Let's Make Robots!

Fluffy (Meccano robot)

Obstacle avoidance mostly, with light and distance sensing

My initial intention to build robots came out of being a mostly bedridden invalid, as a sort of surrogate set of senses to travel around the house for me, but I got hooked :-). So Fluffy is more of an accident than a robot (or rather, a series of accidents).

She's been knocked together from Meccano so as to be easily modifiable, and carries an Arduino Mega 2 (originally a Uno clone, but it died), a a simple H-bridge motor controller and a decent-sized breadboard for experimenting with sensors etc. She's the first robot I ever built (or rather, started building), and the way things are going she may be the last, as she never seems to be even nearly finished.

She's a test bed rather than an actual robot, though she does charge around the house avoiding obstacles (more or less) and terrorising the dogs if she's let loose. She did detect light, and beeped faster or slower in brighter or dimmer surroundings, but the light sensor has packed up and I've yet to replace it. She also had an LCD mounted on her back with a distance readout but, as it could only be read when she was close up, I decided it was pointless and removed it. I intend to fit another light sensor to have her reverse smartly out of dark (and therefore enclosed) spaces such as under chairs and beds. I also plan on a sound sensor which will enable her to respond to a clap or shout. Beyond that I haven't really any fixed plans for her.

She's been around in one form or another for a year or so now, I think, and I do bits and pieces on her in between building Lego Mindstorms robots, bots with multiple legs, other misbegotten Meccano and Lego creatures and B.E.A.M. bots (though the Lego bots are the only ones ever to get finished).

If I had my time again, I'd build her very differently; for a start, I wouldn't use Meccano. Though undeniably convenient, it's unfortunately very heavy indeed. When Fluffy runs into your shins, you really know you've been in contact with a Meccano robot. She's a walking (well, rolling) history exhibit of some of my robotics phases, so I probably won't dismantle her or make major changes.

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G'day Gairlochan,

Yet another Aussie here (well POM import from a long time ago actually)   Have to agree that the modern Meccano is way worse than the original - whats the idea of triangular axles!.  Brought a few sets when my kids were younger but I seem to be the one who used it the most!  I reckon your robots are great and already more advanced than mine, but then again I split my hobby time between many hobbies.  Listen well to Oddbot he is one of the many Gurus here on LMR.

truly boggle the mind. They make about as much sense as square wheels.

It's good to see another Aussie on LMR! Great job with the mecanno!

I agree with you that mecanno is a great option for robotics. Although I grew up with lego I bought mecanno sets to build my early robots.

Since you can't get around much to take videos why don't you let your robots do it for you? One of my early robots, Pictomatix could be controlled with a TV remote and had a camera for a head. I used him one day to video another robot of mine. If there is a mirror at floor height then the robot can even video itself.

As Mr. Bird mentioned, using bluetooth or WiFi to link your robot to a tablet or laptop could make things easier for you. Admittedly you would need to write an app or something in that case.



I had an idea there was at least one other.

I was already into Meccano when I took up robot making (though I also grew up with Lego in the sixties and seventies), and it just seemed the obvious thing to build one out of, and I can't think why it's not more often used. They have something similar over in Yankee Land, don't they? Erector or something? Maybe it's not a household word as Meccano is in Aus/UK/NZ etc. It's bloody heavy, though! Pity there isn't aluminium Meccano … that would be the perfect robot development platform.

My original reason for getting into robotics was because of limited mobility, and I still have vague intentions in the direction of a mobile pair of eyes, using my old iPhone 3GS as the eye (I have some software that transmits what it sees onto a browser page on my Mac, I can't recall just how at the moment). Maybe when Fluffy's actually properly programmed I'll get around to it. I'd just done very basic preliminary programming on her when the USB chip on her Arduino Uno died, and I never got around to programming her properly.

But my intentions to build a mobile eye got hijacked by more interesting things to make (to me, anyway) once I started learning about robots. I can get around the house some days, as long as I'm careful and don't stay up too long, but my illness is much more complicated than just a mobility issue. It's autoimmune and neurological and I get really easily stressed out and overloaded and just crash and end up really ill for weeks if I try making anything ambitious, so I keep it simple and containable.

My original training was as a TV repair technician back in the early eighties (I play electric guitar and wanted to learn to repair and modify guitar amps rather than actually repairing TVs), and I still much prefer analogue electronics, including tinkering with valves. So I do find the whole digital electronics explosion hard to get my head around. Still, programming robots is fun, up to a point 

Glad to see you here! The robots are really cool. When I was young my older brothers and I had "Machleen" (sp?) Like Meccano, just a German version I guess. I wish I still had them. Gears, wheels and pulleys all nice metal. And of course Lego also, I cannot see a kid growing up without, my son has crates full of them he is saving for his own kids.

You have stoked my interest in Meccano for making a robot... 

So cool to have another "Jill of all trades"!

Marklin, perhaps?

Yes, it's strange for me seeing another woman, especially one close to my own age. I'm used to being the only woman on this kind of forum, certainly the only middle-aged one.

Lego Technic/Mindstorms is good too, and cheaper than Meccano.

Actually there are quite a few Aussies on LMR but we are only a small percent of LMR.

Probably the two things that stop mecanno being more popular is the price and as you mentioned, the weight. A heavy robot needs more power to accelerate, decelerate and move in general.

If analog electronics is your thing then look into "beam" robotics. This sort of robot is not programmed and uses a lot of op-amps and simple analog circuits for the brains.

Chips like the 555 timer can be used to generate the pulses needed to drive servos. You can also use a comparitor to generate a variable duty cycle from a triangular waveform and an analog input.

I think you could probably have a lot of fun with a large breadboard and a handful of analog IC's.

… Meccano motors and gearing but, partly due to her weight and partly due to the fact that modern Meccano motors are gutless in the extreme, when I first fired her up she wouldn't budge. I picked up some 6V gearmotors from Robot Gear Australia and she whizzes around now, though at 2Kg she's no lightweight.

Modern Meccano isn't really very expensive, but it isn't really very good either, so you get what you pay for. Most of my Meccano is vintage stuff, lots of lovely brass gearing and other similarly elegant bits which would look seriously weird on an otherwise modern robot.

I do like BEAM robotics, but there are complicated reasons why I've never got very far with it. I love those little minimalist bots, though, photovores and the like. So analogue and unpredictable. I've built a circuit or two, just discrete transistors, solar cell and motor, just haven't got it together to build the whole bot … yet.

Have you ever considered adding something like bluetooth and "listening" via a tablet or laptop?

Also, you realize ultrasonics generate a bulbous cone of sound rather than a laser beam like sound wave? I believe there are Maxbotics models that have a more confined cone, but, they give up range for a more confined cone of sound.

… anything with a sensible purpose. Getting into bluetooth and similar is way more complicated than I would want things to get. I get easily overloaded and stressed by complexity, because of the chronic neurological condition I have.

No, I didn't know that about ultrasonics. I suppose that's why Fluffy went crazy in the bathroom. While never entirely predictable, she is much better behaved in the rest of the house, though with hardwood floors and lots of glass, I guess there's always going to be that tendency.

It's been suggested that I add an IR sensor to help control this, and I might look into that option, as I have a few lying around somewhere.