[Blog]
>> Terran Rover: steering success!
You know that moment that comes while you're in the process of modifying something, and you put the cutters around the piece of plastic or wire or whatever, and just before you squeeze the handle there's a flash of "anticipatory buyers remorse" where you realise you're about to do something irreversible? No? Oh well, maybe it's only me. The original steering mechanism used a steering arm that was quite long with a cam on the servo to move it, providing significant mechanical advantage. The new servo I've put in though is incredibly powerful and doesn't need any extra leverage so I cut up a new servo horn and the original steering control arm and combined them into a custom horn that will move the steering rods directly. The problem is that the forces involved are rather large and the pieces I had to join are rather tiny so I was worried that they wouldn't hang together. In the end I clamped them together in the right place and cross-drilled with a 0.95mm PCB drill, then screwed them together with the smallest bolts you've ever seen in your life:
I put in two bolts in each direction then snipped off the excess length with wire cutters. They are seriously small: think about the diameter of a dressmaker's pin, and even that's bigger than one of these. I then covered the bolt ends with Araldite, which I also put all around the joint edges. I would have liked to get it between the plates but it wasn't possible to do that and still bolt it.
This morning before work I attached the horn to the servo and fitted the steering rods. This shows the steering assembly upside-down before the bottom cover was fitted:
Then with the cover fitted it all looks exactly like it did from the factory, except that now it's using a standard servo that I can control directly from a PWM output of an Arduino.
I plugged it in and ran a loop on the Arduino to swing the steering from side to side. Success!
Next I need to reassemble the chassis with the steering and I'll be ready to start fitting sensors.
>> Terran Rover: steering control
As predicted I got annoyed at trying to reverse engineer the existing oddball steering servo, so I decided to rip it out and put in something standard instead. A trip to Jaycar scored me a 13Kg/cm servo which *almost* fit in place of the original, but not quite. The original servo was a jam-fit into the space and then held in place with hot-glue, so to get the new servo to fit the first thing I had to do was modify it to bring the wiring out the side instead of the end:
Then it still wouldn't sit far enough down because of the mounting tabs, so I cut a slot into the back of the steering sub-chassis to let it sit in the right place:
In that pic the sub-chassis is upside down. I still need to fix the servo in place and reassemble it all, and I have to make a custom servo horn to attach the steering rods. Once that's done it'll be a simple matter of plugging it into an Arduino for direct control.>> Massive web growth
The February Netcraft Web Server Survey just came out, and the figures are rather dumbfounding. Netcraft perform an automated survey each month in an attempt to create a definitive list of every single website in existence, and along the way they collect a bunch of data about what is the most popular web server software, how many sites use SSL certificates, all that sort of thing. The Feb survey shows a big spike due to the addition of about 20 million sites hosted by QZHTTP, a big Chinese hosting provider. Added to the more "normal" growth of the web that means there were 30 million new websites added between January and February this year! That's a million new sites per day. Or 41,000 sites per hour. Or 700 sites per minute. 12 sites per second! Pretty crazy. Even if you remove the unusual spike caused by QZHTTP it's still amazing growth: nearly 14,000 new sites created every hour, not counting the massive growth in China. I don't think the web has quite run out of steam yet.
>> Memories of a previous life
Cleaning up tonight I came across some crusty old documents hiding in a drawer, including a few expired driving licences and this relic:
So I cut them up and chucked them in the bin, then a few seconds later fished the security licence back out. It represents such a weird (and formative) piece of my life that I thought it was worth taking a photo.
Not many people who know me from the software world are aware that I spent some time around '94 and '95 working as a bouncer. I worked for New Breed Security for a while and got to meet the who's who of the entertainment world at the time, as well as a bunch of famous sportsmen and women. It was a bizarre lifestyle of getting up at lunchtime, having a few hours of free time and heading off to work in the late afternoon or mid evening, then working all through the night at a job that was 95% pure boredom, 4% pure entertainment, and 1% pure terror. A couple of my old school mates ended up working with me for a while and a couple of weeks ago when I was in Sydney for Brad's wedding I was reminiscing with him and Phil about some of the crazy stuff that happened, like the night Phil and I were working at the Conti in Sorrento with just one other security guy and expecting a quiet night with some of the locals when a football team from up the peninsula came in to spend a night boozing up after losing a big game. It didn't take long before the locals and the players clashed, and it ended up in an all-in brawl involving dozens of people and just the three of us security guys helplessly trying to restore order. I have a lasting memory of seeing Phil's back as he headed toward the exit with one footy player in a head lock on each side - which would have been fine except that his feet weren't touching the floor!
