I've been reading the datasheet for the LM7805 -

http://www.fairchildsemi.com/ds/LM/LM7805.pdf

Looks to me like a problem would be the dropout voltage of 2V.  I read this to mean the 7805 will stop outputting when the input voltage dips below 7 volts.  That discharging RC battery wouldn't last long like that, would it?

Would 7.2V really be a heat issue at that low of a power draw?

Is the project book copyrighted?  Is there a pdf available to download?

It may not be wrong.  Mouser often has cheaper prices than anywhere else for Arduinos.  Arduino Mega2560 for ~39.00 USD: http://www.mouser.com/ProductDetail/Arduino/A000067/?qs=sGAEpiMZZMt0re6d%252b2Rx9v%252bc%252bQEIaOW9

Well, for 39.99 I couldn't resist.  Just put one on order - site is showing them on backorder.  Hopefully it won't be too long.  Thanks for the info guys.

Arduino Due now available for order at Mouser (A000062)!  Small quantity on the way with a large order coming in November.

-Tim

Just went to your link - I'm assuming the 36.99 price I saw was wrong.

Thanks for the suggestions.  I have decided to name this bot Box-E

Too many sensors?  Didn't know that was possible!  $3 on ebay, so why not?  Even with 4 ultrasonics, I'm still at less than half the cost of one PING sensor.

The top box is a Stellaris Launchpad box, the bottom box is an MSP430 Launchpad box.  The shame is that there isn't a single TI part in the robot, at least as of now.  The microcontroller is ATMEL and the motor driver is Toshiba.  Sorry TI 

The box is not a great look, but I find it to be a great platform while I figure out what I want to do.  Kinda like breadboarding the chassis.  It's my second bot, so I'm still learning what design consideration to keep in mind.

What should I call this robot?  Right now it is running a Nano, but it may end up with a Mega, or possibly a Nano and an MSP430 - so the name needs to be microcontroller and brand agnostic. 

Have you considered buying an HC-SR04 ultrasonic sensor on eBay?  They are about $3.

I've found Texas Instruments to be very generous and fast with their samples.  I don't try and order once a week or anything though.

What's the matter?  You can't find people willing to work for $5/day in your neck of the woods?

Fantastic job on the clock.  You had to do quite a bit of engineering on the display and the interface.  Your sister had to be stunned by this clock.  I really like the IDE cable!

Which IC?

A lot of those small motors are 3vdc.  The motor still spins freely or is it seized up?  Without specs on the motor there's no telling.  Pictures?  Interesting that the motor driver chip got red hot without failing.

I was pretty excited too.  Awesome to be able to buy those boards and chips for so cheap vs. Arduino.

You should be proud of your project - very impressive work!  You ought to make an instructable for it at instructables.com.  What is your source for the LCD screen and how much did it cost?

Any video of it in action?  I would like to see your code - I just wrote code for a digital clock using LED's.  Looks like a pretty slick project so far - very clean.