Posts tagged: scavenging

Jun 06 2010

Up the road from my house, the same place where I got the mechanical bed, is a pile of debris taller than I am. It appeared today while I was in the city. It seems to contain a lot of household items, bits of furniture, appliances and lots of wood and metal.

It’s raining outside. I’ve just taken a leisurely walk in it. It makes everything calm.

The chip and ply in that pile probably won’t make it through the night, and the proper wood will not likely fair well in the high humidity and warm atmosphere. On a colder night it would absorb less.
I already have the OK to take things from the pile, but at gone midnight it’s not the best of times. Still, there should be something worth salvaging tomorrow.

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

May 27 2010

Scavengers amazement

I just want to say, I’m always amazed by the things people throw away these days.
If the adjustable bed I found a few weeks back that’d only had the cable pulled out (contained some ok motors, a lot of angle iron, two 250Watt linear actuators and proof of my disgust of commercial medical equipment design), today I found a 19″ TFT monitor, a proper powered photo-scanner and a PC base unit with a dual-CPU mainboard (admittedly full of twigs, but it’s been dry recently and it was under a tree).

I asked the householder first, and they said the monitor still worked when it went out. After a day of safety drying time and checking inside the housing for debris, I’ll give it a go.

How old will I be when someone just chucks out their old household Replicator or robot servant because they can’t be bothered to feed it into the recycler?

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

Apr 22 2010

Get angry and build robots. Part 2.

More tinkering today.

Pulled the frame apart and flipped it over to give the motors more ground clearance and enough space for a trailing castor.
Rather than cut up the push-scooter bearing tubes, I made a new longer one from a piece of old vacuum cleaner nossle and bolted it into the clamp from an old satellite dish mount. That gave me some bolt holes and nice steel plate to attach some more scrap 1″ box section to as an angle-block. Another couple of bits of smaller box-section went on top again to provide rigidity.

I’ve run out of M6 bolts now though, so will have to get some. Studding would probably be better though.
The motor assemblies were already made up, so it’s really only the frame that’s the product of the last couple of days.

The motors look a little wonky because they’re not bolted down properly. Neither are the bearing-blocks, which’ll need three more M10 carriage bolts. Probably want to put some fibre washers between the motor mounts and frame to help prevent damage to the aluminium gearbox housings.

Here it is with the existing battery box roughly in place.

It’s a large box because it contains a commercial van battery (12v, Lead-acid), as well as positive and negative bus-bars, keyswitch, automotive fuse panel and emergency-stop button on the rear hatch.
May had a high-current plug to it too to allow it to provide jump-starts. If I find one of them laying about anyway.

No motor controllers as yet. I still need to test the stall current of the motors (12v, 180Watt, ~220rpm geared).
Wheels are ten-inch pneumatic sack-barrow wheels. Freewheeling hubs were previously ground off and fixed hubs with a coupler-dog brazed up and bolted on.

Got some aluminium car-phone enclosures with surface-mounting holes that should take a controller each quite nicely.

Whatever this ends up being, it’ll be pretty powerful and be able to go a long way.

Need to make mounts to secure battery box and fork-extensions to turn the current front wheel into a castor. Wanted a pneumatic castor, but there’s not enough space under the frame currently. Maybe later.

Will keep my eyes on the river; see if a shopping trolley turns up. A trolley basket could be a good addition to it for the moment.

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

Apr 19 2010

Tinker tinker..

I wonder why no one makes a toaster with a light sensor so it toasts based on how dark the bread gets.

Found another electric golf caddy today. Lightweight, good frame. Wheels from the larger robot project may fit it. Think I may be able to modify it to carry the UKFur shop, which’ll be handy for getting to Confuzzled.

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

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