[dba-Tech] OT: Is anyone into controllers?

>What do you use for simulation?

Of the circuit?  I haven't gotten there yet.  I downloaded the EagleCad free
package but haven't even created a schematic yet.  I really just decided to
get into this stuff last Friday.

Of the Software?  The Atmel stuff has an emulator built into the IDE so you
can run your software and actually watch the registers, memory etc.  I doubt
that it will return real-time graphs though.

Part of the problem here is that with controllers the physical circuits are
generally pretty simple, and the timing generally isn't critical.  The
software does all of the work.  Yea, if you get into things like A-D and D-A
then there is the physical response of the analog part as the components
change but with much of what a controller will do, the physical circuit
timing simply doesn't matter.  What difference does it make if a response to
a window opening in an alarm system is off my a few microseconds?  

I am building a little system to turn on/off the (added on) lights on my
son's Ride-On Gator toy.  It needs to sense power applied to the wheels,
then turn on the headlights.  When power is removed from the wheels, it
delays shutting off the lights for 30 seconds.  Hardware simulation pretty
much not required.

I will be building a motor controller for the wheels.  One problem with
these Ride-On toys is that 12V is applied all at once to the wheels, and
with the sudden start (high torque), after awhile the gears strip inside the
gearboxes.  This will be a simple controller, which watches the accelerator
pedal (currently a simple on/off switch).  When turned on, it will use PWM
to ramp up the power applied to the motor so that torque is applied over a
second or two rather than instantly.  Again, is simulation required?  Well,
in this case I need to be able to watch the software execute.  The hardware
will be an H-Bridge Mosfet circuit applying power to the wheels.  I suppose
simulation would be nice there so I could see what happens with component
changes - do the mosfets spend much time in the linear region, and if so how
do I modify the circuit to turn on the transistors harder (quicker).  

In the end though, I am a hobbyist, not even an EE so my understanding of
that stuff and even how to create and run simulations is rather weak to say
the least.  Are they available with the EagleCad?  I don't know.  Googling
on EagleCad and Spice returns hits that indicate it might be.  Given my
budget, even if it doesn't it probably doesn't matter since I probably
couldn't afford anything that would have that stuff.

John W. Colby
Colby Consulting
www.ColbyConsulting.com

-----Original Message-----
From: dba-tech-bounces at databaseadvisors.com
[mailto:dba-tech-bounces at databaseadvisors.com] On Behalf Of Lembit Soobik
Sent: Tuesday, September 26, 2006 9:59 AM
To: Discussion of Hardware and Software issues
Subject: Re: [dba-Tech] OT: Is anyone into controllers?

you may want to check the Olimex site. They have quite a few free CAD
packages listed.

What do you use for simulation?
I have got TINA, which let me do quite a bit, but I have not got all the
spice models yet.
TINA includes also a PCB package.

Lembit

----- Original Message -----
From: "JWColby" <jwcolby at colbyconsulting.com>
To: "'Discussion of Hardware and Software issues'" 
<dba-tech at databaseadvisors.com>
Sent: Tuesday, September 26, 2006 2:35 PM
Subject: Re: [dba-Tech] OT: Is anyone into controllers?


> Lembit,
>
>>and then the PC board needs to be designed. have to find out which SW to
> use.
>
> A few cad packages discussed briefly
> http://www.ladyada.net/resources/pcbdesign.html
>
> I am looking at EagleCad since it seems to be widely used and lots of 
> people
> know about it.
>
> http://www.cadsoft.de/
>
> They have a FREE package that is fully functional but will only allow two
> trace layers and a smallish PCB size, still plenty big for small 
> projects -
> 100x80 mm.  And if you decide to pay, the next step up is fairly 
> reasonable
> though a bit steep at $600 for the entire schematic / router.  And... 
> There
> is a "non-profit" license (fits you I think) for $125 which upgrades the
> free to the standard version (4 signal layers and 160x100mm size).  I 
> think
> I am going to do that if I like the free version.
>
> And to top it all off, they do everything in English and GERMAN!  What 
> more
> can you ask?  ;-)
>
> As for the upload/download via USB, I think the Atmel stuff has cheap 
> boards
> already designed (for sale) and software in place to allow this, another
> reason to do the next version with those processors.
>
> John W. Colby
> Colby Consulting
> www.ColbyConsulting.com