srimech.com

I’m probably not going to update this site directly much more. I’ve set up srimech.blogspot.com to write new posts on, and I’ll probably change this site to republish comments from there with a bit of perl.

I found this little tracked robot platform at mutr.co.uk. It’s quite difficult to find tracked robot platforms (or even the components) cheaply, but this is very nice for the ~ ten pounds they charge. It contains the tracks, wheels, motors and gearboxes, an aluminium plate for the chassis, fixing screws and some three-way switches and wire. It needs a bit more than just assembly to get it moving - I had to fold and drill the aluminium and glue some of the wheels together, and I found the motor tended to rise out of the gearbox if I didn’t tie it down with some copper wire.

Somewhere I have some infra-red proximity sensors and a camera board I’d like to attach to it to make it into a proper robot. It’ll need a suitable battery and some motor controllers - the Electronize controllers I have at the moment are a bit too big for it.

MUTR sell a lot of useful stuff - I got some Nitinol memory wire at the same time, which is very interesting stuff. Their £5.80 default delivery charge is a bit annoying for small orders, but handily I have some colleagues who also buy from there to share costs with.

I’ve been working on this for quite a while. It’s one of them ‘casemods’ that all the kids are talking about - the mind and display of a Libretto in the body of a ZX Spectrum. More details / more pictures

I’ve not had much to post about recently, due to a rush at work, not being able to get to Newark Kit Car show, and being on holiday. I’m working flat out on a little retro computer project at the moment, which I’ll detail later, but for the moment I’ll just post this picture of a method I’m experimenting with to attach flying leads to flexible circuits.

A few days ago at work we got some new computers in and decided to call one of them ‘Theremin’ since all the others were named after instruments and we were running out of ideas. A quick browse later and I found Art Harrison’s web site on Theremins. This is built from his ‘2006 Minimum Theremin’ instructions and I found it pretty easy to find all the components at Maplin. It’s a simple design, meant more for demonstrations and science fairs than musical use - Art has designs for more sophisticated theremins on his site. I’ve no doubt reduced its musical quality by deviating from his design, but you can still get a tune out of it. I’ve left off the tone control - it’s an preset on the board rather than a proper control - but you can alter the range quite adequately by adjusting the length of the telescopic antenna.

Last weekend my friend Dan invited us all down for a barbeque. A generous offer anyway, but this had the added highlight that Dan had built the barbeque from scratch. It’s a fine piece of engineering - perhaps not quite as stable as a brick barbeque but it served very well and cooked plenty of food for fifteen or so hungry guests over the weekend.

The construction materials are (so far as I remember) 1/2″ steel bar and angle, some thin steel plate, steel mesh and those corner strips plasterers use - the closest thing most DIY stores will have to perforated angle. If anyone else has a go at this, my one piece of advice would be to avoid galvanised metal, as can give off some nasty fumes if heated. Compared to the quantities of ethanol usually drunk at barbeques though, it’s probably a drop the ocean.

Dan also made a giant jenga set by cutting up some planed timber - a very quick and effective party piece. Pictures of that are in the gallery.

EvilMadScientist’s sugar fabber promoted quite a lot of discussion in our office today. Using sugar as a fabrication medium is inspired, but we wondered whether we could use something more accurate than a hot air gun to fuse the sugar. Using a high-power laser would seem ideal, but I think there’s a lot of milage in using a lamp (or lightbulb) and a moving lens or mirror to focus heat on a particular area.

Today’s top tip: Don’t slam your network cable between a door and a door frame. You’ll end up cutting out a section of damaged cable and assembling it as shown. Although, if I do say so myself, the slight over-exposure makes for quite a nice photo.

Last weekend I went on a little exploration of my attic. There are two water tanks up there, quite a lot of wooden beams and lots of rockwool insulation. Not all of the rockwool is in the right place, so I’ve attempted to distribute it properly with a pair of sturdy gloves and a fancy dust mask.

Anthony Axford delivered a batch of quarter-boards of chipboard and some aluminium angle which I’ve used to board up some of my attic. Using the aluminium angle as guide rails I’ve been able to put down boards to create useful storage space while still allowing me to lift the boards up in case I need to do any electrical work in the future. The south side of the attic already contained quite a lot of wiring which I couldn’t cover in case of overheating, but the north side was free of it so I’ve been able to create quite a lot of useful space there.

Happily, a quarter sheet of chipboard is exactly the width of the rafters in my attic. I didn’t know that would be the case when I ordered them - it could be a coincidence but it’s probably something deeply entrenched in ancient building codes that makes things a multiple of one foot sizes.

2GB!! On that tiny thing? Crazy. In the gallery I’ve got pictures of that next to an 8MB Playstation memory cartridge, which is about 100 times the volume. If I could find it, I’d have a picture of my 8″ floppy disc drive next to it. Kids these days. Honestly. Tsk.

I’ve bought this for my new M3 DS Simply cartridge, which promises to allow me to put some homebrew software onto my Nintendo DS. I was introducted to it by a friend at work who has ScummVM working on his DS using the same cartridge, but I’m mainly interested in writing my own software for it. At the moment though, I have no idea what that entails - I’m led to believe the thing has a couple of ARM processors but apart from that I know nothing.