Making it real

Makerbots at the Maker Meetup

I’m involved with the burgeoning Wellington Maker Group, a collective of people that like to create something from nothing in their spare time. As part of this group I’ve taken a 1/20th shareholding in our very own Makerbot Thing-o-matic and since I was part of the core group that assembled it, I’ve been lucky to get some early build time on it. At first I got involved with the whole thing just because it’s totally cool. I had no idea what I wanted to build. In the end I needn’t have worried as mother necessity gave birth to my invention.

The Logitech G25 as it comes

Me, my brother, my brother-in-law and an old co-driver of mine all own the ubiquitous Logitech G25 to add realism to the online racing simulator we all play, rFactor. The G25 is a great wheel. It provides dynamic feedback which enhances game play well beyond any other controller on the market. The only downside, in the long run, is the wheel is a bit small. As such, I thought it’d be cool to get hold of a cheap aftermarket wheel and replace the original. Fortune had it I managed to pick up a used Momo racing wheel off of TradeMe for a mere $30 the same week the makerbot was built. Here was my project, to make it fit!

The size difference is noticeable!

The standard name for a steering wheel adaptor is a boss, so what I was wanting to make was a Momo to G25 boss. The first step was to grab the parts, my vernier and open up Sketchup. It didn’t take long to get  the basics together. The important things to note are that you only get once chance in Sketchup to change the accuracy of circles. You can see in the model image that the resolution of the circle is very low. More accurately it’s a 24 sided polygon. Turns out Sketchup can’t do true circles, just very high resolution polygons, so when you create a circle that is going to be large enough to have the shape noticeable, up the number of sides, 100+ would do nicely for what I was building but 24 doesn’t bother me at all.

Resplendent in lime green, the finished model. Note the 24 side polygon

Once the sketch was complete, I needed to get it into STL format. For that there is a SketchUp Plugin. You want to choose MM and then STL. Additionally, you will need to do a ctrl-A to select all (or equivalent in Mac or Linux) to select all of your object before running the export. You will now have an STL file which you will need to import into ReplicatorG.

At first I couldn’t work out why nothing showed up when I used the import function in ReplicatorG. The reason was because I hadn’t built the model around the origin in SketchUp, I had it floating out in space. To fix this use the ReplicatorG menu option of Move>Put on platform which should center your object. If everything has gone well, your item should be rendered in all its glory in the 3D box provided. You have some more options to flip it around if you’re worried about over hangs etc but for me now, everything was perfect.

My lovely model all golden in the ReplicatG screen

The next step is to make some gcode. This is the machine language of CNC and what the makerbot thing-o-matic also speaks. Here is where, for me, some of the “magic” or mis-understood parts of the printing process come in. Bruce Hoult, another founding member of the WMG Makerbot group, had done the primary configuration of the bot, so I didn’t really have any problems with the print quality, as he had mostly sorted it. In fact he sent me a file that I needed to import that would enable all the correct options for the gcode rendering. Because each bot can be and will be configured differently, you need to render the gcode, or the bot instructions, specifically for your machine. You can think of the STL file as the common point of reference and the gcode as the specific instructions for your bot. With the appropriate settings I ran the gcode generation. It took a few minutes.

Here's the gCode after generation as found in the gCode tab. Note the com port error as the makerbot was not attached to my computer at the time of screen capture

At this point, you are now technically ready to print. It took me about 4 false starts to get a print started properly. Seems there is no pre-warm code in the gcode I generated so I had to manually warm the extruder nozzle up myself using the control panel available in the top tool bar in ReplicatG. Our bot is set to extrude coloured PLA at 195C. After hitting run, the machine centered itself and began the predicted 2hrs30 print job. I couldn’t let it run completely unattended as I was having snagging issues from the PLA spool Bruce had printed but other that I had no problems at all.

It really was quite amazing to hold, what only a few hours earlier had simply been a concept, in my hands and the scary thing is that the next generation will take this ability for granted. Every school will have a 3D printer by the end of this decade and no doubt many homes too. For such a seemingly crude device (stacking hot plastic?!) the boss was strong, rigid and accurate.

