Oct 31

Micro SD, Macro Packaging!




I thought this one deserved a blog post, not exactly a hobby of mine but worth a look none the less.

It’s a great example of waste in today’s society… tiny little SD card in a huge packet!

The only reasons i can think of for this is either:

  • to make it harder to steal or:
  • to make it more visible as an advertising attempt.
Micro SD Card

Micro SD Card

Good one Verbatim!

Aug 07

Nexus 7 Car Installation




What more could a gadget-addict want than to have all the features of Google’s latest flagship tablet, the Nexus 7 embedded in the dash of their car?

I quickly got bored with off-the-shelf car stereo systems, here is my response:

I have installed a Google/Asus nexus 7 in the dash of my MY00 Subaru WRX. I trialled the optus mytab (AKA ZTE V9) in the dash but it didn’t last more than a day since it was a piece of crap performance and audio-wise.

After spending a few months building a nano-itx double din touch screen pc to go in the dash, i changed my mind (for the millionth time) and decided to stick an android in there instead. The intel PC is now sitting in a box at home doing nothing…

The biggest trouble was finding a tablet that would fit in below the A/C controls nicely.. in the end, the N7 was about 3mm too big bit i broke out the dremel and made it fit!

Parts list:
ASUS Google Nexus 7
4 Channel Nakimichi Amplifier
Single Channel Class-D 1000W Nakimichi Subwoofer amplifier
Four-Gauge power/ground
Gold plated Ground splitter and +12v Splitter/Circuit Breaker
Oxygen-Free Copper speaker cables (around 12 gauge)
(coming soon) 1.5 Farad Capacitor (to stop headlights dimming)
2 x Kenwood 1200W Subwoofers
4 x Focal 6″ Splits
Good quality RCA cables
R/A 3.5mm headphone plug to 2x RCA 30cm cable
R/A Micro USB cable
gutted tomtom GPS charger
(coming soon) RCA volume level control (thanks for the idea ahavens17)
20mm wide metal strips
Hook and Loop velcro
Rubber trimming/edging

Update: Added some more pics showing my crude but effective way of holding the tablet in-place.

To hold the tablet in place, i have used some metal straps cut to size that are screwed on using the screws that hold the top of the ash tray to the dash fascia. I stuck some velcro on to the metal straps and 2 small strips on the back of the tablet to dampen vibration and stop the tablet sliding around sideways. The velcro also stops the metal straps from marking the back of the tablet (not that it matters since it is hidden behind the dash)

You can see how it is done in the pictures above. Also, I am using right-angle micro USB and audio connectors so that they fit nicely in the dash.

Update: Nexus 7 is off for replacement

Unfortunately, i had to return my N7 under warranty because the USB port slowly failed to function. At first, it charged really slow, then it wasn’t able to connect or be recognised on any of my computers and then it stopped charging altogether so i sent it off to google. The good news is that the replacement should arrive in a few days!

Jul 10

Lemon Myrtle Soap




Due to my keen interest in gardening and also science, I like to distil essential oils from plants (I will describe my distillation hobby in another post). I take the trimmings from plants that i grow and rather than throw them in the compost, i run them through my steam distillation apparatus and extract the volatile oils from the plant matter.

After extracting a few different types of essential oils and not having much of a use for them other than oil burners and eucalyptus oil for it’s cleaning/solvent properties, I decided to try and find another use for them. The outcome of my brainstorming was to make soap!

Home-made soap would make a great christmas gift, saves money if i use it at home and is fun to make!

I chose to use Olive oil and refined coconut oil as the base, lemon myrtle fine ground leaves and essential oil for scent and exfoliation and green Argiletz clay for colour. This method is called “Cold Process” soap making

Lemon Myrtle Soap

Lemon Myrtle Soap

The recipe was somewhat like this:

Ingredients:

  • 800g Extra Virgin Olive Oil
  • 200g Refined Coconut Oil
  • 350g water
  • 130g Sodium Hydroxide (caustic soda/lye)
  • 1/4 cup Lemon Myrtle leaves finely ground
  • 15g Lemon Myrtle essential oil

Method:

