Interfacing to the tacktick NMEA unit
max72
Posts: 1,155
Following a discussion in another thread I'm starting a new one.
The scope is to find out ways to interface to the tacktick NMEA unit.
The starting part is at page 3:
http://forums.parallax.com/showthread.php?115552-GPS-Datalogger-%28Using-Google-Earth%29/page3
Sailing Eric pointed that tacktick is now part of raymarine, so documentation is more difficult to find.
I have an official pdf from the old web site so I'm not sure I can upload it.
Anyway the unit has a NMEA out +/- and a ground pin available for connection to external instrumentation.
I don't know the baud rate, basic baud rate is 4800, but often units transmit at 9600, so the only way is to try.
Nmea out + can be used as serial, but in my opinion using +/- with an RS485 transceiver and a common ground would be a nice option.
The RS485 will take care of interfacing to the signal levels of the unit, and isolating our micro from the rest of the instrumentation.
The serial side of the transceiver can be chosen to have 3.3 or 5V signal level.
I have little experience with Basic stamp, but the propeller and the GPS IO mini object could be tailored to work with little effort.
Obviously reality usually strikes back, so any suggestion is welcome.
Massimo
The scope is to find out ways to interface to the tacktick NMEA unit.
The starting part is at page 3:
http://forums.parallax.com/showthread.php?115552-GPS-Datalogger-%28Using-Google-Earth%29/page3
Sailing Eric pointed that tacktick is now part of raymarine, so documentation is more difficult to find.
I have an official pdf from the old web site so I'm not sure I can upload it.
Anyway the unit has a NMEA out +/- and a ground pin available for connection to external instrumentation.
I don't know the baud rate, basic baud rate is 4800, but often units transmit at 9600, so the only way is to try.
Nmea out + can be used as serial, but in my opinion using +/- with an RS485 transceiver and a common ground would be a nice option.
The RS485 will take care of interfacing to the signal levels of the unit, and isolating our micro from the rest of the instrumentation.
The serial side of the transceiver can be chosen to have 3.3 or 5V signal level.
I have little experience with Basic stamp, but the propeller and the GPS IO mini object could be tailored to work with little effort.
Obviously reality usually strikes back, so any suggestion is welcome.
Massimo
Comments
If you use the optoisolator, then you can invert easily by placing the led around either way. The output transistor is just a 10K from 3v3 to collector, with emitter to prop ground.
Hope this helps.
How do you find the tacktick instruments? They were quite expensive, but that was a few years ago. BTW C-Map is now available on the iPad so I hope/expect it to be available on android soon - I have a Xoom.
Postedit
I have just read the other thread, so here is some more info for those that asked there.
I used the prop because I wanted to get at least 4 NEMA inputs. The prop makes this simple as you can use 4 FullDuplexSerial drivers in 4 cogs (pocessor cores for the stamp guys) or you can use the 4 port driver in the obex which uses 1 cog. You can then use other cogs to display the data to a TV - I bought a car reversing LCD 4.3" unit that takes composite video (TV) input for $26 on eBay, or you can use the propplug or equivalent to send the data to a PC or Laptop via USB, or both simultaneously. Currently my data parsing was done on the Laptop in VB6 but could be easily translated to spin which is my eventual aim. My current VB program only performs one instrument at a time. I have decoded the Navman Depth/Speed/Log, Wind Speed/Direction, and the Chartplotter GPS/etc. I don't recall decoding the Autopilot.
I have a small regatta system for a sailing boat, and it uses a solid state anemometer for wind data.
The boat has not power rails, so I use a 12V battery to power the anemometer and send the data to the display via xbee. The anemometer trasmits at 9600 baud, and enters on the prop pin (via the usual resistor).
The main unit gets wind reading, parses GPS data from an internal module and takes care of the navigation and the regatta related calculations. It is a slow work in progress, but it now handles waypoints, start line and count down, calculates true wind and offers target speed and angle for the calculated data. Everything is logged on an SD.
I would like to use the same display on a tackitck powered boat of a friend, so the trasmitting unit should be adapted to parse the data.
I searched the web for NMEA and it looks that the standard has a lot of forks:
http://www.actisense.com/Downloads/TechTalk/NMEA%200183/The%20NMEA%200183%20Information%20Sheet.pdf
It's good to know that I'm not allone in this....
On my system I have windspeed and apparent wind angle from the anemometer, boatspeed and course over ground from the GPS. From this, the other data can be calculated.
@max72
You have about the system that I was dreaming of building! First target is logging data to build up reference. Later I would like to add a display, with the possibillity to compare current speed and anglg with targets; or changing wind directions. I do have the problem of missing windshifts..... How do you present your
From my Tacktick Wireless Interface I also have an "old" pdf (UU046 - rev11 1051315), but it only states which of the connections is NMEA out or in, and power; nothing about BAUD rates. I was refering to slow answering when I mentioned the acquisition by Raymarine.