The final part with all fittings shown against my vernier for sizing

Assembly was simple, I embedded the nuts into the designed recesses after cleaning them slightly with a craft knife (overhangs are the weakness of the extruder design). I then placed it on the G25 hub and used the original screws to attach it. The heads disappeared beautifully into the countersunk holes. Next I attached the wheel with my inch long screws which grabbed the nuts perfectly. No overhang through the boss at all means the design is very clean. I’d even managed to get the horn button recess correct and this slipped straight into the centre to give what I feel is a remarkably professional finish.

Here's the G25 with the standard wheel removed

Here's the final mod including the horn button (not yet hooked up)

To top it off, the whole project was a success. The wheel feels great in the simulator and adds further realism to a great game. As with all successful projects they spur you on to the next so I’m hoping the sim will be getting some pedal and seat upgrades! But for now, I’m satisfied….

Quick lap of Monaco on the new rig. Filthy desk and offset monitor to be corrected

Whilst there potentially was some ability to make some money out of the project I decided since I’d had so much help in getting it up and running that I’d share the output. As such you can find my Momo to G25 boss on thingiverse and can print it out or play with the design to your heart’s content. Enjoy!

Posted in motor racing | Tagged , , | 3 Comments

House model update

I’ve not had as much time as I would’ve liked but I’m still plugging away with my house modelling in SketchUp. The timber framing for the lower floor is almost complete. It’s interesting how many measurements I’ve managed to stuff up without realising it. It’s not until you start intersecting things that some of the mistakes become obvious. Additionally, because SketchUp makes it so easy to reference off of other points, a mistake can be quickly exaserbated.

Ground floor framing almost complete. It's not a prison, I just haven't broken the studs for windows yet

Things left to do to sort out the ground floor:

  1. Break the window studs
  2. Lower the brick fascade
  3. Add the decking joists (they’ll fill in the gap of the first floor timbers)
  4. Fill the joists with nogs
  5. Get the beam height right for once! (the joists sit on it, not go through it)
Posted in Nothing | Tagged | 2 Comments

Subsonic couch

You heard it right, a subsonic couch. As in inaudible. It shakes, rattles and rolls.

Two subsonic modules, a 2 x 50 Watt stereo amp and an active crossover make this couch anything but ordinary.

This a view of the bottom of the couch where you see the two subsonic actuators bolted to the frame. Subsonic actuators are effectively speakers with the cone replaced with a weight. They don’t need to drive air as the human ear can’t hear frequencies as low as what these operate at. They’re built to drive from about 5-200 Hz (guesstimate) and whilst having a voicecoil equivalent, they’re actually just moving a weight. These two actuators were sourced from Jaycar in NZ when they bought a shipment of Aura Interactors a decade or so back. They aren’t a stocked item anymore.

The amplifier is a Dick Smith Electronics kit and is overpowered for this operation in being 2 x 50W. I believe the original Aura Interactor amplifier packs were in the region of 5-15W. The large torodial transformer gives you an idea of the power that the amplifier is rated for.  I purchased this kit back when DSE used to be an electronics company which it sadly no longer is. A rough equivalent would be 2 of these Jaycar kits.

The other box you can see is the Dick Smith Electronics active crossover kit (K5404?). It contains volume and frequency cut off options and allows me to adjust the couch in line with the volume output of the amp. Ideally you’re connecting this to a sub-woofer line output so that the amplifier adjustments are effected in the couch too. The active crossover ensures that we’re not trying to make the subsonic actuators do what they weren’t made to do ie move at frequencies above 200Hz.

In operation, the couch adds punch to your movies that even the best sub-woofers would struggle with without having to worry about the neighbours ringing noise control. Explosions in movies become an interactive experience!

Unfortunately this photo was taken as I was taking the set-up out of the couch. After I moved to Wellington the couch sat unloved in my sisters flat for a couple of years. Little did she or her family realise they were sitting on probably one of the only 100W subsonic couches in New Zealand. They just weren’t into movies in the same way I was… As I had no easy way of getting it down to Wellington and no substitute couch to put it in, it lay unutilised. On my latest trip up north I found out they were wanting to dispose of the couch so I’ve grabbed all of my handy work and it is now planned to be added to my forthcoming rFactor simulator. If you’ve ever sat in a real V8, you’ll know that most simulators can’t recreate the rumble as you start it up or floor it. With 100W of subsonic actuator bolted to a bucket seat. My simulator will…

Posted in Nothing | 2 Comments

Sketchup love

I’ve been painting the shelves of the bookshelf unit I built a few months back. While the paint was drying it got me to thinking that it’d be a great practice model in SketchUp. Incredibly, 30 mins later this is what I had. I say incredibly because I only really started using SketchUp this week. I know a pro could do it in under 5 mins but this is the 3rd CAD product I’ve ever used and the only one I’ve ever got any output from.

