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.

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.

She looks pretty cool, but you got to upload another video of her

… my robots because I'm mostly bedridden, and also because our house has wooden floors, walls and ceilings so is very dark for videos, and we live in the Australian bush so there's not much flat terrain outside to let them loose in. The bathroom is the lightest room and I did take a video of Fluffy in there, but I think the reflective tiled walls were affecting the ultrasonic sensor, as she went crazy and crashed into things … real bull in a china shop. Still, it's good for a laugh if nothing else.

I'll upload it to Youtube and embed it today anyway if I can, but it doesn't give much of an idea of how she normally behaves.

I have never seen a Meccano set in real life, let alone built anything with it, but it looks like a pretty sweet kit. Do you have any video of Fluffy exploring? Looks great. Thanks for sharing.

… around, as it's a very versatile, convenient building system, so long as you don't mind ending up with a heavy robot.

I have one video of Fluffy, but it's not a very good one ( see my answer to Jim the Hermit below).

We have a very dark house due to the dark timber floors and also timber walls and ceiling, and the bathroom was by far the brightest room for filming in … sorry. What with one thing and another (mostly one thing) I've not got anything but very rough preliminary programming uploaded into her Mega 2 brain, but even so, she normally behaves better than this. She doesn't usually crash straight into things, for a start. I think the ultrasonics must be getting confused by multiple reflections off tiled walls or something … I really must get stuck into some programming … it's embarrassing …

She's great! I think the biggest trouble with the ultrasonic sensor in the bathroom is the echo giving it tons more data than it knows what to do with. Many people pair it with an IR sensor to get more reliable obstacle detection. If you ever have time to burn, this is a great site to do it. Glad you found us, and keep 'em coming!

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.

There are a few members here that have made posts about their use of bluetooth. unix-guru seems to be indicating that he will be adding bluetooth programming to his arduino based Penguin bot. mogul has a post or three floating around here about bluetooth. However, bluetooth doesn't have enough bandwidth to really do any kind of streaming video. You would need more of a wifi link for something like that.

Re: Aussies. While searching for the user map I ran across this forum post http://letsmakerobots.com/node/21716 The replies were quite entertaining to me. :) There really used to be a user map. The link for it leads to a blank page at the moment http://letsmakerobots.com/user_map

I guess we will have to wait for our web dev to get better to find out what is up with the user map.

That post about Aussies was hysterical. Rattlesnake serum bejaysus!

They forgot to mention poison jellyfish, centipedes, scorpions and Paul Hogan.