next topic »

[on:]

Hello,

I plan on making a robot that uses 5 - 7 sensors,
there will be one Parallax Ping ultrasonic sensor, 4 sharp
IR rangefinders and probably 2 more infrared sensors
for table edge detection and/or line following.
While I have no doubt that there are enough pins on the Uno
to handle all of these, I'm worried about the memory,

Should i buy a second uno/duemilanove(first one is doing some stuff in garage, don't ask:) or buy a FEZ panda
sadly my budget is only around 30-35$ so I cannot use the Mega  .
I plan on the robot creating a 2D map and navigating according to
that.I plan on using 2DC motrs with pwm speed control, so there's
4 pwm pins gone there and probably 2 more for servos, so since both
have 6 pwm outputs , all 6 will be used.
This is still in the preliminary planning stage and the first
program will probably just implement basic obstacle detection
and from there I plan on expanding it to include mapping capabilities.

Are there any issues with the FEZ panda, I have some coding expereince in c++ and moving to c# will not be too difficult for me,
Even though it runs at 72 Mhz,its also native code,
does this mean its slower than the 16 Mhz arduino in most tasks?,
and what effect does this have on ram??

So, please tell me if this is within the capabilities of an arduino
because if it is, I wont even consider anything else due to the huge
libraries and support community 8-)

So which one FEZ Panda or arduino?

Thanks

[Reply #1 on:]

I plan on making a robot that uses 5 - 7 sensors,
there will be one Parallax Ping ultrasonic sensor, 4 sharp
IR rangefinders and probably 2 more infrared sensors
for table edge detection and/or line following.
While I have no doubt that there are enough pins on the Uno
to handle all of these, I'm worried about the processing power,

I suspect your Uno will have no problem handling these sensors. But of course that is somewhat dependent on your programming skills. Good program structure and algorithm choices usually has a bigger impact on application performance then does the raw processing power, especially in context with micro-controllers. So if the raw pin count covers your I/O needs, you just need to dig in and get started.

Lefty

[Reply #2 on:]

None of the sensors that you listed require much in the way of processing power.

The task of reading the IR sensors is handled entirely in hardware. The actual meaning of the values tends to be irrelevant. It is the relative values that are important, and the raw values present the same relationship.

The range finders and ultrasonic sensors are a matter of timing how long it takes for a pulse to go HIGH. If you need actual distances, some computing is required, but it isn't all that much. Distance is a linear function of time.

Any of the Duemilanove variations would work equally well.

[Reply #3 on:]

Thanks for alleviating some of my fears,
but im not really concerned about the reading the sensors
just the acutal mapping taking place because it will probably be a
2D int array, probably 16X16 or 32X32.

[Reply #4 on:]

If budget is a concern, and it sounds like you are planning on integrating the uC into the platform,
you could look at less expensive clones also, such as the ardweeny or the RBBB, mount them on a wirewrap socket on a piece of perfboard such as velleman ECS 1/2 so you also have a secure place to connect your other circuits also. Will need an FTDI adapter to program them; re-use that to program your 2nd & 3rd robot and later projects also.
2 ardweenys plus FTDB basic is $34 from www.solarbotics.com
ECS1/2 http://www.omnikits.com $3.50 here.
Am sure you could find other alternatives as well.
Strip of wirewrap sockets to plug the ardweeny into:
http://www.marcospecialties.com/product.asp?ic=SIP20L, or ask at gravitech, I purchased strips of 32 socket pins from them, not shown online, you have to ask. Great for prototyping or low qty assembly. I think they have great prices on other arduino stuff as well.  I am integrating a bunch of prominis I bought from them. Couple of female header strips from www.pololu.com, some terminated wires with crimp connector housings, have things going together quickly.

Here's a couple of custom-designed LED assemblies going into Staples stretch pencil boxes with a promini & pololu.com wiring.

[Reply #5 on:]

Thanks everyone for the replies,it really helped
and crossroads, you are right  I plan to leave the
uC permanently or atleast for along time in the robot
so that it can function as a development platform,


Does anyone have the FEZ Panda, what are you experiences, suggestions etc,do you suggest it ???
Does anyone sugest the FEZ panda???