I modelled this office bookshelf in less then 30 mins

Here is my actual office cabinet.

This one took me a lot longer to put together! Ignore the mess, it's spring cleaning weekend.

What an incredible tool. I’ve just looked up photo-renderers and they’re looking very affordable starting at around US$180 commercial.

Posted in Nothing | Tagged | Leave a comment

McLaren M22

My father and I went to the New Zealand Grand Prix meet held at the  Manfeild circuit outside Palmerston North last weekend. It was a great day with the one make Suzukis putting on some good racing, the NZV8s putting on some great racing, the American Muscle cars putting on some of the best entertainment but the real show stopper for me was the lunch time entertainment; the McLaren M22.

Check out that airscoop

More or less what the driver sees when sitting in a McLaren M22

There are four more photos on Flickr of this car and these two at different sizes.

Here’s the video I took of Craig Baird’s laps. I wish the commentators had talked a little less but at least they did stop themselves for one run down the straight. Sounds great on my Yamaha amp all cranked up.

Posted in motor racing | Tagged , , | Leave a comment

SketchUp progress

I’ve been modeling my house in SketchUp. This is how far I’ve got so far and it’s mostly dimensionally accurate.

My early progress in learning SketchUp has got me this far.

I’ve found a pretty awesome channel on YouTube called The SketchUp Show. I’ve seen their lattern demo and think I should give that a try as I’m pretty sure I’m missing some of the more basic skills that they showed in that…. The demos make it look really easy so obviously I need some practice and potentially a mouse. My trackpad doesn’t seem to cut it.

Posted in Nothing | Tagged | Leave a comment

Getting started with Sketchup – again

After a false start last year I found some renewed enthusiasm for getting started again with SketchUp after seeing a presentation at the Wellington Makers group by the new head of Ponoko‘s 3D production Rich Borrett. At the meetup he showed how we could make a 3D item from 2D parts as shown in the first image on the left on Ponoko’s blog article on the meetup. You can simply model the item in 3D and the apply a plugin which will turn it into the 2D parts. This sort of thing is ideal for making RC planes although the laser time might be prohibitive in terms of costs. Doing this is something on my “to investigate list”. If it is too expensive, then I’ll just have to finish my own 3D CNC router which is about 15% complete after 5 years since starting.

With SketchUp I wanted to stretch my interest in architecture and Rich’s demo gave my the inspiration to get going with it again. There really is something magical about seeing someone achieve something in front of your eyes as opposed to trying to teach yourself. So, I’ve started modelling my house so that I can plan the renovations we want to do as well as learning some skills I can apply across all my projects. 3D is where it’s at and there is no better time to get involved. SketchUp has made it accessible.

Posted in Nothing | Tagged , | Leave a comment

ERB569 stolen by a stalker

Some scumbag has stalked my mum from her car into Pak’n’Save supermaket Royal Oak, Auckland, New Zealand. They have then waited for an opportune time to steal her handbag from the bottom of the shopping trolley and then stolen her car.

The car is a bright red 1999 Volkswagen Golf and looks like this:

Our car, identical to this, was stolen from Royal Oak, Auckland 26th January 2011

Our car, identical to this, was stolen from Royal Oak, Auckland 26th January 2011

If you see it then please call the Police to report its location. It has two child seats in the back with lots of childrens toys and books belonging to her grandchildren.

If you know who stole it, then you should know that they prey on retired women, stalking them from their cars and trailing them around supermarkets so they can take advantage of them. That is psychologically dangerous behaviour and you should be very scared.

Posted in Nothing | Leave a comment

Cap 232 initial fight report

Finally had a chance last year to give the Cap 232 its maiden. It was a very nervous time as the model didn’t have a manual. This meant I had no idea if:

  1. The servos were strong enough
  2. The all up weight was ok
  3. The engine selection was appropriate
  4. The thrust angle was correct
  5. And most importantly the throws were within a useful range

Well, it was a bit of a disaster all round. I went to one local park and had been running a few taxis trying to find some courage. Then a whole school of kids started to walk past. Literally about 400 children. So I gave up on that one. It’s one thing to destroy a new model, it’s another to destroy it in front of a cheering crowd.