Things got rough for a while and a minor amount of blood was spilled, but with the assistance of some of the locals and other random staff it all got sorted out and the players headed off to their hotel rooms to sleep off their drinks. Hotel rooms that, unluckily for them, happened to be in the Conti itself! The police attended and spent a while taking statements from us, then went with the hotel manager to drag the players back out of bed. Bad luck for them, they should have left while they had the chance.
A couple of hours later I was heading for home when I was pulled over by a police car. I got out and walked back to the cop car with my wallet out and was in the process of removing my licence when I realised that the policewoman who had pulled me over was the same one that had taken my statement earlier in the evening about the brawl. As soon as she saw it was me she just said "Oh, it's you, never mind" and waved me back to my car.
Strange, strange times. In a way it's what directed me to where I am now though, because it was through doing event registrations and security that I ended up starting Mission Internet, which is what became IVT. In 1994 I created an online registration system for the Bicycle Industry Trade Show, using a FileMaker Pro database and some really schlonky Applescript and either the WebStar or Quid Pro Quo webserver (I can't recall which I was using at the time). The system generated registration passes with barcodes, and I also wrote some logging software to run on an Apple Newton so trade show delegates could be scanned on entry and the entry time logged. It seems commonplace now, but doing online event registrations in 1994 was pretty much living in Jetsonville. And now, 15 years later, I'm still doing pretty much the same thing.
And you know what one of our development projects is right now at IVT?
Another event registration / management system. Luckily this time I don't have to write a single line of code though!>> Semi-autonomous rover project
Something I've always wanted to build is a little rover, something that can act partly autonomously under high-level direction. The general idea is to be able to just give it a destination and leave it to get there by itself, kinda like a micro-size DARPA Challenge. And now with the Arduino book just getting underway I have the perfect excuse to do it. "Yes honey, I'm hacking a remote control car and putting an Arduino in it. No, I'm not doing it for fun. This is something I have to do. It's just work for the book. Seriously!" My objectives are: 1. Put motor and steering under Arduino control 2. Add obstacle sensors and collision sensors (ultrasonic and physical) 3. Add GPS so it can figure out where it is 4. Add a payload of some kind like an Arduino-controlled camera 5. The hard bit: write some code to have it attempt to get to a specified GPS location without running into anything big, falling off a cliff, or driving into a drain. I just happened to have this old RC car hanging around from years ago when I'd bought it to muck around with building an automatic lawn mower:
After a couple of hours of unscrewing, cutting, de-soldering, and general hacking I had it reduced to the basic chassis with just the battery pack, drive motor, steering assembly, and suspension still intact. A bit of mucking around with an IRF540 MOSFET and this is what it looks like, with the main drive motor under fully proportional speed control using PWM from the Arduino to control the MOSFET:
Obviously the drive circuit needs to be transferred to a PCB, but right now I'm just getting it working. Next I need to control the steering servo, but it seems to be a bit of a bizarro-world design that relied on the now-defunct radio receiver for the logic to make it seek to a specific position. I can control the motor, but I'm getting very odd positioning feedback so unless I can figure out how it works I may have to rip it out and replace it with a standard unit that I can control directly off the Arduino using PWM. It's actually glued into the steering assembly so that wouldn't be trivial, but it may be easier than spending hours trying to figure out this weird design.>> Behind the scenes on Foxtel's The Phone
Well, the secret is out now so at last I can reveal some of the things I got up to late last year.
As part of my mission to get the SuperHouse TV show going I've been talking to a lot of people in show biz and pumping them for advice and contacts, and along the way I was asked to help out as Technical Supervisor for a new reality-TV show which started its first season on Fox8 a few weeks ago.
My role included designing and building gadgets and writing software for use by contestants in the show, which is filmed to look like a cross between The Amazing Race and The Bourne Identity. The contestants are real and doing their best to figure out what's going on, but everything that happens around them is being driven from behind the scenes and because it's filmed out in the real world rather than on-set it's quite unpredictable. The contestants interact with actors during each episode but also with random members of the public so from moment to moment the production team really didn't know what was about to happen. It was quite a bizarre experience!
So there were no chances at second takes: things had to just work, particularly the gadgets and software. Of course I used all sweet FOSS technologies, so the gadgets were built with MySQL, Arduino boards, Apache, PHP, and random other Open Source stuff.
