L20 Amplifier

Solder Side of PCB

Solder Side of PCB

3D view of DC filter Board

3D view of DC filter Board

Component Side of PCB

Component Side of PCB

PCB with the Resistors Loaded

PCB with the Resistors Loaded

PCB with all components loaded bar the Power Transistors

PCB with all components loaded bar the Power Transistors

Sellers view of the Amplifiers

Sellers view of the Amplifiers

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Is Islam a religion of tolerance – or one of discord and prejudice?

Read a really good article relevant to today!

Highlights include:

“But if Islam does stand for freedom of faith and coexistence, why is it that so many people who call themselves Muslims are in so much conflict, not just with non-Muslims, but also with other people who call themselves Muslim?”

“If you believe that Muhammad is your moral guide, then you have to accept that there was a peaceful character in Muhammad and that there is a warlord, a military man, a beheader, a man who sold people into slaves,”

“While the Western world now largely accepts a live-and-let-live ideology, it was not that long ago that religious intolerance was our norm, too.”

“Not only did we have the medieval Crusades but we also had the confessional wars of the 16th and 17th centuries.”

“Intolerance lived on in the 20th century in my birthplace of Ireland, where extremists like the late Ian Paisley denounced the Pope as the Antichrist as late as 1988.”

“No Indonesians or Muslims were killed in revenge attacks in Australia.”

“But a little over a year later we had the Cronulla riot. Disgusting as this event was, no-one was killed or seriously injured and police action was admirable.”

“But many self-appointed Islamic spokesmen give no credit to this liberal tradition.”


Read the whole article here:


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YAEL (Yet and Other Electronic Load)

I stumbled on to Kerry Wong web blog when I searched for some ideas on an electronic load.  Kerry also references a tutorial on an Electronic Load for testing batteries by Dave of EEBlog.
Kerry uses a lm324 to drive 6x fets. As I am wanting a lower capability, I will be only be using 3x fets.

eLoad Schematic GeneralLayout1 GeneralLayout2 GeneralLayout3 WorkingLoad


I am aiming at the following Specifications:

  • Load voltage range: 0 to 30 Volts
  • Load current Range: 0 to 10 Amps
  • Operation Voltage: 12 Volt

The heat sink is 100x50x15mm. I choose this one as it is easy to retrofit 2x 40mm fans.

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EBAY 10Watt LED Flood Light Retrofit

My 20Watt Roll your own RGB Flood Lights take a lot of effort to build.

I purchased some 10Watt LED Spot lights from EBAY.  They are reasonably made and very compact.  I also purchased some LED Constant Driver boards from AliExpress.

The intention was to replace the 10Watt White LED with a 10W RGB Chip and then “blob” the Drivers.

I ended up creating a little 3Ch Constant Current Shield from my RGB Kitty Pixels.

Ebay-LED-Flood AliexpressCC-Driver KittyConstant-Current_Bottom Kitty-CC1 KittyConstant-Current_Top Kitty-CCPOC2 Kitty-CCPOC1
Ebay 10Watt Led Flood Light


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Out with the Old, and – What was I thinking?

Going trough display items, making sure they still work, replace the odd LED where needed etc, I very soon realised I still needed a SSR base controller.  the old control centre had two such controllers, one my first design, a sub rack based 16 Chan LED DMX module, and the other was a RPM Grinch Dimmer.  Having ditched the old control centre I very quickly decided I needed to roll an new solution, or repackage one anyway.


Internal View of 16Ch LED DMX Controller

Internal View of Quad Isolated DMX Splitter

Internal View of Quad Isolated DMX Splitter

this final phot shows the 2 vesion I did of the 16Ch LED Controller and the finished DMX Isolated Splitter.
A stack of Controllers

A stack of Controllers

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Out with the Old, In with the New

This year I am upgrading my control center.

Gone is the IBM ThinkCentre, the 192 Channel DC DMX sub-rack, the Grinch Dimmer, the USB DMX adapters and the couple of modified PC power supplies.
The new Cabinet contains 3x 350Watt SMPS and Falcon Pi Player will sit on top for the season.

ControllerCabinetOld2 ControllerCabinetOld ControllerCabinet3 ControllerCabinet2 ControllerCabinet1
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Temperature controlled Fan

I finally finished one of the outdoor Power Supply Boxes.  It contains 2x 350W SMPSs in it and will be situated in the garden.  The cabinet currently has a 12v computer fan to push air out of the box. Like all good computer fans this one makes a racket.

So I have set out to make a simple fan controller.

