Success at Last!

Not this first part as Jan never has a failure!

Two ingredient scones.   I think one of the ingredients is self-raising flour.  Doesn't particularly matter as they were delicious!  Me….. I can burn water.

For several weeks I've been very frustrated with the boat navigation project.  Initially I thought I required (and bought) two small solid state modules.  The BMP820 is supposed to detect barometric pressure, temperature and humidity.  Whilst the system recognised the module it never detected humidity and only intermittently detected the other two.  The second module was an IMU.  This has 9 axis gimbals and measures Roll, Pitch, Yawl and compass direction.  The module wasn't being detected by the system and after several weeks of effort I started to suspect it was defective.  I also discovered the IMU included a BMP820. 

Eventually I purchased a replacement IMU from another Aliexpress seller.  When this module arrived it also wasn't detected.  Obviously I had done something incorrect with the configuration.  A week later and totally frustrated; I ordered a 3rd IMU module.  This time from the USA.  Today it arrived from Hong Kong and after making the required connections it was immediately recognised!

 

BMP820 - GY91 IMU and the 3rd IMU that works.

I can now progress the project.

Meanwhile the courier delivered some Australian condoms.  I had ordered the extra large.

They are Chinese made condoms.  Too big for Australian   I'm going to use them in an effort to seal the nozzles of the adhesive tubes I use in the caulking gun.  Hopefully they will prevent the adhesive hardening in the tube thereby minimizing the current wastage.

Wet Week

The autumn rain was late this year, arriving at the beginning of winter. At one point we received an entire month of rain in one day.  We experienced some local flooding in the local area and one consequence of this was the loss of the internet on several occasions.  Hopefully after a week of solid rain things will now settle down. 

No bike rides.  Actually we have hardly left the house!  Much of my time has been spent on our grandson's yacht electronics system.

I suspect I've underestimated the size of the box required to contain the electronic components.  Old eyes and shaky hands has been making it difficult to fit everything into a small space.

It all has to fit!

His yacht has a 12V DC power system and I therefore required a 12V supply to test everything.  My solution was to use an old computer power supply (never throw anything away as it might prove useful one day).  Computer power supply system are designed to only produce power when they recognise a computer is attached.  This meant I needed to trick the power supply into thinking it was connected to a computer.

 

Now I had a 12V power source I could start the navigation box.

I've wired it with the incoming power going through the fuse first and then to the switch (green LED).  The logic is if there is no green light then it's likely either the fuse is blown or there is no power.  The volt and amp meter wasn't required, but I thought it was a nice touch.  I don't believe the amp meter is accurate as I previously had the Raspberry Pi running through my USB Meter and it was drawing 0.8 amps.

The next step was to attempt to squeeze all the components and wires into the box.

That proved to be a challenge.

To take some of the ancillary load (attached usb devices) away from the small Raspberry Pi I've fitted a powered four port USB Hub.  This means the majority of the USB devices get their data from the Raspberry Pi but their power comes from the hub.  The hub is powered separately by a large 12V-5V converter rated at 20 Amps (grossly overdesigned).  The Raspberry Pi is powered by a separate 12V-5V converter with a USB socket.  A second 12v-5V  USB socket has been included as a backup supply for the Raspberry Pi.  This means the Raspberry Pi has two separate backup sources of power. 

My attention has now turned to the software.  The operating system will be Openplotter and the navigation system OpenCPN.  A GPS dongle plugs into one of the USB ports and will provide the location.  A second USB port has a TV Tuner dongle attached.  The plan is to reconfigure this to accept AIS signals (Automatic Identification System).  AIS signals are transmitted by other vessels and will appear on the navigation screen.  When I visited NZ last year I gave our grandson the cable and instructions for making an AIS antenna.  There is also a combine BMP820/IMU module which provides temperature, barometric pressure, a compass, accelerometer and motion signals (roll, pitch, yawl).

Reading the OpenPlotter documentation suggests the setup will be relatively easy.  However my previous experience with other projects resulted in me finding this wasn't the case.