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We started a new ambitious project. And this time, we are not certain that we
will succeed. So, any help is welcome.
http://www.convict.lu/Jeunes/RoboticsIntro.htm
http://www.convict.lu/Jeunes/RCXCam/RCXCam_Journal.htm
Philo, Stef, Ralph ... this is a call for help. We want to implement a simple
I2C bus to have at least 50kHz that we need to access our camera module.
- Claude
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Claude Baumann wrote:
> We started a new ambitious project. And this time, we are not certain that we
> will succeed. So, any help is welcome.
>
> http://www.convict.lu/Jeunes/RoboticsIntro.htm
> http://www.convict.lu/Jeunes/RCXCam/RCXCam_Journal.htm
>
> Philo, Stef, Ralph ... this is a call for help. We want to implement a simple
> I2C bus to have at least 50kHz that we need to access our camera module.
You could probably succeed in doing that - but why? The RCX doesn't have
enough memory to load even a single photo and it's teeny-tiny 8 bit CPU
will take an ETERNITY to process whatever it can get at.
Unless you have a very strange application in mind, you're going to need a
better computer than the RCX.
---------------------------- Steve Baker -------------------------
HomeEmail: <sjbaker1@airmail.net> WorkEmail: <sjbaker@link.com>
HomePage : http://www.sjbaker.org
Projects : http://plib.sf.net http://tuxaqfh.sf.net
http://tuxkart.sf.net http://prettypoly.sf.net
-----BEGIN GEEK CODE BLOCK-----
GCS d-- s:+ a+ C++++$ UL+++$ P--- L++++$ E--- W+++ N o+ K? w--- !O M-
V-- PS++ PE- Y-- PGP-- t+ 5 X R+++ tv b++ DI++ D G+ e++ h--(-) r+++ y++++
-----END GEEK CODE BLOCK-----
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In lugnet.robotics, Steve Baker <sjbaker1@airmail.net> wrote:
> Claude Baumann wrote:
> > We started a new ambitious project. And this time, we are not certain that we
> > will succeed. So, any help is welcome.
> >
> > http://www.convict.lu/Jeunes/RoboticsIntro.htm
> > http://www.convict.lu/Jeunes/RCXCam/RCXCam_Journal.htm
> >
> > Philo, Stef, Ralph ... this is a call for help. We want to implement a simple
> > I2C bus to have at least 50kHz that we need to access our camera module.
>
> You could probably succeed in doing that - but why? The RCX doesn't have
> enough memory to load even a single photo and it's teeny-tiny 8 bit CPU
> will take an ETERNITY to process whatever it can get at.
>
> Unless you have a very strange application in mind, you're going to need a
> better computer than the RCX.
>
> ---------------------------- Steve Baker -------------------------
Good reply.
1. The C3088 module allows framing, so we can reduce the data.
2. Why? Because we are in an educational environment, where the bulk is to
teach how to program micro-controllers with the background thought that if the
students learn how to operate the RCX/H8 with all its limitations, they are
disciplined in finding solutions under the conditions of limitations. So, that's
our pedagogical reflection. Those who have been at our web-site, know that we
already have proven what can reasonably be done with the RCX based on these
settings. The goal is to teach them how to address and operate a camera. If they
did this once in a simplified and primitive environment represented by the RCX,
they will know HOW this works and they will be well prepared for "real" computer
applications later in their studies or professional surroundings. Our point of
view is that things are easy, if you take solutions from the shelf and draw a
budget list with all the costly articles you need. Here we ask them : "That's
the stuff, you won't get anything else. Try to get that drop out of the citron."
3. Eternity? Depends on the data-size, the algorithms and the operating system.
If you look at our binaural sensor (under Ultimate Robolab pages) that is made
only by analog parts. We operate RCX sensor sampling at 36kHz for two channels
-together with data-storing in an array- and then a simplified cross-correlation
which takes about 2sec. for 2kB. Not famous, but try to find a similar solved
project at this low cost dimension. Because: the sensor works and we can build a
robot that turns its head towards you, if you are whistling a tune. No one would
have thought that this was possible with an 8-bit processor. When we started at
that time, people told us that you'd need at least an FPGA or 75Mips.
Our intention is to have sufficiently reduced picture data and only use very
fast algorithms. An optical mouse uses reduced "camera" data to deduce the
direction of motion...
Let's see.
This is challenging, and honestly I'm not sure that this time we will succeed.
But, it is such an interesting project.
By the way, I have worked out a real-time DFT algorithm that actually operates
the DFT for any data-size up to 500Hz with the RCX. This is not published yet
and works under Ultimate ROBOLAB. There are several tricks and it may appear
strange that it should be independant of the data size, but this is one of the
results of the algorithm.
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In lugnet.robotics, Claude Baumann wrote:
> We started a new ambitious project. And this time, we are not certain that we
> will succeed. So, any help is welcome.
>
> http://www.convict.lu/Jeunes/RoboticsIntro.htm
> http://www.convict.lu/Jeunes/RCXCam/RCXCam_Journal.htm
>
> Philo, Stef, Ralph ... this is a call for help. We want to implement a simple
> I2C bus to have at least 50kHz that we need to access our camera module.
>
> - Claude
Hello Claude,
What about this one?
http://mindsensors.com/index.php?module=pagemaster&PAGE_user_op=view_page&PAGE_id=33
There was also an RCX to I2C implementation a while ago in Elektor. If you want
I can find it again...
Philo
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In lugnet.robotics, Philippe Hurbain wrote:
> In lugnet.robotics, Claude Baumann wrote:
> > We started a new ambitious project. And this time, we are not certain that we
> > will succeed. So, any help is welcome.
> >
> > http://www.convict.lu/Jeunes/RoboticsIntro.htm
> > http://www.convict.lu/Jeunes/RCXCam/RCXCam_Journal.htm
> >
> > Philo, Stef, Ralph ... this is a call for help. We want to implement a simple
> > I2C bus to have at least 50kHz that we need to access our camera module.
> >
> > - Claude
>
> Hello Claude,
>
> What about this one?
> http://mindsensors.com/index.php?module=pagemaster&PAGE_user_op=view_page&PAGE_id=33
>
> There was also an RCX to I2C implementation a while ago in Elektor. If you want
> I can find it again...
>
> Philo
Hi Philo,
Merci beaucoup. I know this Elektor project (4/2002 German edition). Very well
made! But, as I understand it, the communication speed might be too slow.
However I'm not sure about this, because changing camera settings does only
require a few bytes transmission. I don't know if there is a lower limit for
I2C-comm with C3088. The upper limit is 400kHz.
Note that we can reconfigure the whole H8 to have digital instead of analog
inputs. And use the Port6 bits 0..2 to give us a High output state at low
impedance. The problem is to find a way to set a clear output Low state. (The
unpowered input port is at 10kOhm, which should be sufficient.) Hmmm.
Is there anyone who has experience with the Elektor circuit? What are the speed
limits?
The mindsensor.com one could be a good idea. Does anyone know more about the
speed? Or did I miss something?
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>
> The mindsensor.com one could be a good idea. Does anyone know more about the
> speed? Or did I miss something?
"Bit rate on the I2C bus is approximately 100KHz." But the overall limiting
factor is the use of IR serial link, 4800 bps at best...
Philo
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