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

18S20Tiny13Fan

Enjoy.

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

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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.

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

4chDC_DMX_Rev3_Assembled

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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8 Channel RGB LED Flexible Strip Controller – Revisited

I have previously designed and biult a 8 channel RGB strip controller.  This controller has served well.  But sadly the output transistors have gone End of Life.

Artwork Design

Artwork Design

I did two things to rectify this situation, I found a replacement device and ordered 500 to try out.  I also decided to look for some smaller devices and have been taken with the DMN6040SSD-13 yu Diodes Incorporaate.
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

DMX_8ch_LED_Rev4_Assembled

1st Prototype

 

 

I also added a couple of fuses , Rj45s and dropped the switch mode power supply for a simple linear.  For 12Volt operation this is fine.  for higher voltages, I will change the LM7805 to Murata Switcher.

 

– Now to test the unit.

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DMX Terminations

DMX512 employs RS-485 differential signaling at its physical layer.  DMX512 uses a unidirectional simplex communication protocol.

the following is a paraphase from Wiki:  DMX512 is a bus network that works upto 1,200 metres long, provided you don’t have  more than 32 receivers on a single bus. If more than 32 recivers are needed in a single universe,  it can be expanded across parallel buses using DMX splitters. DMX wiring  consists of a shielded twisted pair, with a characteristic impedance of 120 Ohms, with a termination resistor at the end of the cable furthest from the controller to absorb signal reflections.    Go read some more here.

Wiki also has a realy good graphic Simple DMX Network Bus

Traditionally the christmas lights fraternity add DMX terminators to each controller withe link pack to select the terminator if it the the last one on the bus.  I have added thenm to most of my designs too. For example X10 on my 8Ch DC Controller.

But here’s the rub.  I never fit the link packs.  I too lasy. and then I forget which one has the terminator installer.  So I so a for more visual termintator.

These terminators are a cinch to make and are pretty reliable too. the cost is super good.  the last lot cost me 6.5 cents each.

Material:

  • RJ 455 plug
  • 120 ohm 1/4W Resistor (1/8 W also work)
  • scrap Cat 5 wire insulation
  • hot glue ( optional)

Proceedure:

  • Bent one end of the resistor lead back over the body of the resistor.
  • Place the resistor on the outside of the body with the two leads alnign with the pins.  You want the body of the resistor to be just an the end of the pins.  Trim the leads.  I trim mine to XXmm.
  • Add some scrap Cat5 wire insulation to the resistors leads before inserting hte resistor in the connector housing and crimping.
  • Once your done, your can add a blob of hot glue or silastic the seal the end.

Just a coupleo of notes:

  1. 1/8W and 1/4W resistors are small and have 0.4mm diameters leads which is a tad smaller than Cat5 (0.51mm)  the body is also small enough to fit inside the connector housing
  2. There are two types of connectors dependant on your cable type, solid or stranded cable.  Try and purchase some connectors suitable for solid wire for this project.

 

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Finally Affordable Snowfall Tube rebirthed

FAST was created by Cory Helmuth as a inexpensive snowfall or meteor tubes. Snowfall tubes are long clear plastic tubes that have a group of LEDs arranged in a linear fashion and the LEDs light in a sequential manner from the top to the bottom. The visual effect looks like a bright snowflake falling down. The FAST consists of a FAST Controller PCB that drives 1-8 LED Segment PCBs each with 7 LED’s per segment for a total of 7-56 SuperFlux LED’s. Based on the number of LED Segment Boards used, the snowfall tubes can be between 12″ to 48″ in length.
The FAST is designed using a concept called Charlieplexing.  Charlieplexing, in its simplest form, works using a matrix of complementary pairs of LEDs. This allows a large number of LEDs to be driven by a small number of I/O pins from a PIC microcontroller. In the FAST, 56 LEDs are controlled using just 8 connections!

Check out full details in the Wiki over at DIYC.com

I purchased a number from the guys at diyledexpress

I found the controller PCB too big to fit in the tube I sourced, so had to repurpose the Controller PCB.

Initially I used strip board to.

Eventually I decided a small PCB would make things tad  easier.  This article details how I progressed.

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RGB Window Outlines

Window outlines are a popular display items. They accentuate the house beautifully.
There are two things you’ll discover when installing windows lights – String length might be a problem, and tape won’t hold them. Whether you’re putting lights up inside or outside your windows, there are solutions available on the net.
I used Rope light for a number of years, but they tend to droop in the middle and the corners end up rounded.
This year I am adding a more officiated design that uses RGB LEDs.

20mm Tigh Elbow

20mm Tight Elbow

The main concept is to build a free standing frame that sits inside the brick surrounds of the window. I discovered Air-conditioner tight elbow at my local electrician supply shop. These elbows are usually used for removal of the condensate on hot days. They also make straight tees too. And they fits normal light duty conduit.

