Freesteel Blog » 2016 » March

Tuesday, March 29th, 2016 at 9:28 am - - Flightlogger, Hang-glide

It happened towards the end of the flight before last when my wings became my own, and I just wasn’t thinking about it any more. I stopped having those intervals where I lose concentration and fall out of the sky because there was no concentration to lose. It was all about the feeling.

Above the town of Teba watching the cars scooting along the grid of streets like busy beetles in a rotten log

Low on same rocky hill just after take-off where I struggled to survive for some minutes before I found a bubble of rising air

If you need to learn hang-glide, there’s a English school down here called Lejair where you could get it all done in two weeks (instead of the average two years of weekends back in England) because the weather is better and they use tow trucks with gliders tethered above a trailer so you can learn how to fly it without having to run up and down the hill and learn how to steer in short difficult bursts. (If you have to ask why you need to learn hang-gliding, then you don’t need to.)

We were woken by all this nice birdsound. Then we spotted that it was from three tiny birdcages in the courtyard below and it seemed so cruel. Why can’t they use little speakers tuned to a radio channel that broadcasts live birdsound?

Got to go now. We’ve not had an off-day where I can devote 10 straight hours to coding the datalogger analysis or write any of it up. I have two interesting results to report. One being the delay on the GPS, and the second being the clean mathematical relationship between the turning circle and bank angle as measure.

Wednesday, March 23rd, 2016 at 6:16 pm - - Flightlogger

Final late blog of the day.

An end-to-end design in Kicad all by myself, which was then cut out beautifully on the triangle machine tool.



Soldering, laser cutting and 3D printing took up the following week, and it should now small enough to fit onto the glider without getting in the way.

(Tom’s trick of defining a virtual second side of the board which we don’t actually cut, but instead implement with jumper wires worked a treat.)


We’ve got the questionable barometer, GPS, humidity, 2 temperature sensors, wind meter and an absolute orientation sensor (at the top) all logging at high frequency to an SD card and with an OLED screen to show me what’s not working so I can fix it in time. The black slab at the bottom holds 4 AA cells.

First thing that got logged was my fridge over last night using a string of 5 temperature sensors left over from Housahedron days:


It’s the most boring high efficiency fridge in the world with a cooling cycle of four hours and, not surprisingly, different temperatures on each of the glass shelves.

I’m wondering if the new microbit device, of which a million will be distributed to children, has enough tech in it to use as a fridge logger. Everyone has a fridge. This would make an easy project for kids to log and upload the data of their make and model to a common place in order to find where the crappy fridges are. In the future they need to all be found and replaced, because they cost significant energy and CO2, but nobody knows since the electricity bills are aggregated for all appliances in one house and are mostly unknown.

For contrast, here’s an overnight log (interrupted at 4am in the morning for my host to get up and drive to London) of a fridge in Leeds using a different datalogger where the cycle is four times an hour:
I can’t explain the long hiccup at 3am where it skipped 3 cycles. Maybe there is a lot of information in that particular curve, such that the real way to find out about the quality of the fridge is to turn it completely off and measure how warm it gets overnight. Great idea. I can see a lot of kids getting into trouble over that one when the food is all spoiled. To which they can respond: “Hey look, it’s only the fridge. It’s not like I’ve done it to the whole planet.”

Wednesday, March 23rd, 2016 at 5:03 pm - - Machining

Continuing our coverage of Autodesk corporate chaos, we read this from the latest Autodesk Earnings Call:

Carl Bass (CEO): Yeah. I just wanted to say one thing…

The first thing is that I think a number of the 13D filers as well as some of the activist investors have raised legitimate concerns…. I think too much credit is being given to them and not enough credit is being given to our long-term investors, who have asked for a change in a constructive way…

Many of my problems with sort of some of the more activist investors is that their focus is extremely short-term and somewhat simplistic. They just ignore some of the complexities of running a business…

[M]y concern is people who like essentially want to turn Autodesk into Men’s Wearhouse. If you look, I don’t think any of the people who got involved in Men’s Wearhouse intentionally meant to do damage to the company. I don’t think they meant to screw it up, but I think they had some simplistic views and what troubles me is seeing those same views expressed about our business.

Actually I got one little funny story here. I looked at Men’s Wearhouse the other day and they changed the name of the company and the symbol and what I thought was interesting is changing the name makes it actually hard to track the price and how poorly it’s performed. But the symbol is a little bit of a telltale sign because if you just look at it, it’s spelled TURD, it’s actually TLRD, but it’s what it looks like, and it’s probably more like it.

Basically, the investors had declared a truce with the management which involves inserting three of their guys into the chain of corporate command, such as it is.

