Investigating the Raspberry PI

The more I play with it, the more I like it... It's so small - and so cheap - and it is a real Linux system, based on Debian. It comes with Java. It runs from a small SD card (4Gb recommended minimum). All the info are available on the Raspberry PI web site.

Development config

Minimal config

The GPIO can be managed with PI4J, works like a charm. Example:

----------------------------------------------------
HARDWARE INFO
----------------------------------------------------
Serial Number     :  00000000a36c8782
CPU Revision      :  7
CPU Architecture  :  7
CPU Part          :  0xb76
CPU Temperature   :  49.8
CPU Core Voltage  :  1.2
MIPS              :  697.95
Processor         :  ARMv6-compatible processor rev 7 (v6l)
Hardware Revision :  000e
Is Hard Float ABI :  true
Board Type        :  ModelB_Rev2
----------------------------------------------------
MEMORY INFO
----------------------------------------------------
Total Memory      :  459505664
Used Memory       :  240529408
Free Memory       :  219484160
Shared Memory     :  0
Memory Buffers    :  20328448
Cached Memory     :  141778944
SDRAM_C Voltage   :  1.2
SDRAM_I Voltage   :  1.2
SDRAM_P Voltage   :  1.23
----------------------------------------------------
OPERATING SYSTEM INFO
----------------------------------------------------
OS Name           :  Linux
OS Version        :  3.6.11+
OS Architecture   :  arm
OS Firmware Build :  4f9d19896166f46a3255801bc1834561bf092732 (clean) (release)
OS Firmware Date  :  Sep  1 2013 23:31:02
----------------------------------------------------
JAVA ENVIRONMENT INFO
----------------------------------------------------
Java Vendor       :  Oracle Corporation
Java Vendor URL   :  http://java.oracle.com/
Java Version      :  1.7.0_40
Java VM           :  Java HotSpot(TM) Client VM
Java Runtime      :  Java(TM) SE Runtime Environment
----------------------------------------------------
NETWORK INFO
----------------------------------------------------
Hostname          :  raspberrypi
IP Addresses      :  192.168.1.251
FQDN              :  raspberrypi.att.net
Nameserver        :  192.168.1.254
----------------------------------------------------
CODEC INFO
----------------------------------------------------
H264 Codec Enabled:  true
MPG2 Codec Enabled:  false
WVC1 Codec Enabled:  false
----------------------------------------------------
CLOCK INFO
----------------------------------------------------
ARM Frequency     :  700000000
CORE Frequency    :  250000000
H264 Frequency    :  0
ISP Frequency     :  250000000
V3D Frequency     :  250000000
UART Frequency    :  3000000
PWM Frequency     :  0
EMMC Frequency    :  100000000
Pixel Frequency   :  108000000
VEC Frequency     :  0
HDMI Frequency    :  163683000
DPI Frequency     :  0

The first goal will be to have such a device running in the chart table, reading the NMEA Data (connected on the NMEA Station through its serial port, read with GPIO, as mentioned above), and re-broadcasting the data on HTTP, TCP or UDP. The re-broadcasting part has been tested (see here), with logged data.
Next:

• Connect the serial port, and read it from Pi4J
• Create an ad-hoc network FROM the Raspberry PI

This way, several applications can use the NMEA Data, simultaneously. It has been tested with the NMEA Console, and OpenCPN, with TCP and UDP. The HTTP re-broadcast can be used from an HTML5 browser, from a laptop or a tablet, connected on the boat's ad-hoc network.

HTML5 NMEA Console, on a tablet

South California Free Anchorages

Working on it. There is this site, quite interesting, and I'm trying to use Google Maps as well.

View Free anchorages in a larger map

More to come soon, stay tuned.

Part of Navigatrix!

As of July 3, 2013, the Weather Wizard is part of Navigatrix! Cool recognition ;0). And the user manual is now available directly from the soft, as a pdf file, downloadable from the Internet. Lulu.com still provides the binded version of the document.