  1. Add caustic soda to 350g water (don’t add water to caustic soda unless you want dangerous mess all over the place) the mixture will heat up rapidly and give off nasty fumes so do it outside. Let the mixture cool a bit as you do the next step
  2. combine olive oil and coconut oil in stainless pot on the stove, heat until it is about 55 degrees C
  3. using a stainless thermometer, measure the temperature of the oil and the caustic soda solution, when they are between 40 – 50 degrees C, combine them by carefully pouring the caustic into the oil. If the oil cools too much, you can reheat it lightly but don’t reheat the caustic. If the caustic gets too cold, you are better off remixing a new batch.
  4. using a combination of a stainless shaft stick mixer and stainless stirrer, mix the oil and caustic together until light trace (trace is when you can pour a little of the mixture over the surface and it will sit there for a few seconds before dissolving back into the mix.
  5. now is the point where you mix in the essential oil and leaves, combine well by hand stirring with the stainless stirrer (you  don’t want to mix it too much, that’s why you don’t use the stick blender)
  6. carefully pour the soap mix into an empty 1L milk carton and close the top. wrap lots of towels around the milk carton as insulation so that it doesn’t cool down too quickly and set aside until the next day
  7. after about 18-36 hours, tear off the milk carton and slice the soap into blocks, my recipe made about 11-12 good size blocks of soap.
  8. place the soap blocks onto a rack to dry for 3-6 weeks, turn them over about once a week.

Notes:

  • Be really careful when dealing with caustic soda, it is very dangerous and can cause severe burns. Wash it off thoroughly and immediately if you spill or splash it anywhere. White vinegar can be used to neutralise the caustic effect.
  • don’t use pots/pans/mixers/etc that you intend to use again for cooking. go and buy a cheap set of equipment that you can keep specifically for soap making
  • always use a soap calculator to work out how much caustic soda to use for your recipe. Here is a simple one: http://www.australiansoapmaker.info/ozcalc/lye.php
  • be PRECISE when measuring out oils/caustic soda/water, the results will be severely affected if you are not exact in your measurements.

Jul 06

Killer Seed Propagator

Do you want to know how to increase your success with seed germination? Read on!

As the title of my blog implies, I have way too many hobbies and gardening/hydroponics is one of them!

I set out to build a seed propagator that would create the perfect environment for my precious seeds. It takes care of warmth, watering, light and humidity and is very very simple to build! The system has a small footprint but a high density so that you can grow lots of seeds.

Complete Seed Propagator

Complete Seed Propagator

The design is based on a flood-and-drain (aka ebb-and-flow) system where the lower reservoir holds water or a nutrient solution (plant food) and the water is pumped up to the top tray via a small submersible pump every few hours wher the seed tray soaks up the water it needs.

So that the tray does not overflow, there is an outlet set at a good height that lets the water drain back into the reservoir and recirculate through the system.

Once the pump is switched off, the water drains back out through the pump and lower outlet.

Flood and Drain

Flood and Drain

Since i opted for a more water-tight design, there are rubber grommets around all the fittings to stop leaking. The problem with this is that there will be a tiny amount of water remaining in the top tray after it has drained because the tray is flat.

If the seed trays were placed directly on this puddle of water, they would not have a chance to dry out. Soggy growing media leads to seed rot and mold which is not good for your sensitive seeds.

To solve this issue, i placed another slotted tray inside the top tray so that it sits slightly above the residual water level and allows the growing media to drain sufficiently.

Draining Tray

Draining Tray

Heat is provided by a propagation heat-mat placed underneath the whole system. This provides a good temperature to the water reservoir which couples heat up to the seed tray. This also helps to reduce shock to the seeds caused by watering with cold water.

Humidity is taken care of by a clear plastic top with adjustable vents. This type of lid can typically be found at your hardware store or nursery. It is generally called a humidity dome or similar.

The humidity lid also provides a solid surface to place a compact fluorescent light on for rapid and sustained growth as soon as your seedling exits it’s seed case.

Complete Seed Propagator

Complete Seed Propagator

Light is provided by a low-wattage compact fluorescent with the correct light spectrum for seedlings. It was bought from my favorite shop . Darren and Brett really know their hydroponics and are more than happy to help or just have a chat. If you are local to canberra, i would really suggest you give them a visit at

2/84-86 Wollongong Street Fyshwick ACT 2609
(02) 6239 2598

As a trial run, I have planted Pepper (Piper Nigrum), Lemon Basil (Ocimum × citriodorum), Thyme (Thymus mongolicus) and Ghost Chilli, aka Naga Bhut Jolokia, recognized by Guinness World Records as the hottest pepper in the world.

