CNC Quickstart

This guide will get you running with the CNC for manual machining operations.

Turn it on!

There are three powered units:

1. computer & monitor

2. the electronics and stepper motors (powered by a computer power supply)

3. The CNC cutter, after turning it on at the wall, you also need to set the direction of the cutter, and turn the speed up. It will not turn the cutter until the speed is set to zero and then increased (so it doesn’t start spinning by accident)

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Robotics: Adaptive Control and Vision

Our robot arm is learning to control itself from optical feedback alone! We connected the Lagadic’s visual servoing platform (ViSP), OpenCVs robust homography estimator and University of Edinburgh’s Locally Weighted Projection Regression (LWPR) adaptive control to create a software stack for a cheap USB robot arm toy and a webcam. The hardware cost about ¬£48, and it took us 6 weekends to connect up cutting edge open source research software. Yes! All this software is free! It’s been paid for already. I hope this article will guide people towards making use of these valuable public domain resources. We used an adaptive control scheme so at no point was robotic geometry measured, and instead the software *learnt* how to move the robot from experience alone.

Motivation

To recap (here and here), our goal is to build high precision robot systems using cheap components, and now we have actually tried a control installation. The existing approach to precision machinery is to spend lots of money on precision steel components and more or less control the machine open loop (without feedback). CNCs are a good example of this where the lead screws are *really* expensive. This approach made sense when we did not have cheap methods of precision feedback, but now we have cheap cameras and cheap computation (thanks smart phones), an alternative method for obtaining precision could be to just to use dodgy mechanics and closed loop control (feedback). Visual feedback is particularly attractive because: its easy to install; it is contactless (so does not affect the motion of the thing you want to control) and it doesn’t wear. With vision you can just slap markers on a mechanical part and off you go (with the appropriate software).

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Mark I Mug Plotter

Someone at work broke my favourite mug. Well, the freebie mug I was using. Clearly I needed a new one, and the only logical solution was to build a machine to draw the image of my choice onto a blank mug.

Evil Mad Scientist sell an egg bot kit – it draws a design onto an egg (or other broadly spherical object) using a couple of stepper motors, controlled through an Inkscape plugin. The control board is available separately (the whole project is open source), and is a fairly neat 2-stepper and single-servo controller, connecting to the host PC as a serial port over a USB cable. Hence most of the electronics and software were already taken care of, and I could concentrate on the hardware.

A collection of laser-cut bits of wood screwed together with some wire hanging off.

The partially assembled machine

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Laser-cut PC case

There are a range of mini-ITX form-factor motherboards these days, usually supplied with a low-power CPU as well as the normal on-board options such as LAN and audio; just add memory, PSU and some form of storage to get a complete, very small PC. Oh, and a case, which is usually where the fun begins.[…]

Laser Cutter

Edinburgh Hacklab is pleased to announce the arrival of a rather special bit of equipment, a laser cutter. So what does one do with a laser cutter? It enables high resolution (0.0254mm/1000dpi)¬†engraving and/or cutting of a wide range of materials including Acrylic, Crystal, Bamboo, Cloth, Fabric/Denim, Fiberglass, Glass, Laminated Plastic, Leather, Marble, Plastic, Paper, Rubber,[…]