Introducing OpenPlotter hats!!!

[jim321]

Tomorrow is yesterday now..
patiently waiting

[Sailoog]

 

Ok, here we go: http://forum.openmarine.net/showthread.p...92#pid3692

Specifications, price and approx delivery time. Next week we will know a more accurate date and perhaps we will open pre-sales.

[Ze'K]

Awesome. Can't wait. This is perfect timing for me as my boat is on the hard right now. Thank you.

[CVL]

Hello Sailoog

This is really a great development.

Looking at the graphic, it looks as if not the whole GPIO-header is accessible on the Moitessier-Hat?

I looked at the technical specifications of the PDF, but couldn't find any indication.

As a matter of fact I need the :
GPIO 4 for 1W - this is quite normal for OP-users
GPIO 22 and 27 is needed by the PICO UPS
GPIO 24 for pulse counting of the paddle-wheel

the last can move to another GPIO as it is defined in the script, the others are fixed.

Are these GPIO's used by the GPS/AIS/IMU on the Moitessier hat, or are they free?

Thanks a lot!
Christian

[Rooney]

Hello Christian,
attached you'll find the pinout of the Moitessier HAT. GPIOs marked green are used by the Moitessier HAT itself, GPIOs marked red are available at the optional IO header and are for free use.
If multiple HATs are stacked, the Moitessier HAT needs to be on top, otherwise the GNSS patch antenna would not work. This is the reason why no 40 pin header is available on the PCB top layer.

Regards,
Rooney

[GSAtlantic]

GPIO 24 for pulse counting of the paddle-wheel

Christian

Hi Christian,

Would you be willing to share how you’ve integrated your paddle wheel?
Some code you’ve written yourself?  

I have an old set of Datamarine 200KHz instruments I’d love to integrate.

Thanks,

Geoff

[CVL]

Hello Christian,
attached you'll find the pinout of the Moitessier HAT. GPIOs marked green are used by the Moitessier HAT itself, GPIOs marked red are available at the optional IO header and are for free use.
If multiple HATs are stacked, the Moitessier HAT needs to be on top, otherwise the GNSS patch antenna would not work. This is the reason why no 40 pin header is available on the PCB top layer.

Regards,
Rooney

Hello Rooney

thank you for this information - even if it means that the integration of Moitessier in my setup will be a bit more complicated...

I had already reasoned that I would need an external antenna, as the Pi is stocked to far downstairs to get proper signal.

fair winds
Christian

---

Would you be willing to share how you’ve integrated your paddle wheel?
Some code you’ve written yourself? 

Hello Geoff,

yep, I felt adventurous and tried to do a bit of python-coding on myself. Not that I am expert - if anybody has a better idea how to transform pulses in speed measurement, I am glad to learn:

Code:

#!/usr/bin/python
import RPi.GPIO as GPIO
import time
import os

GPIO.setmode(GPIO.BCM)
GPIO.setup(24, GPIO.IN, pull_up_down = GPIO.PUD_UP)

path = "/var/run/nmea.fifo"
os.mkfifo(path)

fifo = open(path, "w")
fifo.write('$VWVHW,,,,,0,00,N,,K\r\n')
fifo.close()

impulse_count = 0
NUM_CYCLES = 10
Counter = 10
while 1:
   start = time.time()
   for impulse_count in range(NUM_CYCLES):
       GPIO.wait_for_edge(24, GPIO.FALLING)
   duration = time.time() - start

   Counter = Counter + 10
   distance = Counter / 54737
   distancer = round(distance,2)
   speed = 15.2047222222 / duration
   speedr = round(speed,2)
   nmea = '$VWVHW,,,,,' + str(speedr) + ',N,,K\r\n$VWVLW,,N,' + str(distancer) + ',N\r\n'

   fifo = open(path, "w")
   fifo.write(str(nmea))
   fifo.close()

   time.sleep(0.5)

GPIO.cleanup()

The code counts 10 pulses and measures the time it takes. The paddlewheel documentation for the VDO says it counts  54737 pulses per 1nm, so this gives a basis for calculating speed in knots.

Then the values are transformed into NMEA-sentences and piped via a FIFO to kplex, which sends the NMEA to the cockpit.

Code:

[file]
name=logge
filename=/var/run/nmea.fifo
direction=in
persist=yes
checksum=no
strict=no

The script is started from rc.local so it runs as root. Security concerns are not so high on a standalone-system

Certainly there are ways to do this in a more elegant fashion... but I am not really a programmer.
Hope it helps though.

fair winds
Christian

[GSAtlantic]

yep, I felt adventurous and tried to do a bit of python-coding on myself. Not that I am expert - if anybody has a better idea how to transform pulses in speed measurement, I am glad to learn:

Code:

#!/usr/bin/python
import RPi.GPIO as GPIO
import time
import os

GPIO.setmode(GPIO.BCM)
GPIO.setup(24, GPIO.IN, pull_up_down = GPIO.PUD_UP)

path = "/var/run/nmea.fifo"
os.mkfifo(path)

fifo = open(path, "w")
fifo.write('$VWVHW,,,,,0,00,N,,K\r\n')
fifo.close()

impulse_count = 0
NUM_CYCLES = 10
Counter = 10
while 1:
   start = time.time()
   for impulse_count in range(NUM_CYCLES):
       GPIO.wait_for_edge(24, GPIO.FALLING)
   duration = time.time() - start

   Counter = Counter + 10
   distance = Counter / 54737
   distancer = round(distance,2)
   speed = 15.2047222222 / duration
   speedr = round(speed,2)
   nmea = '$VWVHW,,,,,' + str(speedr) + ',N,,K\r\n$VWVLW,,N,' + str(distancer) + ',N\r\n'

   fifo = open(path, "w")
   fifo.write(str(nmea))
   fifo.close()

   time.sleep(0.5)

GPIO.cleanup()

The code counts 10 pulses and measures the time it takes. The paddlewheel documentation for the VDO says it counts  54737 pulses per 1nm, so this gives a basis for calculating speed in knots.

Then the values are transformed into NMEA-sentences and piped via a FIFO to kplex, which sends the NMEA to the cockpit.

Code:

[file]
name=logge
filename=/var/run/nmea.fifo
direction=in
persist=yes
checksum=no
strict=no

The script is started from rc.local so it runs as root. Security concerns are not so high on a standalone-system

Certainly there are ways to do this in a more elegant fashion... but I am not really a programmer.
Hope it helps though.

fair winds
Christian

Thank you for sharing Christian!  I may give this a go myself.

Much Appreciated!

Geoff

[Saqqara]

...If multiple HATs are stacked, the Moitessier HAT needs to be on top, otherwise the GNSS patch antenna would not work. This is the reason why no 40 pin header is available on the PCB top layer.

Regards,
Rooney

Anyone know of a prototyping board designed to be sandwiched in the middle?

Maybe that's the Slocum hat.

Joshua Slocum did not need such a hat to hook up lots of analog and digital sensors to alert for intruders. He merely sprinkled the deck with sharp tacks and waited for the barefoot natives boarding his boat at night to cry out in agony!

We Openplotter fans like to do things the complicated way.

[GSAtlantic]

Joshua Slocum did not need such a hat to hook up lots of analog and digital sensors to alert for intruders. He merely sprinkled the deck with sharp tacks and waited for the barefoot natives boarding his boat at night to cry out in agony!

We Openplotter fans like to do things the complicated way.

Saqqara,

Joshua Slocum put his hats on broomsticks out the port lights to make his crew appear larger and ward off boarders.

Either way... Hats are good!

Geoff