May 18 2010

Buster: A lucky find

Currently got a bunch of things on order, and a nicely full order book. Hurrah.

Yesterday though I spotted something outside a local charity shop. A Fisher Price ride-on electric car.

When I was a child, I used to get a book out from the library over and over again. “Build your own working robot” by David L. Heiserman, published 1976 (ISBN 0-8306-6841-1). The hardback, it was bright orange and missing it’s dust cover. I read and re-read it, fascinated by the diagrams that were inexplicable yet tangibly logical. I must have been 8 at the time.
I wanted my parents to get me a pair of those electric kids cars just so I could make the robot in it; Buster.
At £100 each though, that never happened. And one day some git took the book out and never returned it. I was gutted for a long time.

Last year though, I found a paperback copy on Amazon. And now, for £3 I have the perfect electric car to do it.

After 21 years, I can finally build my own Buster. I have the chance to fulfil a childhood ambition.

I, of course, will blog it. :)

The tech involved is pretty crude by modern standards, being started in the mid 70s. I’m sure it’d be easier to redesign it with modern parts. But I’m going to see how closely I can do it to the original book. Wooden PCB racks, reed-switches and all.

[20/06/2010: Amalgamating old posts from “Dreamwidth Creative Blog” into sci-fi-fox.com to re-purpose DW blog account.]

May 13 2010

Small update

Took a momment out to update the RepRap wiki entry on my printer project.

http://reprap.org/wiki/Bonsai_RepStrap

I think some of the connections I made at the convention at the weekend may be a great deal of help in building them too.

I’m wondering that when the first few machines are working, that I might loan them out to a few artists to see what they can do with them. See what less hardcore engineering purposes they can find for them.

[20/06/2010: Amalgamating old posts from “Dreamwidth Creative Blog” into sci-fi-fox.com to re-purpose DW blog account.]

May 12 2010

Salvage: Adjustable bed and rant

Grabbed the electric adjustable bed from up the road earlier. Could tell it contained at least some angle-iron and a motor, as well as an oversized controller.

It’s about what I’ve come to expect from all commercially available “medical” appliances. Off-the-shelf parts in a design so basic it’s crude. It smacks of zero product development; no refinement beyond the first working demonstration model.

Controls all run on mains voltage so the flex to the massive hand-held controller is about half an inch thick, the controller itself being slightly larger than that used to control industrial gantry cranes. All angle-iron frame, welded, with M6 bolts and nylon washers as hinges. No nylocs, all counter-tightened slim nuts to hold them in place. Even using two bolts as load-bearing end-stops. Considering the bed has two separate “massage” vibration motors, it seems dangerous to use pivot nuts and hold the bed portions raised with a scheme that could easily shake loose over time (and many of the nuts were already loose enough to undo by hand). The internal control box that I expected to contain relays only contained some fuses and a small transformer (probably for the vibration timer in the controller), the rest of the box being 3/4s empty. Another off the shelf project box you could pick up from any electronics hobbiest shop. Connector bundles also held together with a project box. MDF covers for the vibration recesses have been neatly and pointlessly bevelled on all edges, where no-one will see it or or any wire would touch it. The vibration motors themselves have a bolt and washer as a weight drilled into the cooling fans at each end.
Also noticed there’s no packing on the pivot bolts for the actuators so they twist in their mounts when changing direction. This will surely lead to metal fatigue and sudden unexpected failure of the mounts in the actuators cast aluminium housings.

Why is it every single piece of consumer medical equipment is apparently designed as someone’s final GCSE Design & Technology project??

It’s no wonder the devices needed by our most vulnerable are also so expensive when they never refine the designs at all. Even a courteous bit of refinement could drop construction prices by a large amount. Even if they didn’t drop the sale price, the companies would make more money! Where’s the downside? Or is there some bit of safety legislation that demands any “medical” equipment be explicitly built like a 1920s farm tractor?

That said, I now have some short sections of sturdy angle-iron and a pair of mains 250Watt linear actuators rated at 2500N with about 200mm travel.
The reason for it being thrown out? They’d accidentally yanked the mains cable out of the controller box. I plugged the pins back in, changed the fuse, and it worked fine.
Except for a week outside, the foam mattress portion smelled like rancid fish.

Truly, it pays to remember that when something breaks, it generally only means one single part of it has actually broken.
The attitude of the consumer however is far more often that the magic box is dead, so they need a new one. Well, I suppose that is why they’re called consumers.