This is probably the first time in 30-odd years that these folks have had people not of their own choosing within the system. And chances are they’ll find the processes ludicrously informal and ineffective, as they appeared to me lower down.

Wednesday, March 23rd, 2016 at 1:28 pm - - Machining

I haven’t got much time for this blogging lark today.

Before this gets too stale, here are some quick notes on the polar drawing robots that we had running from steppers and servos motors using Machinekit and drivers scavenged from the CNC milling machine.

This got shown at Phrased&Confused acoustic festival, where one of them had to perform on stage and almost peeled the corner off the paper it was drawing on.


This was the state of the robot a couple of days before:

And this was at around 5am the night before:

The project management was on github under

Problems remained with the Z-axis communication and its operation on the gondola, as well as inadequate pen pressure on a vertical surface from an object hanging down next to the vertical surface. But we did learn a lot more about the CNC servo motor operation, and MachineKit on the BeagleboneGreen performed excellently.

We hope to set it up on the wall some place and continue development.

Wednesday, March 23rd, 2016 at 12:01 pm - - Uncategorized

Funny story. My mum the author has published a Gothic novel.

A Man of Genius

Here’s the book launch at Daunt Books:
I only recently got my copy as I had to buy it on the open market so that it made a difference to the sales. I’ve just lent the unabridged Audio CD to a friend who recognized the reader as being famous (Miriam Margolyes), which I didn’t.

I considered, but rejected, the idea of playing it on the drive down to Spain with three other hang-gliders in the car, so I’m lugging the hard back in my baggage.

Wednesday, March 23rd, 2016 at 11:19 am - - Kayak Dive

I really have been neglecting to blog. I’m going to bang out a few quick posts on this the day before my holiday.

Saturday 12 March involved a grumpy day paddling around Hilbre Island with a rather fuzzy camera.

This is the stone wall on the northwest corner of the island at high water:

The professor on the water had just gone on a 10 day trip to Japan to use up an academic travel budget, and at the same time busted a chunk out of the dwindling global carbon budget [podcast here]. You don’t want to see what the bailiffs do when they collect on an unpaid carbon debt. They’ll take your food.

I’ve been speculating about a specialization of my Question from Hell proposal where visiting professors who have just flown to give a lecture get routinely asked about their carbon budget (which they could have avoided by teleconferencing) as the first audience question from a young student. It will be rude and ungrateful to ask such questions of a visiting guest, and will embarrass everybody. The excuses are lame.

The top excuse will be: “We don’t have the equipment”.

If that one gets a lot of laughter, the second excuse will be: “Meeting in person makes a big difference”. To which I’d like to respond: “Where’s the research?”

There isn’t any.

I’d love to set up a controlled experiment where the person who doesn’t do the 10 day trip to Japan gets to take a 24 hour bus ride to a hotel opposite a Japanese takeaway in Dundee via Plymouth and is locked-in with the internet where his only communications portal for the next 120 hours is a telepresence robot parked in the corner of the lab in Japan. He is free to rove the corridors if he’s being ignored. Maybe one of the brighter students would take pity on the robot and take it home overnight for late night chat with bottle of sake, or even for a night tour round the city on a motorbike. I hear these VR goggles and hi-def cameras are pretty good these days.

The time duration exposure, the portability, and the lessening of inhibitions could easily mean that human bonds and interaction could be much enhanced compared to proceeding to these places as a meat embodiment that smells and needs to go to the toilet occasionally.

If this Questioning takes off I am expecting that university administrators, who can be blindingly stupid, commit to ban such questions, as you cannot ban something like this without actually telling people what it is you are banning.

PS. Cory Doctorow was burning up the planet ten years ago.

Monday, March 7th, 2016 at 12:12 pm - - Machining 1 Comment »

The less said and remembered about the fighting I’ve had over the past three weeks attempting to get this working the better.


Basically, the problem was eventually traced down to a faulty solder joint on the ground pin of the six channel open collector chip which created too much of a resistance to drain the 5V signal down to ground for the gecko drive to respond in the rare case where four 1-signals were emitted from the Machinekit controller at the same time. This happened only when two of the axes were moving with the direction pins high and two step signals went to the motors simultaneously. This resulted in travel in the Y-positive direction missing 1% of its pulses so that the cutting toolpath drifted ever so slightly in the Y-negative direction as cutting progressed, but there being no effect when you jogged the table or arm axes individually. Drove me nuts, as you can imagine.

It was a learning experience. If we can nail this bug, we can nail anything (we had to check through so many other problems which weren’t there to find it), but it set us back weeks of worry, pain, late nights and missing weekends

Quick edited movie with limited footage as I forgot to film a lot of the exciting bits (like the helix ramping) as was a bit too scared to think of it.