I went to my normal spot later in the day and decided to have a go. I powered her up after a range test and hand launched. It barely lifted and then sort of slumped nose up into the grass a few meters away (much like jets drop off the end of a carrier when they haven’t quite reached flight speed). This was fail number one. I’ve been flying a foamy so long I’d forgotten that balsa planes need a good solid launch. My foamy will literally pull itself out of my hands and fly off. The undercarriage had ripped off but the plane was still essentially complete so I decided to persevere.

Second launch my old skills came back and I gave it a good solid heave. She took to the air just fine and started slowly climbing away. My nerves were very fried and getting more sizzled as I tried to trim anything near level flight into it. Unfortunately I’d gone super wrong on the throws. I’d figured the surfaces were pretty small so throws slightly less than the foamy would be reasonable. Wrong. The plane was all over the place and each slight correction was throwing the poor thing all over the sky. Nose went up, right wing down and it disappeared off behind a bank. I cut the power and used my old slope skill of cranking full up elevator when  a plane goes out of sight in a bid to stall it to the ground. I’d pretty much given up on it by then however. From that height and especially over the bank, it should be a pile of balsa by now. I turned the transmitter off and headed across the field to collect the remains.

To my utter amazement there it was sitting with no further damage on a stand of long grass! It looked like it had stalled back into the bank and the grass had caught the rest, what a stroke of luck! About now I was thinking I should give up but I decided that since I’d already written the plane off in my mind, I now effectively had a free plane (can’t fault that logic). So I got into the plane set-up on the transmitter and dialed the throws down by half and put in 50% exponential. In hindsight, exponential is really exactly what I should’ve put in from the start but was something I’d never played with before. Lesson learnt.

Third time was a charm. Solid hand launch and away she flew. Still very twitchy especially on ailerons but off she flew. I got a modicum of flat trim in and started on a few circuits. I then backed off full power and suddenly she started to climb (as best as I can recall). This means the thrust on the engine is all wrong (full power is dragging the plane down) and this isn’t something I could fix on the field. With my nerves pretty fried I decided to bring it in to land. I put her far out to my left and cut the gas. Mistake number 4(?) for the day was forgetting how much momentum balsa planes have over foamies. The biggest problem I have with landing my foamy is to get it close enough once the battery is gone as its glide slope is about 50% on no power. However this thing, damn, it just kept going, slicing through the air exactly as it was designed to do. Fortunately there was plenty of room but I overshot the nice grass I’d planned on landing in by about 10 meters. There was no real further damage to plane or ego and so I packed up and went home.

I’ve since managed to realign the motor. I used a long ruler against the elevator stab to get some idea and then eyed it up with the chord of the wing. For some reason the built in motor mount has about minus 5degrees. I hope I’ve not gone too far the other way…

Original motor mount angle versus new angle, zero to wings

I haven’t decided if I’m game to glue the undercarriage back in yet but I think I probably should. I am looking forward to flying it again though! Just need this weather to sort itself out and for a let up in work…

Posted in RC planes | Leave a comment

13 virtues

Temperance: Eat not to dullness and drink not to elevation.

Silence: Speak not but what may benefit others or yourself. Avoid trifling conversation.

Order: Let all your things have their places. Let each part of your business have its time.

Resolution: Resolve to perform what you ought. Perform without fail what you resolve.

Frugality: Make no expense but to do good to others or yourself: i.e. Waste nothing.

Industry: Lose no time. Be always employed in something useful. Cut off all unnecessary actions.

Sincerity: Use no hurtful deceit. Think innocently and justly; and, if you speak, speak accordingly.

Justice: Wrong none, by doing injuries or omitting the benefits that are your duty.

Moderation: Avoid extremes. Forebear resenting injuries so much as you think they deserve.

Cleanliness: Tolerate no uncleanness in body, clothes or habitation.

Chastity: Rarely use venery but for health or offspring; Never to dullness, weakness, or the injury of your own or another’s peace or reputation.

Tranquility: Be not disturbed at trifles, or at accidents common or unavoidable.

Humility: Imitate Jesus and Socrates.

Benjamin Franklin‘s thirteen virtues, 1726 (age 20)

I just found these. Aged 20. Incredible. Destined for greatness at an early age no doubt.

Posted in Nothing | Leave a comment