First Robot From Bits Around The House

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I ordered the EZ kit as a project to do with my 6 year old son. We watched the EZ-box video and intended to build that with him first up, however was given detailed instructions that "real robots had to be at least 4 feet tall!". With that design brief combined with a self imposed restriction to only use materials I could find around the house WE built the following. Its not C-3PO' or even half finished yet -but my son, James, has had some fun playing with it (hopefully learning something along the way).

Here's some videos of early testing:

One arming working only and some basic voice activated head movements

Move around based on wii control

Future additions include ir & Ultrasonic Distance Sensors for autonomous movement.
A better arm with the other working
H-bridge and more powerful motors (as the servo motors struggle under the weight of the beast!) + new wheels (my improvised CDs wheels don't work very well)

Will post future updates as we progress
2nd Prototype
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1st Prototype
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August 10 2013
that is so neat for your kids...

November 2 2013
Finally got the h-bridges wired up!
Here's the test video - as you can see there are still a few bugs to work out :-)
November 2 2013
Here was my first attempt using a 4 channel Dagu controller - unfortunately i didn't count on the motors i was using drawing more than 4amps per channel (so eventually smoked it :-) ). It worked well for a while and gave me enough time to find out a single 7.2V 6800mAh battery was not sufficient to run the 4 motors (i think the current draw was too much).
The 6v 300rm geared motors were rated at 2amp so i thought the Dagu was worth a try as it is cheap and all on a single board.
I clearly went over the top using 300rm motors with 15cm wheels - even running this a 50% - the robot moves very fast! too fast.

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Here's the switch setup - one for an on/off and the other push button to disconnect the h-bridges / motors. with 300rpm motors at full speed - you need this as the robot is very fast!

My son - labelled the robot :-)

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one burnt out controller - too much current :-)

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The new 60A Dual Motor H-Bridge Drivers wired up. These are e-bay cheapies - so i doubt they would handle 60A for very long.. but fine for 2-6a that i am working with.

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To run the 4 300rpm 6v 2a motors i added 4x 7.2v 6800mAh nimh batteries (connected in parallel). To be safe i charge each individually...

Here's the batteries...

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Will upload some more videos after i sort out the motor control - given the speed to the motors, i need to write some code that accelerates and deaccelerate the robot so it does not tip over when stopping or starting... also need to figure out how to control the custom movement panel speed control - i can set the speed via the script but it doesn't change the panel itself - any thoughts appreciated?

When stopping from speed it can faceplant as the controller breaks the motors (it you watch the video posted above you will see it is a little top heavy!). Poor old head is now a little wobbly as it has face-planted one too many times :-)
November 2 2013
Cute. I see you have been bitten by the Bug. It is a passion for me. Sorry the wife does not support your efforts. It can be a truely marvelous experience.

Good Luck on future builds.

November 3 2013
Agree - it is fun. The intention was to try and pull together something fast on the hardware side so I could concentrate on developing some interesting software for the bot. Being driven by a 6yr olds demands has meant the bot was bigger and heavier than originally envisaged! Those tiny wheels supplied in the kit did not cut it for the grand imagination at play.
But it has taken a lot longer than anticipated! I failed to realise the amount of tinkering / experimentation required just to get the bot to do the basics. As you can see - constructing things is not my day job - but have had some fun.
It's interesting - if the new ez-robots had been available when I purchased, I would have probably just bought one of the full kits. Probably still will - But I'm not sure that I or my son would have learnt as much in the process. Certainly glad I took the creative approach first. There is something to be said for working creatively with the tools / materials available to come up with a unique bot!

at some point I will have to splash out and get the new kits as having a 4ft plus bot fling around the living room at high speeds is not ideal!
Will continue to play around and see if I can refine this bot a little further.

Oh yes, and the wife is slowly warming to it :-)
Published on Saturday, May 25, 2013