Wondering if the actuators would be sufficiently powerful to make a small crane. I doubt it actually. Could probably shift a large satellite dish or similar though.

[20/06/2010: Amalgamating old posts from “Dreamwidth Creative Blog” into sci-fi-fox.com to re-purpose DW blog account.]

May 10 2010

Confuzzled 2010: Feedback notes

Notes to send, as I missed the feedback session due to early train:

Furries flock. Having two DJs running dances at the same time in rooms connected by glass doors isn’t fair. One will get an initial group and everyone will follow them, wanting to avoid the “unpopular” dance. Perhaps getting the DJs together to discuss a good order in which to run so the styles flow nicely into each other and everyone gets a fair turn? Or operate one as a chill-out room, so you can sit for a bit but without missing tunes.

While the auction already over-ran by 2 hours, it’s still unfair that only some of pieces in the art-show seem to get picked for it. Apparently at random, and using apparently winning written bids as the start bid. It should be set in stone if a piece will or won’t go to the auction.

The rules for the Dealers Den about no snacks or drinks allowed in to protect dealers works and art-show works alike is a good one. However only if it’s enforced. Likewise the promise that only con attendees would be allowed in, badges on display. It doesn’t give much motivation to follow the rules when I asked if I’d be able to give out complimentary sweets or mints and be told no, then to find people wandering around with pints of beer, wine, drinks, biscuits and other foods. Fortunately the only drinks spilt on my table were my own.

Sharing a hotel with normal folk isn’t a problem. The football fans were a problem for a lot of people though, because they were another large distinct group sharing the same space as the convention. Let’s try and avoid sharing the venue with other large groups if possible.
One way to achieve that of course is to try and fill the entire hotel next time. :)

Den layout was generally pretty good, though from my position I felt there were bottlenecks. I noticed the crowding around Tani and Nightfox Studios, but anyone walking away from them first saw the bare wall and had barely looked around again before they were past my table. There seemed to be a couple of seconds when moving away from the popular tables before people start looking around themselves again. (would be interested to see if it was similar around Jencen and Muzz’s tables, which also seemed to have permanent crowds)
I’d suggest adding another row of tables, so the furthest-back row is facing toward the front of the Den, so there’s a backdrop of interest at the rear of the room. Three rows of faces rather than two, giving the den a fuller appearance. I know this would reduce walking space between rows, but if the rows were turned 90degrees it might work. I would also be easier to work into the (apparently abandoned) idea to have divided IN and OUT lines of the den room, by giving a snaking direction of traffic around the tables. It works in supermarkets, after all.
Additionally, some tables seemed to sit empty for long periods. Perhaps next time dedicating a few tables to an “artists alley”, for those who only want to pop in and do sketchbooks for a while?

Also, I know opening a door is a much simpler solution than getting a fan, but while it may cool the opposite side of the room a bit, it makes the tables by the door really frigging freezing.
While if the only layout change it could have caused a massive corner jam, perhaps Jencen’s laser engraver would have been better suited near the door due to the chance of it putting out odours/smoke?

And additionally, since the conbook’s backdrop would suggest there were accurate dimensioned drawings of the rooms layout, it would have been handy to supply this to the dealers so they could plan from more than the small rendered image on the Dealers page.
Perhaps a large map of the den with who’s where marked and what they’re principally selling too. I know the layout’s in the con-book, but not everyone carries it around with them. Plus it would allow last-minute changes to be made.

Aside from that, can’t think of anything else right now. The registration delays were due to circumstances out of the cons control as far as I understand, as was the behaviour of the few hyper/drunk teenage football fans. Can’t recall if it was mentioned before the con that some of the hotel was slowly being renovated or not. Most rooms seemed perfectly fine (not that I saw many), but some areas were a bit sub-par. Well done on the discount carvery meals though! They were very good value for money I thought. Security also seemed very on top of things as issues arose.

[20/06/2010: Amalgamating old posts from “Dreamwidth Creative Blog” into sci-fi-fox.com to re-purpose DW blog account.]

May 10 2010

Confuzzled 2010: Achievements Unlocked

  • He’s dead jim. – Get con-crud on the first day.
  • Lanyard farmer – Earn enough to order new lanyards.
  • Totally bass-ackwards – Start dancing like you don’t care before having any alcohol.
  • Accountancy 102 – Count in every note and coin, but still have £25 more at the end of the day than you should.

[20/06/2010: Amalgamating old posts from “Dreamwidth Creative Blog” into sci-fi-fox.com to re-purpose DW blog account.]

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