Older blog entries for slap.fish (starting at number 3)

not much progress on 48k for awhile - I'm in the midst of major house renovation/extensions, which, amongst other things, means that every scrap of storage space is packed full of boxes - including the spare rooms.. one of which will become the new workroom, and doubtless will be the last I'm allowed to finish and get my bench and equipment set back up again.. woe..

still.. despite all the moving around, 48k has stayed on it's stand in the garage like the very heavy, very complicated looking, shiny, and extremely dangerous if fallen on by thing that it is.. like it's somehow immune to the chaos going on around - which seems somehow gratifying.

During the course of the work on the house - every single builder, carpenter, bricklayer, plumber, electrician, apprentice thereof and general gawker has asked the same questions, in the same order - without fail.

What is it ? What does it do ?

Despite giving quite a few different variations on the same general theme(s) that qualify for answers (remote control robot, robot for retrieving small objects, robot for roving around autonomously, robot for throttling neighbourhood cats that dare to defocate under the rhododendrons, robot for world domination as long as there are no steps etc.) - I know they all think I'm not quite all there.. in the nicest possible sense of course - though I've noticed they do scrutinise free cups of tea just a little more closely afterwards.. hmmm. There is often a third question (perhaps optional ?) - which is 'So what do *you* do ?' - I'm not quite sure I ought to wonder too hard on why they ask that one.

anyway.. in another month or so I may be able (allowed?) to get back to it - does anyone know the typical ultrasound signature of the average un-house-trained cat ?

1 Mar 2006 (updated 1 Mar 2006 at 11:09 UTC) »

I promised a more up to date picture of 48k - so:

latest pic

It's in a somewhat 'stripped' state at the moment - the arm base joint, batteries, and electronics housings are missing - but it shows the mechanical layout clearer.

There is very little in the way of actual control elements in place yet - but I thought people might appreciate seeing a bit more of what's involved in the actual mechanics, as this is an area often overlooked. I for one like to see how something works under the skin.. a robots 'bones' if you like - the hardware solution is just as interesting to me as the software.

a couple more, showing some details:

drivetrain suspension


I will be remounting the arm base joint and batteries soon - and then onto connecting up the pneumatics.. then it'll be on it's wheels and under power for the first time sometime soon [rubs hands and laughs like Vincent Price].

Some background on 48k - here are a few pics showing a somewhat disjointed progression of the build:

http://homepage.ntlworld.com/retro.spect1/robot.JPG http://homepage.ntlworld.com/retro.spect1/rob1.jpg http://homepage.ntlworld.com/retro.spect1/rob2.jpg http://homepage.ntlworld.com/retro.spect1/rob6.jpg http://homepage.ntlworld.com/retro.spect1/rob7.jpg http://homepage.ntlworld.com/retro.spect1/rob8.jpg http://homepage.ntlworld.com/retro.spect1/rob9.JPG

You can see that early on, I'd planned on driving the wheels via differentials and a single motor - that was changed in favour of a gearhead motor per wheel, arranged to drive the wheels directly (via couplings). Most recently, I have altered the drive arrangements again to a belt system, which means the drive train now has some allowance for slip built it, and any shock torques are unlikely to damage the gearheads - an extra 2:1 was used as it was looking increasingly likely that climbing a 15 degree incline was going to be close to exceeding the motors capabilities.

Last night I had the first wheel under power, using the new layout, and it works great - another added benefit of belt drive is I can quickly disengage the tensioner, effectively disconnecting drive, and allowing a freewheel mode - which I'm sure will come in useful when it's finally out and about, and I need to tow it home on a rope - picking it up will not be an option!

Well, 'Hello World'... I've been regularly checking up on Robots net for a couple of years now - but have finally motivated myself into joining.

I am currently working on this:


This picture is a little old now, and I will endevour to get something more up to date on my site soon.

It is (will be) an autonomous Rover - as you can see it is no small undertaking, and the project is in it's 3rd year, I will add it to the list of robots when I feel it qualifies - for now, I am still tinkering with the mechanics, and getting them just right, before I set it down and get out the way (it will be in excess of 100kgs when fully built).. a Rover shaped hole in the wall is a distinct possibility in the future - not to mention me running down the road frantically warning people out the way.

Excuse my irreverence.. it IS a serious project - I, however, am constrained otherwise as, being only a hobby - it is the only way to remain sane. How else does one keep smiling, night after night in the shed - setting titanium turnings alight and picking aluminium swarf from surprising places ?

By the way - the large assembly torward the front is the base joint for a substantial arm, which I have provisionally pegged at a 5kg payload, fully extended (approx 1 meter)

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