The summer feels over, but despite some shock showers on Monday the space was open. Adrian took the clock we were given by Nottinghack (couriered by Martin) and with Mat started writing up what they found inside. A number of repairs were performed by a few different people, fixing a bicycle inner tube, a DVM, and the identification of a car part for order.
We also discussed what events we could run at meetings. Some suggestions:
- Nanode workshop
- Photography (light painting)
- Kinect hacking
- Revisiting OpenCV hacking
The idea is for very limited scope projects that allow a sense of accomplishment within a few hours. Suggestions are welcome on the mailing list.
Date of next meeting: 19th September from 7pm
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.
The next meeting is on the 27th June.
Our next evening talk, Monday May 16th, will be about 3D printing, the different types available in both professional and DIY versions. We will cover everything from the ground up so the talk shall be suitable for people with no prior knowledge on the subject. New people are always welcome along and all our talk evenings are free. We shall be at NSME from 7pm onwards with the talk starting at 8pm. It is generally informal in its style so if you have any questions during the talk please feel free to ask them. Talks aim to be about 30 minutes but interesting ones tend to ramble to about an hour. The clubhouse will be open afterwards for more specific questions or general project work.
(The Makerbot, just one type of DIY 3D printing)
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.
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 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!