Bluetooth & Audio

I have been working on device based on the BC127 bluetooth module. The idea is to and from stream audio over bluetooth to this receiver. The user wears this pack a bit like an IEM… in fact the idea is to use it with IEM style earphones. The transmitter connects to a unit that combines coms traffic from hardwired coms loop and radio, and has an input for a program mix. The transmitter is proving more difficult. The beltpack works for the moment… It is has a lithium poly battery, USB to charge it, a couple of buttons to engage microphone on radio or hardwire, and global volume. The mix between channels is made at the as yet unstarted base station.

New Workshop!

Over the Autumn I have been moving into a new workshop with more space, CNC and electronics facilities, this will speed up delivery of DMX testers and creation of new prototypes. There might even be space for a lightbox or too.


img_3538This Chandelier was created by designers Rob Howell and Hugh Vanstone for a refresh of the Foyer lighting in the Old Vic Theatre in London. It is made up of twenty strands of yellow construction site festoon tangled and dripping from a meter square rebar cage suspended ten meters above the foyer.

PLP Pracs provided the control, fittings and installation of the 220 LED Squirrel cage lamps in custom festoon harnesses.

Control allows the chandelier to gently pulse, be static at various intensities or be programmed to suit the current performance. It provides a warm glow for the audience to rise up to each level of the auditorium by.

Pulse to DMX

I was approached by WhiteLight Ltd to create a device that allowed guests to interact with a light installation in an unusual way – via their pulse. The brief was something that would allow each person to control a 280m long installation of RGBW uplighters in a tunnel using their heart rate. I made this Pulse to DMX sensor using a ‘Pulse Sensor Amped’ from Pimoroni, it outputs an analog voltage when a finger is placed over the pad. I chose this because electrically isolated from the user, so I didn’t have to worry too much about other forms of electrical isolation from the rest of the system that the ECG type of sensors need. The sensor is connected to a unit that analyses the waveform, and converts into 5 DMX channels, BPM, Pulse trigger, Pulse present (or enable), raw data, and a variable frequency sine wave.

The installation was actually controlled by a GrandMA console, and the Pulse DMX sensor was used as an input to trigger a one-shot effect, and a contact closure for sound, to trigger a heart beat type sound.

Miniature Strobe / Flashing Hands

For The Ruling Class at the Trafalgar Studios I made some “Electric Hands” using some tiny Lumileds and a modified version of my wireless dimmer project. The result is a really bright and tiny strobe. The video shows one of the prototype units. The final version were mounted to two elasticated wrist straps and was used in part of a programmed sequence.

Ultra Bright LEDs …..Wireless AND Battery AND small

I’m looking for a product that does wireless dimming AND has an on board battery. If my phone has a huge LiPo battery in it ( with a ability to charge easily), has wireless communication, can drive a ultra bright LED and can fit in my pocket… then why can’t my wireless dimmer.

I have been experimenting with Phillips Lumileds Luxeon – LXCL Series for a project. These are designed to fit into your smartphone to provide a torch and/or a flash for the camera. They are mega small (2.04×1.64mm) and can handle a huge forward current in short bursts. This makes them massively bright. The design challenge here is drive the things at the right current and voltage (using a handy IC) and to make it all fit in a small bodypack so it can be worn.


This project is partly an upgrade to my wireless dimmer stuff, to allow a greater current capacity. I have recently needed to do simple logic things with LEDs, like pressing a button to turn a LED on, and then have DMX override etc. This board has DMX capacity, two local pots for control of any parameter, like intensity and rate of a flicker for example and 5 contact inputs. The idea was to make something flexible that I can repurpose for anything that comes up without having to bodge one of my original radio boards which I currently do every time I need something a bit odd.

Switch 6… update

I have been working on finishing the Switch6 project. It is 6 channel relay board, with DMX input. The board in the photo does not have the tab top relays there will be in the final version. this will allow 16A switching per channel.

The software is now finished, its really simple. Dip switches to set the DMX address, with one switch to set the switch on level, either 5% or 50% (DMX 127)

I wanted to make something like this, to perhaps use with a socca outlet to hang out the back of an AVO rack or similar.

ArtTubes v09- upgraded to 16 Universes

ArtNet Tubes v08 makes an appearance at Electric Daisy Carnival festival, upgraded to control 16 universes DMX mapped to MiTRIX LED Display on portals on the stage. This software takes an ArtNet input and maps each group of 3 channels to a pixel on video output. The size of the pixel area controlled by each group of RGB channels can be adjusted to give some mapping flexibility. It ran on a pair of fairly standard Macbook Pros, one as a redundant backup.


The prototype of a flame effect fire with water mist for Marcushall Props – now on stage in the Noel Coward Theatre as part of Shakespeare in Love.


Now with 4 single channel programmable dimmer module to make a fading/flicker effect. I designed these modules for a friend who wanted single channel dimmer control via serial. In this case I just programmed each one to do a random chase.

How the STATE DMX testers are made.

I have been asked by a few people how it works, so here it is. It is quite an involved process although the machines do the hard graft. It is of course possible to get someone else to assemble the circuit boards and make the enclosures, but that is neither fun, nor cost effective at this stage.


I designed the PCB using CadSoft EAGLE, I send the files away to be turned into a board.

The enclosure is designed in CAD, and then I use Lazycam & Mach3 to convert the drawings into GCODE ( a set of really simple machine instructions that tell the cutting and engraving tools where to go and what to do).

The software on the unit is written in C++, and that is probably the subject of another post.  I get ideas from time to time about how the interface could be developed or made easier to use from the people around me at work.

