Neural networks talk

Monday was a busy evening in the end! Mat demonstrated a robot that he’s building (no details, it’s a secret!) for a competition at the end of the month, and took advantage of the concreted courtyard in the NSME. Adrian brough some Nanodes to show to the group, and I (Stephen) talked about neural networks, ably assisted by Nicholas. The slides are on the wiki. This was attended by some visitors from the Northants Linux User Group (mailing list here) who hopefully haven’t been permanently put off.

I investigated how to polish 3D printed stainless steel, and Alan tried another form of light-painting, where a long night exposure is taken, and the subjects are lit with a flash gun and many flashes. Pictures hopefully to follow.


We’ve not done anything with the mill regarding controlling it yet, and so we discussed that as well. The feeling was that we should continue the computer control of it, but only with the assistance of someone who could manufacture the brackets required. We will ask the NSME for assistance, rather than attempt it ourselves.

Next meet

The next meeting is on the 27th June.

CNC fun

On Monday we spent most of the evening trying to get EMC to work on a donated PC, and then with Martin’s stepper driver board. Alan did some good work persuading the rather picky realtime Linux distro to work at all, and then we set to work.

The board consists of a breakout board connected to the parallel port of a PC, which opto-isolates its inputs before amplifying them up a small amount to be used with stepper motor drivers. These drives generate quadrature output from two input signals, a step signal (or clock) and a direction voltage. The job of the PC is to directly step each motor, and the accuracy with which it can do this affects the maximum frequency of steps that it can generate.

This is a hard real-time task and so a Linux kernel is used that allows tasks to be prioritised above nearly all of the kernel tasks and drivers. This kernel will not work with binary graphics drivers, and quite a few other drivers that are incompatible with its priorities, hence the difficulty in setting up. Once this obstacle was overcome we traced the stepper control lines to the right pins of the parallel port (in Martin’s absence) and eventually puzzled out the power supply to run the stepper motors themselves, admittedly pretty slowly to be on the safe side.

In lieu of having a mill to connect them to, we found some software for playing tunes via gcode and soon we were graced with at least the higher parts of the Super Mario Bros theme, played about 4 octaves too low.

May Day

The NSME May Day re-opening is now 3.5 weeks away, on Monday 2nd May. As part of this we’re having a stall ourselves (wiki page for organising here) in the afternoon and in the evening, a BBQ and hack session focussing on glowing in the dark! Whatever you’re making on 2/5, make it glow, by any means you like.

Next meet

Next meet is on the 18th April and will feature Mat talking about his quadcopter, how he built it, and how he controls it. This is also the only meet to test any contraptions for display or use at the NSME open day, so make the most of it!

October meet writeup

Firstly, apologies for the delay in writeup; six days after is a bit late. I would blame illness if it had started before Thursday! We met in the Malt Shovel on Tuesday as normal and planned a number of events.

Pinball evening

The pinball evening at Adrian’s house will take place on Saturday 27th November, and will start from 2pm, with an aim to eat at a local pub from 7pm. Exact location details to be announced. If you like pinball and especially if you’ve not seen the amazing insides of one, come along!

Robot competition

As already announced, Martin is organising a competition for NortHACKton to create a giant cardboard robot based on a winning submission. See the launch post and his examples.


We’re going to have another visit to the Northampton Society of Model Engineers on Tuesday 2nd November, kindly organised by Martin.

Projects to submit for Maker Faire 2011

We set out to choose a group project to make for the Maker Faire, but finally we chose two smaller projects. This has the advantage that we can highlight projects that we will definitely have built by March, but can also bring other examples of the things members have made. We’d also like to bring our giant robot if there’s room for it, but we don’t know what space restrictions we might have.

Guy is organising a life-size game of "Operation", and is currently planning this on the wiki. A hospital-theme and a human dummy that can have organs removed in the style of the original game. Nothing too grisly, don’t want to scare the kids.

I am organising a cardboard racing game, such as has been done on the Internet recently. Our improvement on it will mainly relate to the track, hopefully adding some jumps and loops. If we build it early though, we could look to add more functionality, but firstly something working would be highly desirable.

Guy and I will present our timetables for finishing these projects by the Hack Evening on the 1st November.


The wiki now supports anonymous edits, protected by a simple maths-based captcha. I will also try to keep an eye on the list of changes to check for malicious damage, but now anybody can edit it without an account!

September meet write-up

Another month, another meet in the Malt Shovel!  We discussed some future events that need some organising. A permanent hackspace was discussed, where everyone was broadly keen on having one, but we don’t currently have the cashflow to consider renting a space yet.  One possibility to raise income  would be to bill the space as usable for telecommuters with appropriately higher tariffs of membership to occasional users.

Milton Keynes Museum

Nicholas visited the Milton Keynes museum and the curator is keen on interactive exhibits.  There’s a number of different types that were raised:

  • A multimedia display triggered by movement or visitor interaction.  It could play audio clips using a microprocessor, or a laptop could be used to show video
  • A server that offers additional information via Bluetooth to visitors
  • A model of some process or historical machine, or technology (e.g. routing comms)
  • An animatronic model using a projector to project a face, and voice clips via a speaker

To see if we could be of service to the museum, a NortHACKton group visit will be organised in early October.

Pinball evening

Adrian has offered to host NortHACKton on an evening in November and demonstrate his collection of pinball machines.  This will be on a day in November, vote here to help choose when. This would probably be a late afternoon meet, followed by a pub trip.

Python hack evening workshop

The next hack evening workshop will be on the 4th October, in the Yeoman of England.  It will be an introduction to the Python programming language by translating concepts from other programming languages. We’ll start at 8pm again with a talk about an Arduino that Nicholas and I have programmed that can communicate with the FluidDB online shareable database.  There will then be a hands-on interactive introduction to the Python language, and then a tutorial, trying to write a small Python program in groups or solo, and then a show and tell of everyone’s work. To learn Python, you’ll need a laptop with Python on it.  It comes as standard on Linux, Windows and Mac users will have to download it.  The Python version should be between 2.5 and 2.7. Everyone’s welcome on the 4th, even if they don’t wish to learn Python and simply use the space to work.  Don’t forget to bring your projects!

London Hackspace visit

Martin and I will visit the LHS in the second week of October hopefully to get some Perspex cut on the laser.  If you want a design cut out (as demonstrated at September’s Hack Evening) then pipe up on the mailing list. There’s a square foot of material (3mm thick, clear blue) for all our designs, so small is beautiful.  It also stops the laser overheating.

Maker Faire

The Maker Faire isn’t getting any further away, and we need to choose what we’re going to try to build by the next pub meet (19th October) to actually have time to build and test it.  Thinking caps on!  In addition to the designs discussed before, Martin also suggested a catapult that fires coins at a set of paper targets or models.  This would also have the advantage of raising money for the group as well!