Light with no sense of proportion

This is a slightly silly project brought about by a slight interest in bigger brighter faster and louder things.

Some friends of mine and I recently purchased a piece of industrial equipment for a slightly secret project. Attached to what looks like a hunk of rusty metal to most was an octagonal "funnel" made of plywood and fibreglass.

The funnel has been the subject of much discussion lately which mostly boils down to "it's too good throw away" and yet it has been taking up space in an undisclosed workshop for some time now.

Enter one half baked idea:

I enjoy designing furniture with a rather raw industrial aesthetic out of scaffolding pipe and other ridiculously over engineered materials. See bad photos of a bunk bed and computer desk I built for my time as a student in Auckland.

Now I quite like Industrial light fittings.. So the only logical thing is to use this funnel for a light shade! Why a light shade? Well here's the inspiration.

The stereotypical Retro hanging lamp that you see in many minimalist apartments.

So the arm is going to be 40mm scaffolding pipe and the base is going to be more... Pipe...

The only part that is undecided is what kind of light source do I use and HOW MUCH POWER?

Some suggestions:
Low Pressure Sodium: Very yellow and very efficient with a decidedly streetlight aesthetic.
High Pressure Sodium: Better CRI and less yellow but a VERY "hemp" aesthetic.
Metal Halide: Better CRI again still "hemp" and expensive.
Mercury Vapour: Decidedly green tinge and cheap.

So what should it be? And how much power should it consume?

Hobby Motor Mount

James and I are teaching the Engineering Foundation course again this year and one of the projects we're going to be doing is making a steam powered electrical generator.

The generator will be based on the steam turbine car which the students built earlier in the course.

The steam turbine car kit is from the University of Kwazulu Natal, in standard form they scuttle up and down the corridors of our engineering department while running on meths... Much to the displeasure of the cleaners.

We're going to be using a small DC hobby motor as the generator. Now i wanted something elegant for mounting the motors that would be compatible with the perforated plastic mechanical construction system we have for the class.

20 minutes with Sketchup and I came up with this:

The part was subsequently printed and here are two clamping the motor complete with a 3d printed pulley.

New Conduit Clamp for the Rapman

For about a year now the Rapman has had a clamp holding the plastic conduit. The clamp was inserted into the original 10073 conduit mount plate. The plate is laser cut acrylic and on a recent trip to a secondary school I managed to smash it getting into the car.

I decided to design a part that took place of both the clamp and the mounting plate in one piece... 30 mins in google sketchup later and I had this:

Into the printer and 50 minutes later I installed the new part :) 

Time Lapse Panning System:

I'm shooting another video in the not too distant future which is going to feature a number of different time lapse scenes. After seeing a rather epic video by Jared Brandon I knew that some kind of motion system was needed:

Mt Ruapehu Timelapse from Jared Brandon Productions on Vimeo.

Staring blankly at the 3D Printer I had a brain wave: Sitting in the ceiling was my reflector telescope with a perfectly good equatorial mount... This mount allows the operator of the telescope to easily track a star or planet across the night sky as the earth rotates.

The brainwave involving the printer was to adapt the mount to take a DSLR camera for time lapses.

An hour with Google Sketchup and my vernier calipers I had a few parts drawn up.

The part on the right is an adapter plate the attaches a Manfrotto quick release adapter to the equatorial mount. The part on the left is a clamp for mounting a cordless drill motor (more on this later)

Then on to printing :-)

The adapter plate:

And the motor clamp:

Measure 200000000 times, draw, redraw and redraw meant that the parts bolted together without a hitch.

Mount with legs attached and a camera attached to the QR adapter:

So are you wondering what the cordless drill motor is for yet? The whole idea behind this system is that the camera can be moved a fraction of a degree in pan and or tilt between each of the hundreds of exposures required to make up a decent time lapse. Now I don't know about other photographers or engineers out there but I'm not doing that manually!

Enter the cordless drill motor: With the chuck it mounts onto the driveshaft of the pan head very easily. The clamp simply serves to take some of the motor's weight and to stop it from turning.

A test of the head with the camera in video mode:

Control electronics are in the works, likely to be based on the Arduino platform... Stay Tuned :-)

Engineering a Music Video?

