SAKC board

Bas Wijnen wijnen at
Sat Jan 16 13:12:29 EST 2010


On Sat, Jan 16, 2010 at 08:31:35AM +0000, Wolfgang Spraul wrote:
> > In fact, if the marketing is done right (and that includes usable
> > out-of-the-box software), I think education could be a big market
> "usable out-of-the-box software" - point taken.

The point here is that while most physics teachers like technical stuff,
many are not programmers.  Using the things should not require much
learning for non-programmers.  The learning part should be about what is
observed, not how to get the measurement running. ;-)

> > if it's not too expensive.
> Which price point did you think about?

There are two options in the market at the moment.  For one I was unable
to find a price, the other costs €295, and I heard that's the cheap one.
I think it should be possible to beat them on price. ;-)

Anyway, as I write below, I think it makes sense to combine it with a
NanoNote.  To keep the combination cheap enough may be slightly harder.

> Somehow Carlos and I are crazy enough that we are trying to hit a 49
> USD sales price :-) But this might be just totally impossible, let's
> see what the components alone cost.

Even if it gets to $100 it will still be very cheap compared to other
options for schools.

> > A huge bonus would be if current sensors could be attached to the
> > board (shouldn't be hard).  The current solutions are all very closed 
> Definitely, please let us know in more detail which current sensors
> you have in mind and how you would want to attach them.

One system uses british telecom plugs for their sensors.  From
> The 631A and 631B plugs are also used for connecting sensors to
> interfaces for computer based measurements in educational
> environments, the former for connecting analogue sensors and the
> latter for digital sensors. Companies using these plugs include
> Vernier, TI and Casio, for interfaces connecting to their graphical
> calculators, and in the Netherlands CMA. They all use the same
> pinning.

The other system is from Pasco (  They use 5mm
stereo jack plugs for their digital sensors, and 5-pin DIN plugs for
analog sensors.

All sensors have pins for ground and power and signal, where power is
-10, +5, or +10V (depending on the sensor) and signal has the same range
(-10..+10 or 0..5).

Many newer sensors directly plug into a USB port (which means they also
do their own A-D conversion).  I have no idea about their protocols, but
it should be fairly easy to reverse-engineer it.  Especially if USB-host
capability is added to the NanoNote, and it becomes a sniffing hub. :-)

> In general - Where should we collect feedback for SAKC?
> I am proposing two places:
> 1. The 'Issues' system of our projects server at
> 2. The 'Discussion' page on the SAKC wiki homepage at
> Which one is better? Some other way?
> I am probably leaning towards the wiki discussion page, if I hear nothing
> back I will just add links to relevant mails to that page.

Personally I'm checking my e-mail, and not much else.  So I would want
to have something which allows e-mail notifications.  AFAIK the wiki

> > I know I'm not the only teacher who thinks that's
> > against the spirit of education.
> For sure. Which institution do you teach at? Can you point other interested
> teachers to this project?

At a high school.  I don't think pointing other teachers here already is
a good idea.  In fact, I think I should not point them to it until it is
completely finished.  Otherwise they will see that it is unfinished, and
may remember for years that it isn't usable, even if by then it is.

What it would need to do to be considered "usable" in this context is:
- Have a connection with a "normal" computer which can be used to
  control it.
- Have the possibility to connect digital (ttl) and analog (0/+5V and
  -10/+10V) sensors, and get measurements from them into the desktop
- Have the possibility to connect digital actuators (0/5V outputs).
- Have software for the desktop computer which makes it easy to do the
  measurements and handle the results.

Now if that's all it does, I'm not really interested. ;-)  All schools
already have things which do this, and while the software is annoying,
it does work most of the time.  So here's a list of features I'd like to
see, which would make it not just usable, but really good:
- The software should have a hackable interface, which invites the user
  to try new things.
- The board should be able to run without external power and with only a
  NanoNote to control it.  The combination should be so small that it's
  easy to carry to a place where no power sockets are available.
- The desktop software to prepare such a "remote" measurement should be
  intuitive.  The NanoNote should have a similar interface, so that
  non-programmers have no trouble doing such measurements.
- The logic on the board should be used to do better measurements.  This
  means it should be able to record times of signal edges with high
  precision, and it should be able to use the outputs in a pre-programmed
  way to allow building clamping systems (keep for example the voltage
  at a specified level and record the adjustments that are needed to do
- An analog output would be nice.  Especially if it's a relatively
  high-power output, which can be used for example to set the intensity
  of a lamp.

There are probably other things, but this is what just came up.  Are
there things in the list which will certainly not be possible?
Obviously the software on the desktop computer is no problem, I'll
probably write it myself. :-)

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