DMX Dongles

Posted on June 21, 2010 by admin

I have used two DMX Dongles for my Christmas lights:

  1. Enttec Open USB widget
  2. RPMs USB DMX Pro

The Enttec Open work great but was subject to a fair amount of abuse and kept blowing the RS-485 driver chip.

RPM got around the issue by including isolation between the USB and the DMX portion of circuitry.

Being based in Australia is always a challenge when sourcing components, especially for short run projects.  The link below is an Excel Spread sheet showing all but one component are available as an equivalent from  Bangkok based Futurlec.com.au.
My Futurlec.com BOM for RPM’s dongle Whilst the components selections work for me and I have not found any issue in its operation, you need to decide if the equivalent components are suitable for your application.

Continue reading →

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Weather proof DMX connectors

Posted on June 21, 2010 by admin

I hate using RJ45 connectors for DMX. They just don’t have sufficient mechanical strength. 3 pin ( I know soap and water in some quarters) and 5 pin Cannons are great but a bit pricing.

DMX wasn’t really planned for exterior use, I base this comment on the fact that no weather proof connectors are recommended.

So what to do?

Last season I cut a heap of weatherproof 3 pin male and female connectors off my LED light strings – they look ideal for the solution.

I figured if I keep the same pin out as a Cannon 3 pin connector as in the table below, everything should be sweet.

DMX Connections used by most Christmas Lights

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PortaFlood Show down

Posted on June 21, 2010 by admin

Now that I have both 500W and 150W Portaflood complete, it is time to add some performance data.

In the coming weeks I will be setting up a head to head test between PortaFlood 1 (500W), PortaFlood 2 (150W) and a 50W Dichroic halogen. The test will be in a dark room, measuring the maximum light at 1 meter using a uncalibrated light meter. That is where the “Reference” 50W globe comes in. This test will be a comparison one to a normal light you can buy for a light shop.

The distance of 1m will be maintained, but the light will be adjusted for maximum output. Both Voltage and current (Raw input power) will also be recorded.
Stay Tuned!

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Controller Design – 48ch DMX DC controller

Posted on June 20, 2010 by admin

I just love it when things all come together!  My mega tree will consist of 16 Red, Green and Blue LEDs Strings 4 meters long.  They were purchased towards the end of last years season from Big -W.  Members on DoItYourselfChristmas.com also helped out filling in missing strings, thanks to (Polar Bear and wjohn).  Each string operates at 36v.  Current limiting resistors have been placed in series with the LEDs. Below is the base plate, 4mm Alum (from Offcuts galore) with the 36V 350W SMPS and 3x DC Serial Solid State Relays.

Dc Serial SSRs

The heart of the tree’s light control will be my own DMX controller.  Expandable able to 64 channel, only 48 are being fitted for this year.  I may add White next year, we will just wait and see. As shown below, most of the repeatable work is done by using my DMX Mega BreakOut boards, leave new developments like LM2574 based Switch Mode Power Supplies.

64ch DMX LED Controller in Development

64ch DMX LED Controller in Development

The DMX controller will be fixed on top of the DC Serial SSRs using 18mm Stand-offs.  Details of the DMX Mega B/O board are here

The DMX controller is based on RPM’s of DoItYourSelfChristmas Grinch Dimmer.  The Main differences is the removal of the Zero-Cross detect / interrupt circuit and AC power supply.

I will also be adding Remote Device Management (RDM) for address management at some future stage.  For now the Start Address is programmed by transmitting the address in Channels 1 and 2 and pushing SW1 down on power up. Continue reading →

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LED PortaFlood 2

Posted on June 1, 2010 by admin

With the success of the original PortaFloods, I decided the review the design and make a new one for the 150W PortaFlood cases.  I can buy these for less than $10 a case.  S0me models also come with simple stand to act a work light.

17W of Bright White light

PortaFlood 2 has the following benefits:

  • Uses 10mm 1/2Watt multi-chip LEDs
  • Can be configured for 12, 24 or 36 Volt operation
  • Small and compact
  • Single Colour

PCBs will be available from my Webstore shortly.

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DMX Mega Break out PCB

Posted on May 20, 2010 by admin

Why Bother?

When prototyping new DMX controllers a lot of the time is spent wiring up similar connections all the time, like the USART for RS-485 driver and an ISP connector, to program the uC.  This is where my DMX Mega B/O board came to light.  I virtually got 25 of these for nothing.  One of the PCB suppliers offered 25 PCBs, up 100 sq cm for a fixed price.  By tagging them on to a production board, I was able to maximise the allocated area.

DMX Mega Break out module

DMX & AVR Mega88 breakout module

I choose to use completely leaded devices for the DMX Mega Breakout board so the components can be reused.
Basic Specification of DMX Mega B/O:

  • Uses AVR ATMega 48, 88,168
  • On-board DMX interface
  • By directional DMX ( essential for RDM)
  • On-board Ceramic resonator
  • On-board ISP connector
  • All unused I/F ports are available as individual pins including SCK, MISO and MOSI.

So how does it perform?

Other than stuffing the pin out for the ISP, so far it works well.  This minor stuff up is easily fixed with a custom ISP cable.

So if you don’t mind wiring a custom cable PCBs will be available from my Webstore shortly.  The next run will not have this problem.

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LED ProtaFlood

Posted on January 21, 2010 by admin

Way back in 2007 I was attending our local church.  The building is a two storey affair with top floor being reinforced concrete suspended slap.  Downstairs the youth group would meet and have a great time, being basically kid running riot.  they would also run mini concerts there.  recessed in the floor supports were PAR 38 floods with Zero protection.

One evening a light was busted and a couple of kids showered in glass.  That got me thinking about a more suitable light fitting  and after a bit of research , i stumbled on Big Clive’s RGB Flood lights. About the same time I noticed some Ebay sellers were offering phenomenal deals on bulk LEDs with great specs.

My LED Portafloods are an interpretation of Clive’s using what was the best single chip LEDs available at the time. The PCB are configured as RGB and operate on 24Vdc.

PCBs will be available from my Webstore shortly.

Finished LED PortaFlood

the finished product can be found in the gallery here

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