The PCBs arrive and are populated with components. I do this by hand, due to the low volume. Some of the components are are very small  (<1mm ) so some concentration and a magnifying glass is needed. I use solder paste and a small tipped soldering iron and work on a number of boards at once, placing each part across the whole batch.

First stage of testing is completed at this to check voltages and battery charging operation are OK.

The encoder side panels go into the CNC machine to be cut. I do these first so that the assembled PCBs can be then attached to them while other things are happening, like adding the red switch caps and the OLED screen.

The XLR backplane is soldered up, this has a little bit of ribbon cable that needs a crimp header crimping onto it that connects it to the main board

The XLR end panels go in for CNC milling. I usually do these in batches as it is quicker to set the machine up once and then just keep feeding it material.

Each panel takes about 5 mins to cut.  The XLRs are then screwed into the panel.

The polycarbonate windows are milled in the same machine. Due to the thickness of the material they are done one at a time, any more the warping caused by the clamps mean that the final size of window is not accurate enough.

The main body of the tester is now milled. All the square holes are cut first and the 1mm recess for the window. Then it is time to change for the engraving tool and the engraving is done.

While the machine is working hard cutting holes the PCBs go over to have their processor fitted and flashed with software. At this stage I modify the line in the code that sets the customers name on the splash screen. Spelling of the name is not my strong point, so this needs to be checked at least twice!

The windows are snapped into the main body and the whole unit is assembled, adding the LiPo battery and encoder knob.


Once the unit is totally assembled I then walk it through some function tests, checking that all the buttons move ok and do what they are supposed to do.  I then check is the unit outputs DMX within spec, and receives DMX ok.  MIDI is checked against an MSC output from Qlab. The last step is to verify that LTC functions correctly by plugging the unit into a timecode generator. 

The last stage is to print the manual, and then check everything into the postbag, making sure not to forget the little purple bag or LTC/MIDI adaptor.




Switch6 is a simple DMX relay card. Unlike the DMX relay cards that you can readily buy its relays are rated to 16A per channel, and the current is kept of the PCB through use of tab top relays. I’m going to build some of these cards into enclosures with socca out, to use as a proper relay backfeed for a AVO dimmer. You could use it for anything else that needs switching. It has a standard piano dipswitch for address setting.

STATE: Back in Black

STATE Dmx Testers are back in stock, in black. If you want one in silver that is also ok, but the black looks cool.
I am calling these units R3. They are the same as the ones that are currently out there except for the black finish. Perhaps more interestingly, they have the ability to record DMX Snapshots. So if you plug it into you console you can save a look (or 200 looks) and then play them back at a later date. This might be useful as a backup for example, or for a situation where you need to flash in the setup of a load of standalone fixtures. You could even use it (or loads of them) as little lighting systems for an event. If you were feeling keen, a number of snap shots could be recorded as a test setup for moving lights. The states are saved in non volatile memory, so will be retained if you turn the unit off, or run it completely out of batteries.

Once you have loaded back a memory the levels recorded can be adjusted live. There is currently no fancy fade times etc between memories, it simply records all DMX channels incoming and saves them in a memory marked 0 to 200. There is a bit of space for more memories but I am saving that for future software revisions.

Buy one here

ETC EOS Moving light focus Photos….

A few years ago I wrote a bit of software to automate taking of focus photos using a strand500 and MIDI. It is time for an update, I have been sitting in the theatre writing this in gaps between being needed smashing keys on the typewriter. This time it works with ETC desks using the remote client connection and dongle, and takes photos using a Cannon camera. The application renames the files downloaded to the computer by Canon’s own software, with the channel and preset that it has driven the light too.

The presets photos that need to be taken are saved in a .CSV file in the application folder, a line for each.

This should speed up the process of documenting my moving light focus in a weeks time. Still to do is an parser to automatically generate the ‘used preset’ list, but that is for another day.

You can see me doing a terrible demonstration here.

CurrentBun RDM

I have just sent for fabrication some prototype PCBs for a new CurrentBun system. The idea is to report via RDM:
• Current RMS across three phases
• Voltage RMS across three phases
• Frequency, P.F.
• Local temperature to the unit

This first spin of the board has an 2500V isolated DMX port for RDM communication, a local display and interface for settings and readings and a real time clock / SD card socket so that readings can be logged locally.

The idea behind this unit is that you could use it to report current draw on a system remotely i.e. at your dimmers/distro from your desk, using the standard DMX infrastructure that you already have in place.

Lots of software to write!

at the place where three footpaths meet, there is MIDI

This month I have working on a number of different devices that send simple MIDI messages from simple inputs. Wireless buttons to midi notes, simple switch to configurable MSC message etc. Why MIDI ?, it seems to still be the easiest way to get new human input into an existing product, or the control product of choice. Sound, video and lighting people can all agree on it. Perfect.


Exhibit has a wide ranging remit, essentially inspired by a need for an easy way to interface lighting, sound video etc in a museum or gallery, or interactive performance. This project was inspired by the 5sq XGO I used for the War Horse Exhibition, and also incorporates the features of the MIDI to DMX bridge. I have designed Exhibit to be as flexible as possible:

• 84 contact closure inputs (expandable) for switches etc.
• MIDI out – programmable Notes, Controllers, SysEx, MSC etc
• DMX 512 in and out – control lights, trigger consoles, media servers.
• Analogue sensor cards can be fitted to allow environmental sensing etc.
• LCD display shows status of inputs and outputs.
• Internal logic – The unit can be programmed to do useful things eg lockout inputs until an event, AND, OR, NOT sort of operations of inputs can simplify programming of installation.

• Inputs are via RJ45 connectors, allowing use of cheap network cable for large installations
• ExhibitTerminal is a RJ45 to terminal block PCB – for easy connection of switches to network cable.
• Internal PSU for easy and secure installation.