Spot GRIB Request

saildocs provides support for the Spot GRIB requests. Spot requests returns forecasts for a given location. Let's say you just dropped the hook, and you want to know what your night is going to look like...
If you send an email to query@saildocs.com, with a body like this:

 send spot:37.5N,122.5W|5,3|PRMSL,WIND,RAIN

, you will receive a response like that one:

Data extracted from file gfs130704-12z.grb dated 2013/07/04 16:52:56
request code: spot:37.5N,122.5W|5,3|PRMSL,WIND,RAIN

Forecast for 37°30N 122°30W (see notes below)
Date  Time  PRESS  WIND DIR RAIN
        utc    hPa  kts deg mm/h
----------- ------ ----- --- ----
07-05 00:00 1005.7  9.8 288  0.0
07-05 03:00 1005.7  11.5 297  0.0
07-05 06:00 1006.8  12.9 302  0.0
07-05 09:00 1006.7  13.0 303  0.0
07-05 12:00 1006.7  12.6 303  0.0
07-05 15:00 1007.0  11.7 299  0.0
07-05 18:00 1007.7  10.3 280  0.0
07-05 21:00 1007.2  11.4 270  0.0
... etc

This is "human readable", as they call it, but not that catchy, hey?
The cool thing is that this content can be parsed, using basic regular expressions.
If you drop the content of the request's response in the box below, you will have a chance to render it visually.
See in full
The browser you use must support HTML5 for that.

Reviving the Weather Wizard Applet

It needs to be signed (to be trusted)..., but give it a try: here (in full), or below (in small).

This demonstrates a small subset of the features of the Weather Wizard. There is no GRIB, no routing, no possibility to save anything.
But that gives you a taste of the possibilities.

The applet is signed. That means it wants to get out of the Sun sandbox. Namely, it wants to read the faxes from an external website.
Once you have selected your composite (from the top drop-down list), do not forget to hit the "Go" button...

Version(s) 3.0.1.3

Released today the version 3.0.1.3 of the Weather Wizard, the Navigation Desktop, and the Polar Smoother.
The release includes some bug fixes, cosmetic improvements, and a decomposition of the deviation curve (in the NMEA Console), as shown below.

Click the image to enlarge.

And with the NMEA re-broadcast, the Navigation Console works like a charm with OpenCPN 3.1.1328.

OpenCPN 3.1.1328 released

A new beta of OpenCPN has just been released, it supports other channels than Serial for the NMEA data input. TCP, UDP, GPSD... That means that if you read the NMEA port from the Console, you can re-broadcast them on another channel that OpenCPN can listen to; no more Serial port access conflict, the two applications can run simultaneously, that is very cool. That also means that when you replay logged data in the console, you can visualize them in OpenCPN too. Even better!
AIS Data can also be read this way. The San Francisco Bay traffic can be seen by using a TCP connection on 207.7.148.216, port 9009

Custom Micro Pattern

The micro patterns rely on two main features:

• A background
• GRIB Smoothing

The GRIB Smoothing is not a problem, and the value it can take are now available in the pattern editor.
The problem can come from the backgrounds. Up to now, they refer to an image, part of a jar, accessed through a getResource() method.
In order for the user to be able to come up with his own patterns, there is now "protocol" for the background.

Click the image to enlarge it. Notice in the fax URL (a background is just a non-transparent fax), it begins with ext-resource://.
Whatever is after that is the URL of the image you want to set as a background. In this case, it is picked up in the resources directory. But it can come from the web as well, it just has to begin with http://...
Notice beside the "Projection" drop down list, you now also have the possibility not to display the chart contour.
The GRIB smoothing parameters we talked about before are the 2 last parameters at the bottom of the dialog displayed above.

Micro Patterns

Combining the chart backgrounds and the GRIB smoothing, we can come up with a local pattern, which can actually make some sense, specially for local conditions (wind and kite surfers might be interested).

The image above is the display of the following request:

  GFS:42N,32N,128W,116W|1,1|0,3..168|PRMSL,WIND,HGT500

It is displayed with a GRIB 2D smoothing of 6 (cells are 10x10 nm) and a time smoothing of 3 (one frame every hour). The total time is one week, that makes 168 frames.
At the entrance of the San Francisco Bay, the wind goes from WSW on Wednesday at 06:00 UTC, to South and 12:00 UTC, to North on Friday at 00:00 UTC. Interesting...
This feature - and the associated background - will be available soon, in the next patch version of the software.

Digital Image

This is indeed what you can call a digital image... Just take a step back in case it is not obvious to you. Or forward actually, it depends on what you missed. ;0)
Click here to see it in full.
You can do your own, just go to text-image.com.