Episode 4 was filmed in late September in Tasmania so on Friday 26th I bolted out of the office a few minutes early and grabbed some gear from home before heading off to the airport for a flight to Hobart, where I worked in my hotel room until about 3am getting some software finished off and then grabbing 3 hours sleep and getting up at 6am to meet with the Director prior to the pre-shoot briefing. Then it was off to Salamanca Market with my backpack full of gear to use during the day, including 3 Macbook Airs plus a bunch of custom hardware that you see in the show. It was kinda weird walking around the crowded market with a backpack containing gear worth more than some new cars!
What I found *really* interesting about the show is what goes on behind the scenes. Here's a classic example using a series of photos I took at the final location for the day, starting with just what ended up on TV and then going progressively broader. Let's start with the talent, Justin and Madeleine (Justin Melvey is rather famous in the US after doing 4 years on Days Of Our Lives, but locals may remember him better from Home And Away):
What you see on TV is Justin and Madeleine alone at a campsite. What you don't see is that a few seconds before they were flanked by a producer, a director, and a cameraman:
Then swing the camera around a bit and suddenly it's starting to look crowded, with all these people just out of camera shot:
Think that's busy? Once the contestants had been through and done their thing and the crew were striking the location and loading everything into the vehicles, I took a shot of the carpark. Every one of these people is involved in the show, and that's not even everyone at that particular location (there were a couple of other cars out of my field of view):
I count 22 people in that photo.
So I made a point of taking lots of pics of the crew doing their thing during the day. When you watch a reality TV show with contestants out doing things in the real world you may only see a few people on screen but what you don't see is this:
Or this:
In that last pic we were following and filming the contestants in another car traveling through Hobart while a helicopter hovered above to get aerial footage. The van we were in had a big cross on the roof so the helicopter could find it easily in traffic, and we had to stay some distance back from the target vehicle so we'd be out of shot in the aerial footage. There were two choppers used during the day, one as a camera platform and the other for use in the show itself.
The challenging thing about making a show like this, of course, is that the contestants aren't actors. They're not following a script and they're unpredictable in where they go and what they do. They have to complete a series of challenges that take place at different locations over the course of the day, and the production team just have to try to keep up: if they do something significant and there's nobody there to film it, too bad. The moment is gone, and they're on to the next thing with no second takes.
Totally different to filming scripted scenes with nobody but actors in front of the camera doing what the director tells them!
Another "behind the scenes" shot, this time Justin waiting on a motorbike just prior to a sequence at Salamanca Market while a camera assistant rigs a camera on top of a parking sign assisted by a runner, a cameraman stands on the other side of the ute, and a sound guy waits on the footpath:
And finally this is one of the art department guys bringing a metal briefcase to the campsite scene at the end of the episode:
Hmm, a briefcase? Camping? Why would you need to take a briefcase camping?
The obvious answer, of course, is lots of money:
Yes, that's real money.
Yawn. Another boring weekend.
>> Got an interesting Arduino project?
We're in the brain-storming phase of working up a list of projects to feature in the proposed Arduino book and looking for as many suggestions as possible for things to feature. We want to have a wide range of projects from simple to complex, demonstrating a wide variety of techniques and interfacing with lots of different systems. We already have things on the list related to robotics, automotive systems, home automation, and other gadgets, but we need more, more, more! I know there are a bunch of people out there who have done some very cool stuff with Arduino boards (I'm looking at you, noisymime!) so if you have something you've built or even just an unimplemented idea please drop me an email.
>> Arduino book in the works
Well, after going through the whole process of working up a plan for a second edition of Ubuntu Hacks and lining up all the contributors it was given the axe by O'Reilly. That sucks, because I was looking forward to doing an update. I've had lots of people ask me when the next edition would be coming out so it's disappointing to tell them it's not going to happen after all, despite the first edition being O'Reilly's biggest selling Linux book. But then just after LCA I received an inquiry from APress totally out of the blue, asking if I'd like to write a book about Arduino projects. Hmmm, let me think. (3.14159 milliseconds pass) YES! Pick me! Pick me! I'm working on dragging Hugh into the adventure and it should be a blast. The general plan is to target a medium to advanced audience with a broad range of projects demonstrating as many techniques as possible, so there's probably going to be stuff about home automation, virtual reality integration, automotive projects, kinetic art, wearable computing, robotics, remote control vehicles, custom Arduino boards, and anything else we can think of. This is going to be *so* much fun!
[ Back to top ]
