DMX Load

Posted on November 26, 2010 by admin

A fair number of controllers have DMX loads built in. I don’t use them. I am always worried id leave a load jumpered when I extend the DMX line further out.
Either way you need to get to remember to add a DMX load at the end of each run.

With the rise of more RJ 45 being used for DMX wiring, especially in this hobby, I thought it was time to make a couple of RJ45 loads. They are a cinch to make and give immediate confirmation there the load is in place. Also as the load is plugged into the “Out”, you can’t get any loads left jumpered mid-stream.

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TOT – Reflow Oven

Posted on September 20, 2010 by admin

I have a small 7litre oven that works a treat for Reflow of small boards.

I recently upgraded to a 20 litre oven with two element top and bottom.  Rated at 1500Watts, there is able power to heat the area.

Front Shot of 20litre Oven

Having run the oven a couple of times manually I have concluded the following:

  1. The Temperature setting is a waste of time.  it appears to be a simple bi metal switch and not a thermostat.
  2. The top needs some form of Insulation as the top lid gets really really hot.
  3. The Rack inside the oven is not attached to the door – bonus as far  as I am concerned.
  4. I need to come up with some form of automated venting to cool the boards down.
  5. I may be able to fit another shelf and increase the throughput ( I am looking for some AL material with a 5mm grid of 5mm holes).

Simple Layout

An interesting note: the top elements are connected in series, as are the bottom elements. This is quite nifty as there is no need for a neutral return.

For now I will leave the oven as is that start the Controller.

I have been playing around with the Arduino IDE with the intention of teaching my girls Control theory.  I have decided I would use this environment to develop the Oven Controller.

Maxim make a brilliant, if not slightly pricey Type K thermocouple digitises.  it uses the SPI interface.  ryanjmclaughlin has created an Arduino Library for the MAX6675.  

Brett (aka br3ttb) had created a PID Library – Some may say all the fun has gone.  Well maybe, but I still get to pull their work together and make my oven how I want it.  I will be adding an LCD to give feedback on where you are in the cycle. Graphic would be super – otherwise 2×16 will be OK.

Update 1

Thermocouple Nut

Found an old thermocouple from a previous Jaycar project.   The Type-K thermocouple is constructed with a 3.2mm Diameter Stainless Steel barrel and is an exact match for the MAX6675 for testing.  I am not sure if this will be the final one I will use but for now it will suffice.When I was in the workshop, I realised how easy it would be to make a mounting nut for the thermocouple.  Starting with a 3/8W bolt, I drilled a 3.2mm hole through the middle.  I then drill a pilot hole in one the bolt head flats and tapped it with ISO M3.

Thermocouple with Nut installed

The MAX6675 performs cold-junction compensation  and digitizes the signal from a type-K thermocouple. Direct
The data is output in a 12-bit resolution, SPI™-compatible, read-only format.
This converter resolves temperatures to 0.25°C, allows readings as high as +1024°C, and exhibits thermocouple accuracy of 8LSBs for temperatures ranging from 0°C to +700°C.

  • Digital Conversion of Type -K Thermocouple Output
  • Cold-Junction Compensation
  • Simple SPI-Compatible Serial Interface
  • 12-Bit, 0.25°C Resolution
  • Open Thermocouple Detection

K type Thermocouple based Thermoneter


Whilst I await a Solid State Relay to come in, I have stated looking at the final schematic.  I have allowed for two LCD modules.  Currently I am testing in 4bit parallel mode, but would like to try a 3wire SPI display.  the final design will only have a single display.
Follow features have been included:

  • Nokia cable USB debug port
  • Soft Power LED
  • Heater Status LED
  • DC Power supply requires attention
  • Off board Solid State Relay – I am looking for a “Puck” type
  • Emergency Stop to be implemented, either contactor or  uController Interrupt

Continue reading →

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4Channel Dmx DC Controller

Posted on September 5, 2010 by admin

I have a couple of RPM’s 4ch AC DMX SSRs.  They are a great concept for when you need a small channel count in a remote part of your display.

I predominantly use LEDs for displays. This means DC is king.  So recently I set out to build a simple DC controller that would need to be small and have reasonable switching capabilities.

I cam up with this list of requirements

  • Smaller is better
  • Minimum of 2 Amps per channel
  • Input supply voltage to be a minimum of 36Vdc, 48Vdc if possible
  • Standard Diag lights
  • Surface mount components

A couple of weeks ago, Rockby Electronics‘ weekend sale listed some small bulkhead plastic cases for 75 cents each.  That was a steal!  I bought 80!

The following story details the approach I took to create what will be the end result, starting with the initial PCB Design.

The Design has progressed somewhat.  The final layout was changed somewhat to allow better cable entry from the box.

Top View of Semi populated Controller

 

 

 

 

 

 

 

 

To make assembly easier, I had the PCB made in panels of 6.

Panel - Bottom Side - All SMT

Panel - Top Side - All the Leaded components

 

 

 

 

 

 

 

 

 

 

 

So how does it Perform?

 

 

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Control Theory

Posted on August 12, 2010 by admin

We home school our younger two girls. Rose, who is in year 7 (Stage 4) is doing Science & Technology. A lot of home schoolers in our area really get into the control theory, make great use of Lego Mindstorms.  Since the Ardiuno hit the streets a couple of years ago, I thought we would go down the line follower track using a suitable platform.

I will be using this simple machine as the main aid to teach the Control Theory section.

