lightget-misc — Miscellaneous questions and ideas

[Lightget-misc] Development ideas

[Risto S V. <rva...@cc...>]

I think modularity in hardware (power supply, main unit, LED
arrays) was a really good idea.  You can verify each module
separately as you build them, and when you experiment with some
new module, you don't have to rebuild the others. It also gives
you flexibility as you can change LED colours etc. easily.

As for future directions...

Maybe we could specify some hardware interfaces, like a dumb
parallel port interface and a more advanced serial
port interface for using programmable lightget units. 

Another option would be to specify the interface for device
drivers. The hardware units could be very different, but each
would have a dedicated device driver with a standardized
interface. That way each driver would have a uniform interface
available for other software to use. 

I think the latter option is worth considering. For me, software
looks like a very good tool for abstraction and hiding nitty
gritty details. Implementing drivers for all the operating systems
and hardware we want to use is a bit of work, but then again, we
have a good bunch of people who volunteered as system programming
engineers! =)

One option for hardware would be to get some kind of a
microprocessor and just run NetBSD (or another suitable OS) on it. 
In addition to being an interesting idea in itself, it would let
us get rid of the PC part...  I was told we could take a look at
so called "suite chips", which are available as MIPS, ARM,
PowerPC, SH3/4 and Xscale architectures, for example, and could be
used for running NetBSD. 

The catch is...  how hard is it to build your own computer? =)
Probably we'll have to document at least a basic lightget design
(no programmable hardware) and an advanced lightget design
(interrupt controller, cpu or some other programmable hardware),
because the skill level in electronics each of us has is quite
variable. 

We could also consider some stuff like that sold at
www.coolkits.nl - for example the I10 - 16E would allow us to
control quite a bit of stuff over ethernet, only thing is it's a
bit expensive ($200) =)

Btw. Should we adopt some kind of a real-time communication method
for meetings, IRC for example?

Varis

[Lightget-misc] Next steps in Lightget

[Risto S V. <rva...@cc...>]

I made a release of some preliminary junk files under the Files
section at our SF page,
https://sourceforge.net/project/showfiles.php?group_id=43535 . It
contains some very sketchy files: a circuit diagram of sorts, a
parts list and some source code snippets. I created a .zip archive
in addition to the usual .tgz, because some of you seem to make
use of Windows.

Perhaps we need a bit of project management at this point, as the
number of people has grown a bit... Maybe we should discuss what
kind of hardware we want to develop (for), so we have at least
some shared goals or interfaces?  

Does anybody have project management experience on hardware or
electronics projects? My primary knowledge comes from unix/network
programming, which I do for living, electronics is only a hobby
for me. We've been using SourceForge in the Geome project for last
2 years, so I somewhat know the project management features here. 

Varis

Re: [Lightget-misc] Working on ideas

[jhay s. <jha...@ya...>]

Hi guys,
Interesting discussion you have... 
I guess an idea of having a separate device. We can
use this 8 data pins and with a single microprocessor
we can have as many output as we want...

Just a reminder we must use an isolator let's say an
opto-isolator to isolate your device and protect your
pc from electrical charges....

If you are getting an input be sure to use a voltage
regulator to have an approximate 5V.

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Re: [Lightget-misc] Working on ideas

[Tb. M. M. <ma...@ya...>]

hi, all .
I guess the led can be made in matrix, where for 8 pins (data) if we divide
by two we would have 4 rows and 4 cols, so we can have for about 16 led that
can be controlled, off course the circuit would need a little addtion
/changes.

And for the main unit, i guess we can make an API that can be ported to any
platform. And the communication that understood by the MikroProc will be the
same for any OS version.

Thanks
Mahfudi


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[Lightget-misc] Working on ideas

[Risto S V. <rva...@cc...>]

Ok, I added everybody to this new nice mailing list for better
communication. I also added smiley95 and alteest to project
members at SF. Here we go... 

>----- Forwarded message from Bruno van Dooren -----
>Hi,
>thanks for your message.
>so if i understand correctly you toggle lines of the printer port low and 
>high to create patterns?
>so that means that you can only address n leds where n is the number of 
>writable io pins?

Yup, 8 arrays of leds for 8 data pins in the parport. With my 12V
power, I can put 3 to 5 leds in one array, but they of course
blink at the same time. Think there would be other pins that can
be written to, but data pins were easy to use, and my power source
can't handle much more than 8 arrays...

>how do you feel about the following idea: at this moment i am programming on 
>embedded microprocessors. lets say that i can find a cheap microprocessor 
>with a free compiler. wouldn't it be more powerful to create a printed 
>circuit board (i do that too) with a microprocessor that is able to 
>communicate with the serial port of a pc. then the uP could control as much 
>logic as you can wire to it. you would then be able to issue series of 
>commands that are not limited by the port interface.

Hmm.. yup, why not... if you are up to it :) I was personally
thinking of just a programmable interrupt controller, as printed
circuit boards probably are beyond my electronics skill level...
Even for PIC I would need to buy/build a programmer first, it's
not something I could not do, but probably it's not going to
happen anytime soon. 

One advantage with programmable hardware is that you don't need
the PC to control your lights any more ;) Think about a scenario
where you run lightget out of a battery at your cabin - 3W power
for lightget and 80W power for the PC sounds kinda silly. Of
course you could use a laptop or a non-programmable controller
device with parport.

>btw
>-i assume that there is no time pressure on this project? for my job i do 
>projects with sometimes very heavy deadlines, i don't want to have deadlines 
>in my spare time.

Yes, I was thinking to have little pressure on this project. Open
source in general goes easy on deadlines...

PS. I think I could put up some sketchy circuit diagrams and
building notes, so everybody gets a better view at what the
hardware could be like... maybe over next weekend... I'm having a
flu at the moment, too :(

Varis

>-i am not a linux-unix guy. i work on NT/2K. i could make drivers for those 
>OS's though, and i could write software for the uP, and create the print 
>design
>
>regard,
>   Bruno.
>
>
>----- End of forwarded message from Bruno van Dooren -----