Friday, 20 April 2012

Building Mmmm Bot

Me and John both had a bit of spare time on the same day, so we decided it was time to make some headway with the actual robot part of the robot. I've never attempted to drill aluminium before, so John did the bulk of the building work while I bolted a few bits together and did a bit of marking and measuring. Here's John with a drill:

John doing metal work
Apparently my old hand-me-down Black And Decker drill verges on prehistoric, but it did the job any way. I now know the key with drilling metal is to work up through the drill bits, gradually wearing away the metal, being careful not to let the drill bit catch and fling the metal away.

Anyhoo, after a bit of work, here's the first fruits of our labour:

Our first motor with it's main hole drilled in the aluminium frame

The motors output a lot of torque, so we couldn't just mount them on the balsa wood that makes up the bulk of the Mm Bot's chassis. These guys needed mounting on solid Aluminium, which is bolted (along with the motors) to the inside of the robot. Annoyingly I'm still suffering from bolt shortages. There's so many different crazy sizes, in both empirical and metric, with different heads and lengths and names. Then as the cherry on top, everything needs a different one, and nothing tells you what it needs. Grrrr.

Motors and wheels attached to chassis

Despite the lack of certain supplies, we eventually got the motors bolted on and the wheels kind of attached with the wrong sized bolts sticking out by a centimeter, as you can see above.

Next up it was time to start layering components in the robot to see if everything fits. Here's step one with the Arduino and the Sabre Tooth motor controller that finally arrived in the post.

Mmmm Bot chassis with motors, wheels, Arduino and Sabre Tooth motor controller

You might have spotted that the Arduino isn't the same one I've been using up until now. This is the Arduino Uno's bigger brother - the Arduino Mega! With lots of extra pins and multiple hardware serial ports it'll support more sensors and be able to communicate faster.

Next up, I add the circuitry layer, which still has the Arduino Uno attached:

2nd layer of Mmmm Bot, with prototyping board that sits above motors and Arduino

This massive prototyping board allows me to fiddle with the circuitry to my hearts delight, which is exactly what we need to develop our first robot.

Finally, just to get an idea of what version 1 will look like, I plonk my prototype sensor platform on the top:

Mm Bot 'fully assembled' on the floor

Mm Bot making eye contact (kind of)

You can already see the cuteness from these 2 photos. I especially like the second one with the angled sensors. Eye contact ftw - that'll be the first thing to go in once face recognition works. For now they're just ultrasound, but I have a couple of cameras to hook up soon when we build the newer cuter sensor platform :)

That's all for now. Hopefully by the end of the weekend Mm Bot will be wondering around, remotely controlled by the PC and doing simple tasks like not quite bumping into walls.


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