The RGB LED strip was purchased from AliExpress.

These are the actual ones I purchased.  I scored them on sale as great sale.

These Window outlines are designed to be completely dismantled for storage.

20mmStraightTee

20mm Straight Tee

Material List
20mm Light Duty Conduit
20mm Tight Elbow
20mm Straight Tees
40mm Clear HeatSrink
Non-waterproof RGB Led Strip
RGB Strip connector tails
Spray tin of PCB Laquer
1m x3mm Bungee cord
3mm Polyester cord
3mm wire

Method I used

Measure the window opening and subtract 10mm.

PCB lacquer

PCB lacquer

Take conduit offcut and grease up the outside. Place conduit into the elbow.  Measure the distance from one edge of elbow to the other.  My elbows measure 45mm.  Remove the conduit and measure how far the grease smeared up the conduit, in my case it was 20mm.  This means I needto subtract 25 +25+10 mm = 60mm shorter than the window measurements

Cut 20mm conduit to length to suit the window less 60mm.

Carefully unroll the RGB LED strip and trim to maximise the lead.  Remember you need to allow 20mm that slides in the elbow.

Solder the RGB 4 core tails to both ends of the strip.  Apply the PCB Lacquer onto the LED strip.

Now the Fun Starts.  Sliding the clear  heat shrink over the conduit and LED strip can be difficult.  However after the first attempt, I discovered applying a very very light amount of Olive oil on the back of the conduit made life extremely easy.  I dip my finger in extra virginal oil and smear it on the back.  I only dip my finger twice over 2 metre of conduit.  I just keep running my finger up and down the conduit .  The clear heat shrink glides on.

When the sides have been completed, it is time to do a trial run installation.  All is good, Yes?

As stated previously, I want to store these completing broken down. This means I need a mechanism to hold them together for the whole season, I decided to use bungee cord inside the conduit.
I use 3mm bungee cord to keep the frame together. Measure the frame perimeter. cut the cord to the perimeter less 1.5meters. Knot a loop on one end. Tie a 1 metre length on bungee cord to the other end. Add a hook to the other end of bungee cord. Using 150mm of 3mm wire form a “U” there will slide into the conduit. Bend 30mm of the wire ends back on itself to prevent the hook sliding completely into the conduit. Hook the cord on the wire hook and feed the bungee cord and rope cord into the conduit and elbow pieces. the last bit is a bit tricky, you need to extend the bungee out of the far end and hook on to the cord.
See below for a photographic record of construction.

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Mini Pixel Trees

Spiral Planter Cage

Spiral Planter Cage

Based on 900mm Tomato Cage frames and 42 LP6803 Pixels, these trees have been a very very long project. The project started almost 6 years ago when I purchased for plant trellis cages from the local nursary, for the garden. Every time I looked at them in the garden I thought it would be cool to purchase some more. after about 6months I head back to place an order to 8 more cage, only to be told I was mistaken, I could’ve purchased them from them, cause they have only every sold 1200 and 1500mm cages. Well Bugger me I said, (on second thoughts may be not). Proud to say I haven’t been back to that local nursery. But I did note the manufacturers name on the 1200mm cages. Within 2 months I took delivery of 8x 900mm new cages, sporting the new colour range of mucky brown, directly from the distributor, who was only too happy to supply them directly when I explained what happened.  He even ventured to suggest he wasn’t surprised!.

These are my materials used:

  • 900mm obelisk Spiral plant supports
  • 1x Pixel string, I used 42x pixels with LP8603 for these
  • 2m x 4core 14/2 alarm cable
  • 1x 4core pixel tail
  • 100s of UV stable cable ties
  • 1/8″ wire to extend Spiral

See the photo gallery below for construction details. Note the manufacture of the cages didn’t continue the spiral all the way down to the base. I found it necessary to add a small section of 3.2mm wire to complete the spirals.

I also glued some Star Plugs onto the cage ends to prevent them from sinking into the ground.

So that is that.

 

And here is a video running a static RGB Fades

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The Falcon Pi Player and a Real Time Clock

The FPP only has two option for RTC. A Rasclock and a DS1305. None of these seem to be available here in Australia. Bummer!

But SunFounder DS3231 RTC Real Time Clock Module seem to be all over Ebay for a couple of bucks.
DS3231rct1

DS3231rct2

Even DX.com sel;ls them http://aud.dx.com/product/ds3231-raspberry-pi-rtc-board-real-time-clock-module-for-arduino-black-961277258#.U3VmhCiBtuY
They are tiny. And these guys have got them going on the Pi
http://nicegear.co.nz/blog/using-an-i2c-real-time-clock-rtc-with-a-raspberry-pi/
So I will try also.

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