Raymarine ST60 Paddle Wheel Simulator

[nigelmercier]

There has been some discussion in other threads about my Raymarine ST60 Paddle Wheel Simulator. This device takes a GPS input and outputs square wave pulses that look like the output from a paddle-wheel. This output is plugged into the paddle-wheel input of a Raymarine Speed or Tridata device, thus alowing it to calculate True Wind etc. Tested with a Raymarine ST60, but other devices should work, even from other manufacturers.

I've put all the documentation for this online here. This comprises the code for the PIC microcontroller and the PCB layout. Ideally these would be opened with mikroC PRO for PIC (which is free up to 2K of program words) and DesignSpark PCB (which is totally free) respectively.

The purpose of this thread is to support anyone wanting to build one of these units, preferably not for discussion about the validity of using a GPS RMC signal in place of a paddle-wheel.

Note that I retain copyright for this design (with the exception of the NMEA input buffer which belongs to Angus McDoon). I am not currently in a position to manufacture boards for this, but I'm happy to allow someone else to do so; terms to be discussed. Similarly, if PBO want to do a feature, I'm happy to discuss this.

 

[rogerthebodger]

Thats interesting Nigel

Would that allow the NMEA 0830 speed message from a GSP module to drive a speed display instrument designed to receive the NMES 0830 paddle wheel message to display the GPS speed in the absence of a paddle wheel.

I have been looking for something like this for my little MOBO for a while and when I have the time I was going to used a development board I got from Angus a while ago.

 

[RichardS]

Thats interesting Nigel

Would that allow the NMEA 0830 speed message from a GSP module to drive a speed display instrument designed to receive the NMES 0830 paddle wheel message to display the GPS speed in the absence of a paddle wheel.

I have been looking for something like this for my little MOBO for a while and when I have the time I was going to used a development board I got from Angus a while ago.

I think that it generates the pulses from NMEA GPS output that can then be fed into an instrument designed to receive pulses from a paddlewheel rather than NMEA output from a paddlewheel.

Richard

 

[rogerthebodger]

I think that it generates the pulses from NMEA GPS output that can then be fed into an instrument designed to receive pulses from a paddlewheel rather than NMEA output from a paddlewheel.

Richard

OK then thks not quite what I am looking for.

 

[Colvic Watson]

Thats interesting Nigel

Would that allow the NMEA 0830 speed message from a GSP module to drive a speed display instrument designed to receive the NMES 0830 paddle wheel message to display the GPS speed in the absence of a paddle wheel.

I have been looking for something like this for my little MOBO for a while and when I have the time I was going to used a development board I got from Angus a while ago.

Yes I think that's what Nigel is saying - it takes NMEA GPS and turns it into paddle wheel language to plug straight into a Raymarine speed unit to fool it into thinking it's getting the input from the paddle wheel.

 

[rogerthebodger]

Yes I think that's what Nigel is saying - it takes NMEA GPS and turns it into paddle wheel language to plug straight into a Raymarine speed unit to fool it into thinking it's getting the input from the paddle wheel.

If that's the case it is close to what I need except I meed NMEA 0830 output and not seatalk which is what it think Raymarine uses

 

[RichardS]

Yes I think that's what Nigel is saying - it takes NMEA GPS and turns it into paddle wheel language to plug straight into a Raymarine speed unit to fool it into thinking it's getting the input from the paddle wheel.

Rogershaw is talking about an instrument that can receive NMEA messages from the paddle wheel.

But the usual Airmar/Raymarine paddlewheel language is a series of analogue pulses. If you want to use NMEA output from a paddle wheel this would be essentially the same as the speed sentence NMEA output from the GPS so I'm not sure why you would need a gizmo.

My Raymarine C60 speed display will take GPS output in Seatalk or NMEA (the C80 plotter converts NMEA into Seatalk) or will take analogue pulses from a paddlewheel or will take both. However it knows the difference and will use the analogue pulses for calculating True Wind or Distance Travelled but it won't use the Seatalk/NMEA input for these purposes. To do that you do indeed need Nigel's gizmo or the commercial one I am getting for Father's Day!

Richard

 

[rogerthebodger]

Rogershaw is talking about an instrument that can receive NMEA messages from the paddle wheel.

But the usual Airmar/Raymarine paddlewheel language is a series of analogue pulses. If you want to use NMEA output from a paddle wheel this would be essentially the same as the speed sentence NMEA output from the GPS so I'm not sure why you would need a gizmo.

My Raymarine C60 speed display will take GPS output in Seatalk or NMEA (the C80 plotter converts NMEA into Seatalk) or will take analogue pulses from a paddlewheel or will take both. However it knows the difference and will use the analogue pulses for calculating True Wind or Distance Travelled but it won't use the Seatalk/NMEA input for these purposes. To do that you do indeed need Nigel's gizmo or the commercial one I am getting for Father's Day!

Richard

OK Richard.

I have several SIMRAD IS11 display instruments. These are normally driven by a SIMRAD computer that takes the analogue signals from the water speed, depth and wind speed/direction and convert than to a NMEA 0830 message that the displays receive and display.

