. The problem

Lighting bands, typically in small-ish venues

DMX: 40 updates/second, 200-500 channels

Moving lights (HTP/LTP)

Music usually new to me

4. 'Busking' in 4 dimensions

5. Enhance the music

6. Enhance the show

7. Current architecture
Input wing: serial asynchat DMX engine asynchat USB DMX
faders gathers HTP/LTP -> sends
generator
buttons wing input channel value DMX
USB (fcntl)
moving light Mimic
trackball capture
manager (wxPython)
trackball

8. Version 2 architecture
USB/ USB/
Input wing: serial/
ZeroMQ ZeroMQ DMX serial/
faders MIDI Input wing DMX Wifi DMX
generator
buttons controller struct engine struct generator
controller
trackballs
ZeroMQ ZeroMQ
protocol protocol
buffers buffers
Config UI / mimic

9. DMX Engine
 Engine()
– Holders for Valgens, Scenelets, Fixtures
– dispatches zmq messages from wing/UI
 Valgens know which Scenelets they drive
 Scenelet sends multiple of Valgen value to Fixture channels
 Fixture has channel for each aspect of the light
– output function eg calculate pan/tilt values from (x,y,z)
 Speed important:
– reduce lookups
– integer dict keys
– Valgen->Scenelet->Fixture single function call
– struct module

10. RDDD

Architecture took ages

Rubber Duck Driven Development

"make something that doesn't work"

11. Observations

Unit tests inhibit experimentation

Deciding to Open Source can be an inhibitor

Spoilt for choice in libraries/frameworks/etc.

Analysis paralysis

Surprising results in some performance areas

struct module

string/integer dict keys

I hate OpenOffice.org Impress 3.2: it's barely useable

12. For more live Python action
200 metres from dinner venue:
● Left out of Tulsi
● 20 metres to Guznee St
● Right up Ghuznee St
● One block up
● Straight over traffic lights
● Bodega is on the left