Now I have the platform, time to start completing the subject programming material.

Unpacked the rest of the material I received.  Just to give you an idea of the variety of patforms, we have Qty 1 as shown above.

Qty 1 - ETT Tank

Qty 2 - ETT BIG Wheel Kit

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Simple RGB Controller

Posted on August 5, 2010 by admin

I recently discovered a great little chip the WS2801 from World Semi.   the manufacturer describes it as a 3-Channel Constant Current LED Driver With Programmable PWM Outputs.

That is a mouthful.  Basically a 24 bit serial shift register driving a free running PWM and 3 constant Current Drivers.

They look super simple to drive.

I am thinking it would be super cool to use as very small remote light controller.

Remote WS2801 Controller

So far the costing is
WS2801 0.20
AM26LS32ACPWRG4 0.54
UA9638CDR 0.33
Lo Profile RR45 2.00
PWB 1.00

Gut feel is it will need to be below $5 to be viable.

WOW!  This idea was originally posted in August 2010!

The concept just won’t leave.  I have continuely returned to the the concept, but I find the solution is growing.  How about a family of WS2801 baseboards  in 3, 6, 9 or 12 channels a,d a couple of Interface boards that run either SPI over RX485, DMX or even Komby Wireless?

I see the I/F boards fitting in a 50x50mm  and will sit on the baseboards so the RJ 45s are on one edge.

– More to Come –

 

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Sydney DIYChristmas Mini

Posted on July 25, 2010 by admin

Well today was our “Sydney Mini”.

We all arrived to the great venue, the Upper Hawkesbury Motor Boat Club

Yep the Venue was excellent – and it was some what confusing to arrive to a car park full of collector’s bike, I am sure I wasn’t the only one who sort wished I could join the ride.

Mini High lights included:

  • AVR & PIC programming basics
  • DMX introduction
  • VIxen & LightShowPro basic sequencing
  • “Ethergate” Introduction Joshua 1’s implementation of a E1.31
  • RGB Pixels and CCR comparison
  • We saw three different LED Floodlight versions, a true DIY home made wire frame train with self coloured rope light and couple of  original 595 vero boards

Dave, you’re a champ for arranging the venue.

Guys thanx for making the mini what it was, simply superb.

All that attended concluded to make this a common event at the same venue.  The preferred timing is April/May so stay posted for the next one.

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LED Mega Tree

Posted on July 21, 2010 by admin

At the end of the 2009 season I decided it was time to build a LED Mega Tree.  A Mega Tree is best described as a display item that outlines a traditional tree shape using strings of lights hanging from the top of a mast to the bottom at equally spaced distance around the base.  There are many examples on the net – Mega Trees have become a basic item for most displays.  Each string of light is individually controlled enabling all sorts and affects to be displayed.  Generally multiple colours are used allowing more thematic displays to suit the chosen music track.

The are 4 critical components to a Mega tree:

  1. Dimensions
  2. # of Channels
  3. Colours
  4. Construction

Continue reading →

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Design for Manufacturabilty

Posted on July 19, 2010 by admin

This is a topic I haven’t read about for some time.  I recently was searching the web for wave soldering and came across this fantastic article.  It’s production is pretty low tech but the content is worth a read.

check out Altron’s Board Guidelines.

it has useful information of how  to create component footprints in any CAD package and how to lay out a PCB for optimal manufacturability..

I have no association with these guys, hell I don’t even know who Altron Inc is, and offer the above link for self education only.

If you find a better document send me a link.

A fellow member at DIYChristmas.com mentioned the following as a good reference.  David L Jones is a bit of a larrican from here is Sydney and has made his fame with interesting video blogs.  Check out his Design Guidelines

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TOT – SMT pens

Posted on July 7, 2010 by admin

Tools of the Trade

I like using Surface mount components where ever I can. But I have to say the size of those devilish small components can be a real pain. Picking them up is always an issue and most the time a decent pair on non-magnetic tweezers will do the job. I recently purchased a SMT pen like the one below.  (I will replace the photo with the real one latter).

Surface mount pen

I recently came across an web site will all sorts of great DIY tips including how to make your own SMT Vacuum pen. Check out Ken article here.  It almost makes you want to go out and buy a cheap fish tank pump just to try it out.

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The Wonders of Sight

Posted on July 6, 2010 by admin

I recently purchased a USB Microscope from a seller on Ebay.  check out the sellers  200x C2M 2M USB Digital Microscope endoscope Magnifier.

Other than the clip being broken I must say I was super impressed with the build standard of the product and the quality of the pictures / video.  the following clips were taken with the camera in Capture mode.  Neat hey!

USB Microscope Clip 1

USB Microscope Clip 2

USB Microscope Clip 3

Over the coming week I will be using this Scope to teach my two home schooled kids science.

Of course you can also expect the tool to be used in this hobby too!

Update 8/07/2010

Got say i am disappointed with the seller.  I got a request to send the whole lot back to China for a replacement unit.  That will cost me another $28.5 in postage and packaging

and them about the same to send the new one.  That is more than the camera is worth, all because of a small broken clip.  Disappointing indeed.  Plus I miss out on using for 3 weeks.

I am hoping common sense will prevail and they will just send a replacement clip.  If needs be I will continue to use a Microphone holder till it gets sorted.

Not related to my dispute with the seller – I can confirm these beauties don’t work with Win7 -64bit!   Grrrrrrrrrr.

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