When the plants start to grow, i will update this blog with pictures and how successful the hydroponic propagator is at germinating seeds.

Jun 21

Resize Raspberry Pi Partitions

Sandisk 16GB SD Card

Sandisk 16GB SD Card

If you downloaded the default Debian image for your Raspberry Pi and burnt it to an SD card bigger than 2GB, chances are you won’t be using the full capacity of your storage card.

The default image creates a small boot area (about 75mb), a root partition a bit smaller than 2GB and a 200mb swap space.

Soon after installing a few packages on my Pi, I ran into strange issues like log files not being created, files not downloading, etc. I started noticing errors like “No space left on device”. Using the command:

 

df -h

i could see that my SD card was completely full.

Here is an easy method to resize your Raspberry Pi’s storage card to utilise all of that wasted space.

What you need:

  • A Linux computer
  • A Raspberry Pi
  • An SD card reader/writer
  • GParted – Gnome Partition Editor

Install GParted

You should be able to find GParted in your default package manager. For Fedora/RedHat based systems use yum:

yum install gparted

For Ubuntu/Debian systems:

apt-get install gparted

Re-partition your SD card

This is the dangerous section. ALWAYS make sure you have a full backup of anything important or you may find yourself re-creating your Raspberry Pi card again.

That said, Fire up GParted and select your SD card in the dropdown (top right).

Select your SD card

Select your SD card

Next, select the linux-swap partition, we are going to move this to the end of the volume. Select Partition -> Resize/Move

Copy the value from “Free space after” to “Free space before” and press Resize/Move

(before) Move swap partition

(before) Move swap partition

(after) Move swap partition

(after) Move swap partition

 

 

 

 

 

 

 

Next, select the big ext4 partition and bring up the Resize/Move window. Change the “Free space before/after” both to 0 (zero) and press Resize/Move

(before) resize root partition

(before) resize root partition

(after) resize root partition

(after) resize root partition

 

 

 

 

 

 

 

Make sure your partition scheme looks something like the following image and when you are happy with it, press the green tick to start the process. This takes about 5-10 minutes depending on the size of your SD card and then you are free to put the SD card back in the Raspberry Pi and make sure it boots.

All done!

Final SD card partitioning

Final SD card partitioning

Jun 19

Simplest Raspberry Pi Case Ever

After recently acquiring a model B raspberry pi (finally!), i set out to build a case for it.

The goal was to make something that

  • protects the Pi from damage
  • Is  heavy enough that the weight of the ethernet cable does not pull it off the back of the desk
  • looks presentable.
Simplest Raspberry Pi Case Ever

Nice and tough 10mm Acrylic

Standoff Assembly

Standoff Assembly

 

 

 

 

 

 

 

 

I have been making lots of things with acrylic lately after discovering Plastic Creations in Fyshwick. It is a fantastic material to work with on the CNC after you learn it’s characteristics.

I chose to use 10mm thick acrylic for the Pi case because it is tough and pretty! I machined out 2 slabs about 120mm x 70mm  with holes in the four corners. The slabs are held apart by 25mm stainless steel stand-offs (*AKA Advertising Nails) which i got made in China for me.

Stainless Standoffs

Stainless Stand-offs

To buy something similar here in Australia was $19 PER STANDOFF! whereas i got them from china cheaper..

Next step was to polish the acrylic edges to remove tooling marks. I ran through 180-grit to 400-grit sandpaper and then”Flame Polished”the edges with a LPG/Oxy torch. The flame is run over the edge of the acrylic quickly enough that it lightly melts the edge without bubbling it, and the result is a nice shiny finish!

Finally, i buffed the edges for a bit of extra shine with brasso and put it all together.

I still need to work out a better way of securing the raspberry pi in the enclosure since double sided tape just feels a bit dodgy when the rest of the case is so pretty!

NasPi

Network Storage Server

EDIT: As you may see in the comments on this post, there is already a similar case out there (very very similar in fact), the major difference is that the designer has a brilliant way of holding down the Raspberry Pi inside the case.

Great minds do think alike!

A link to PI-STACK on eBay by Ken Dakin.

And a review of his excellent product by Peter Vis

I don’t intend to market my case as i think that would be quite rude considering Ken Dakin already has a product on the market but if you would like to get one for yourself, i would highly recommend you buy Ken’s PI-STACK.

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