So despite being an electrical engineer and working full time at IRL and WelTec I rather enjoy playing in the entertainment industry:
Some past work includes Sleepeater and Walk Through Fire there are also a few other projects that I'm not that keen on talking about in a forum as public as this...

Anyways all these projects have involved me doing roles like special effects so I've never "directed" anything... Until now...

Enter Alphashift a band of guys who I know through work. In short they make music and I like messing about with cameras... So it was only natural to make a music video with them.

Here is where the "Music video for a band" stereotypes finish... You may think it's a little strange that an electrical engineer is directing a music video? Well things are going to get stranger still when I introduce some of the cast and crew:

Jonathan Otto: Director of Photography and Mechatronics Engineering student.
Mike Williams: Camera Operator, Brains and Automation Engineer.
Fred Glover: Bassist for Alphashift and Software Engineering student.
Innes Hutchison: Drummer for Alphashift and Civil Engineer.
Trevor Molloy: Guitarist for Alphashift and Automation Engineer.

Yes a slightly unusual group of people to be shooting a music video :) And here's the final result:

Repairing the RapMan 3D printer:

So the RapMan started to misbehave a while ago... The parts being printed weren't very strong and the layers would separate with very little force.

With a bit of sleuthing I worked out the the 200k Ohm thermistor in the extruder nozzle was drifting out of tolerance in a big way.

A quick email off to BFB and Michael kindly sent me out four spare thermistors.

Let the rebuilding begin!

The extruder heater, nozzle and thermistor assembly are all held together by fire cement, this necessitated a little exhumation of the nozzle :)

I soaked the nozzle in hot water to soften the fire cement (I more than once very nearly took a swig of cementy water thinking it was coffee...)

After a little persuasion the cement was removed allowing the replacement of the thermistor :)

The printer has just this minute successfully completed a test print :D More to come.

Replacing the Magic Smoke

So I've been doing a lot of work with the Rapman Printer lately. The present mission is to print a set of spare parts for a complete machine. Said parts are going to be assembled into a replicating mashup of a machine, stay tuned on that one :)

The upshot of it is that running the printer for extended periods caused a very well documented manufacturing fault in the electronics to rear it's head... There is no real protection for the ADC of the microcontroller reading the thermistor in the extruder.

Now when you have:
A machine made of insulating plastic brackets supporting a metal frame.
Hot molten plastic flowing through a conductive extruder nozzle.
And a fan continuously blowing air over the nozzle and work piece.

The above is a very good recipe for static electricity :) Whenever the relative humidity droppled below about 50% the machine would start crashing randomly. Throwing away three or four hours worth of printing was starting to get a little frustrating so I went in search of answers.

The recommended fix in the BFB forums is to run a steam humidifier next to the machine. I did try this and yes it worked...

However I have some fundamental engineering, ethical and financial issues with this as a fix:
The machine as it is uses about 50W and the humidifier uses another 250W, Ethically I have an issue with increasing the power consumption of a machine by 6x just because of a design flaw. From an engineering point of view a lot of humidity around electronics and bearing surfaces is never good. And it makes the room damp in winter!

So I started poking the machine with  combination of zener diodes, capacitors and LEDs when something went pop. A wayward multimeter probe let the smoke out of the $25 extruder motor driver IC, bother. (feel free to insert non PC substitutions for bother which I may or may not have used at the time)

Above is the smoked 28pin T-SOP device sitting on my fingertip, it was removed with the judicious application of hot air from my SMD rework station.
The new IC was attached using solder paste, said rework station and a little swearing.

With the machine working again, my attention turned back to fixing the crashes.

On the right is a rather mediocre hand drawn circuit diagram on what I came up with to solve the problem.

The 220nF capacitor serves to soak up any high frequency noise and spikes while the 3.3V zener copes with overvoltages. The LED serves to increase the forward voltage and leakage resistance of the zener to a level that doesn't affect the temperature measurement accuracy. It also flashes whenever there is a decent static discharge to the thermistor :)

So far the machine has run for about 30 hours without any signs of crashing or glitches, long may it last.

Again on the right are the zener, capacitor and led soldered somewhat crudely to the extruder connector for now. Also of note in the picture, the extruder motor driver IC.