I wish to fit a speed display on a small MOBO I have but don't have a spare SIMRAD computer to paddle wheel sensor. So I was thinking of using the SOG output from a GPS puck to drive the SIMRAD display. Now the water speed NMEA message is different from the GPS SOG message so I need some way to convert the GPS SOG message to the message the SIMRAD speed display understands.

I do have a complete SIMRAD IS11 setup and my sail boat so I can get the message formats if they are different from standard message formats.

 

[nigelmercier]

... the water speed NMEA message is different from the GPS SOG message so I need some way to convert the GPS SOG message to the message the SIMRAD speed display understands...

Certainly possible, but not by the device under discussion.

 

[rogerthebodger]

Certainly possible, but not by the device under discussion.

Thks Nigel

My need to fire up my old 8031 assembler or read up on PIC's.

 

[Forty_Two]

Nigel, if you do decide to get some pcb's made i would buy one please.

Thanks Paul

 

[Forty_Two]

Nigel, I am in the process of building one of your devices, thanks for this by the way!

My ST60 Tridata has Red / Green / Screen for the speed wiring part of the transducer. Can you confirm which outputs from your circuit to connect to which colours please. I am retaining the temperature part as is which as I understand it is the Brown / White wiring.

Thanks, Paul

 

[RichardS]

Red .... the topmost terminal ... is the +ve power output which is sent to the paddlewheel. You won't need this if your gizmo is powered from elsewhere. I guess it's 12V but I'm not using it either so I haven't measured it.

Green ... the next one down is the pulsed input from the paddlewheel or paddlewheel mimic gizmo.

Ground .... the third one down is the screen / earth and connects to the gizmo either directly or in my case, via the general ground on the Seatalk system

The lowest two terminals of the 5 ... Brown and White ..... need to remain connected to the temp sensor part of the Airmar paddlewheel or bridged with a 10K resistor.

Richard

 

[Forty_Two]

Thanks Richard

 

[Danny]

Excuse my ignorance but what's NMEA 0830 that's mentioned in several of these posts?

 

[RichardS]

Excuse my ignorance but what's NMEA 0830 that's mentioned in several of these posts?

It's just a mis-spelling of 0183.

Richard

 

[Forty_Two]

I have built your paddle wheel simulator using standard components on a piece of veroboard.

Am testing it using an old Garmin GPS45 in simulation mode, tried it outputing 0183 v1.5 & v2.0. When this didn't work i downloaded a PC GPS simulator which shows the $GPRMC sentence & it's contents, so i know the speed is in the sentence.

After power up with no input the LED is Off & output not switching as expected.

After connecting the 0183 signal the output is a square wave with a period of around 2 secs in each state & a short
LED flash every 10/11 secs. When i remove the 0183 input the output stays the same & the LED continues the short flash every 10/11 secs. With both sources i get a nice pulse train on RA5 & a short LED flash every 10/11 seconds.

Calibrate mode works when i use the jumper (0v > RA0), continuous LED & correct freq on the output, nice square wave pulses no problem.

I started using the PC simulator (sending $GPRMC & checksum) as i thought the Garmin may not be fully compliant as its rather old, however that makes no difference.

I had no apparent trouble when i did the hex build & no issues flashing the PIC.

The hex file shows as 11,327 bytes on my PC, does that sound about right?

I just opened your project file in "mikroC Pro for PIC" & did the build. Then used "mikroProg Suite for PIC" with a Pickit3 programmer to flash the PIC before installing in your circuit.

I think i have proved the input & output to the PIC are ok with the above tests, so i am left with either an issue over my build of the hex file or some strange NMEA 0183 issue.

Thanks for any help, Paul

 

[nigelmercier]

I have never used a PICKit programmer, but I know you need to read up on configuration, especially for the configuration fuses.

The LED should flash each time a sentence is decoded, or on error (see source code). Normally this would be about 1Hz. My first thought is that the oscillator fuse is set wrong, but if the calibrate mode works at 5Kn, it can't be that.

I think my download included a hex file, and possibly configuration fuses.

 

[Forty_Two]

I have never used a PICKit programmer, but I know you need to read up on configuration, especially for the configuration fuses.

The LED should flash each time a sentence is decoded, or on error (see source code). Normally this would be about 1Hz. My first thought is that the oscillator fuse is set wrong, but if the calibrate mode works at 5Kn, it can't be that.

I think my download included a hex file, and possibly configuration fuses.

Thanks Nigel, no there was no hex file in your zip download.

I just loaded the hex into "mikroProg Suite" & the "Oscillator" setting is shown as "ECH -External Clock, High-Power mode:CLK" which doesn't seem right, i will try setting it to "INTOSC - I/O function on OSC1/CLKI".

MCU clock is shown as 16MHz in the project settings & you do have OSCON in the code for the setting the Osc to int & 16MHz so can't see why that setting is the way it is when i load the hex. Other bits seem to setup ok.

As you say it seems unlikely as the calibrate mode outputs ok. Should the LED be permanently on in Calibrate, i wasn't quite sure from the code?

I will try changing this setting in the morning.

Thanks, Paul

 

[nigelmercier]

Try "INTOSC - I/O function to ..." the one with the data I/O.

If you Compile and Build in mikroC it should switch to mikroProg with the right settings.