Design Requirement:

  • Operate of 12Volts
  • Keep fan OFF until needed
  • At 40degree ( this is my first guess) turn the fan ON slowly)
  • At 60degree and above make the fan go flat tack.
  • Between these two set point, the fan speed is to be set proportionally
  • Capable of driving 3 80mm or 120mm fans

the Temperature measurement can be super easy using a thermistor is a basic voltage divider. I have Atmel ATTiny 13 what have ADC and PWM functions.

Update 1:

I scraped the Thermistor idea and went straight toe Dalas DS18S20.  I have a number left over from a previous project.

Basic Schematic

Basic Schematic






 Now for the PCB Layout too

PWM Fan Controller PCB Design

PWM Fan Controller PCB Design


Partially Built Fan Controller

Partially Built Fan Controller

Lastly for the Code



Update:  Below are a several cooling options installed using this fan Controller.

ControllerCabinetCooling2 ControllerCabinetCooling1 ControllerCabinet2 ControllerCabinet1
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Press Bender

Being an avid DIYer, I always find the need to bend up brackets, even if it is a simple 90 degree bend bar.  Quite often a trip to the local hardware store will reveal suitable substitute brackets.

I stumbled on Swag Off Road 20 ton press brake.  Kool,  if only they were available here in Australia too.

They say “Necessity is the mother of all invention”.  Watching the video a couple of times, got me thinking, what would it take to make a similar unit?  So the long process of considering all sorts of solution starting to roll through my mind.  Some got sketches, some didn’t make it that far.  At one point I realised I don’t need a massive solution and the 20 ton press was probably a bit of an overkill not to mention where I would store it.

2 significant occurrences happened:

  1. Whilst in Machinery House getting a disposable Argon Shield regulator, I found 125mm Vice Brake bend jaws
  2. I stumbled on a 6 ton Bench top press on the web

Having acquired two sets of jaws and a press, this is how I went about making my very own Bench Top Brake Press Bender.

ViceBender1 ViceBender2 ViceBender3 ViceBender4 ViceBender5 ViceBender6 ViceBender7 ViceBender8 ViceBender9

As of today, the unit is built and tried.  I have already planned a few modifications to make it better:

  1. The punches for the jaw benders are razor sharp.  This might be good for sheet metal, but I found bending 2mm Alum to 90 degree lead to about 40% failure.   I had to flatten the punches to a 1.5mm or so on the bench grinder.
  2. The wheel nut works very well as a spacer – the conical dome seats the spring very well.  I need to source two identical wheel nuts so the springs apply even tension
  3. It would be really good to some how fix the base to the side rails

If I had my time again I would extend the inner shafts and tread the ends.  This will enable a lock nut to be added to prevent the top and base separating.

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Fuse sizing

Math alert:
My spiral trees have 42 pixels. That means 42 x3 =126 LEDs per tree.
2 trees are connect each controller. That means controllers have 252 leds.
So if we allow 20mA per LED.  That comes to a total of
252 x 0.02 = 5.04A.
* controller fuses have to be 5 Amps.

The spiral trees operate at 5v. To save on voltage drop I will run 12v to a small 10A dc dc converter that is located close to the controllers. 2 controllers will be connected to a single dc dc converter. That means it will supply 10.08Amps
10.08×5/12= 4.2Amps at 12v. (Assuming perfect conversion)
Realistically there will be about 20 to 25% loss.
4.2 / 0.8= 5.25 Amps or 4.2/0.75=5.6 Amps.
* dc dc converter
fuses have to be 5 Amps.

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4Channel Dmx DC Controller – Revisited

4Ch DC DMX Original

4Ch DC DMX Original

4Ch DC DMX Artwork

4Ch DC DMX Artwork


4Ch DC DMX Controller – 1st Prototype

I have previously designed and built a 4 channel DC DMX controller. This controller has served well. But I needed to do a quick update for some display items.

Firstly I needed to add RJ45s.  They take  up a lot of real estate.

Second, I wanted to add a simple Molex connector

Thirdly, I wanted 5.5mm DC Power Barrel connector for Power in

Fourth, I updated the fuse to the Mini Auto blades

Fifth, I decided to look for some smaller devices and have been taken with the DMN6040SSD-13 yu Diodes Incorporated.
In short, the specs are:

Dual N-Channel, Vds=60 V, Id=4.4 A & Rds On =55 mOhms (Vgs =4.5V)
Package/Case: SOIC-8

Finally I wanted to try a reed switch as the way of changing the Start address. To arable this, X8 and X9 were added.

That pretty much wraps up the change

BTW I can already see some more changes. Some of the Text is mirrored. that is what happens when you have components on both sides.
I reckon I might swap the location of H1, H2 and C6

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