@Cluso
My choice for Tacktick was governed by the option of presenting VMG on the display (communication of the wireless interface with my Garmin GPS over NMEA) as I was struggling in the upwind leg to keep up with competition. Tacktick helped me to see that I was focussing on true boat speed too much where I should try to sail higher. My performance has improved strongly this summer :-D
Is it possible with the prop to fully program the TV; showing watever you want?? That would be awesome!
To your opinion, what would I need to build a system like that?
1 Propeller chip $7.99
2 PropStick USB (32210 $49.99) or Propeller Proto Board USB (32812 $29.99) Both programming and datastorage over the same USB?
Or educationkit 32306? $99.99
Or Gadgetgangster 32208 $49.99
Anything else?
Thanks
Eric
At the moment I have a true wind direction on the display, besides true speed, vmg and angle to wind (both mine and target) but I have not a "previous angle" info.
Having the Xbee I was considering the possibility to create a kind of remote control for some functions. Possible options: countdown, mark position, store current wind, switch display mode, ..?
We are sailing on a platu25, which is closer to a daggerboard than to a sailing boat, so free time to control the instrument is seldom available, and at the moment I'm keeping infos to the minimum.
Displays are a real bottleneck, because direct sunlight is a problem. I found an extremely expensive transflective display which is great (edip series).
If you are ready to jump to the propeller boat (!!) for your first task I would suggest the prop platform. It already has micro SD card on board, so you only need to interface to the serial data of the NMEA unit. It also has the USB to serial part to interface/program directly from your PC.
There are objects to save to SD and to parse GPS serial data, so data logging would be achievable with "little" effort. Consider all the boards have linear regulators, so if you drain too much current they will heat up a lot. In the case of a data logger this is not a problem, but you'll want more and more very soon...
You'll need a proto board where placing the 485 tranceiver or the protection resistors.
You can use the same prop to drive display (serial, VDA, TV), do calculations and so on. With display the bottleneck is memory for the buffer, but we can survive..
The Prop is a great micro, but is different from BS, and the 8 COGs concept requires a little bit of time to get started, so whenever you need help ask..
TV can be any display you buy and you can use just text or pics. There are plenty of demos in the obex - only requires 3 pins and 3 resistors. What you are doing is not complex, so to speak, so you should not have a hub memory problem. The screen will most likely need to be located out of driect and indirect sunlight. Displaying test is easy and you can use the large prop fonts at least for starters.
The advantage of the prop is that each major task you want to perform can be done in a separate cog (processor) so you do not have to worry about interrupts and timings.
I have cheap pcb modules for microSD etc. I have not built an optoisolator module though - wired mine on breadboard.
Having been messing around with a Seatalk interface using the prop this past summer has been lots of fun. I am sure that your best approach is to use the prop and make a very simple program to get the data into a PC. Once you have this working, then you can begin to migrate functions back into the prop. I think that the 8 cogs is the best solution. you can use one as a VGA display driver, one for the link to the pc, one for the SD card to record, one for the NMEA, etc.,,. and one for seatalk if you any older Raymarine stuff on board. I just used a cheap FET and a couple of resistors to interface the seatalk data. The seatalk data seemed to be just fine with that. The USB port on the prop can send high speed serial data back into the PC for display either on the serial debugger or directly into your own program. I find this the simplest way to debug stuff, so it actually goes way up in speed into the PC, 115k. You can see some older versions of my seatalk program at the links below. The first is the main youtube channel, the second is one of the videos showing the seatalk stuff. Do you know of any links for 'open source' reverse engineered version of these tacktick protocals? FYI, I used a cheap (200) LED based Flat screen TV with a VGA input. The real issue is brightness outside. most can not been seen.
what exactly are you planning to do with the data?
http://www.youtube.com/user/waltsailing2009
http://www.youtube.com/user/waltsailing2009#p/u/19/XHJnQscSXxU
Regards,
Walt
At first I wanted to keep things simple and choose the Basic Stamp for logging data (also because of the board battery) for later analysis, but the propeller has such interesting options...
Now I would also like to
2 add a data screen
3 compare current boatspeed with target boat speed (best in history under similar conditions; thank you Max72)
4 detect and display windshifts, comparing current wind angle to running average (if 3 is possible, this should be possible too)
5 seatalk? hmm I have an old depthsounder I could add as well (not very important for me as I mostly sail in well known waters; thank you Walt)
Many options are taken care of by the GPS (waypoints, course to waypoint, time to waypoint etc) but echo to a screen could improve readability....
Water resisance might be an issue for the screen. Although my Dehler Dehlya22 has a small cabin, it can still be wet due to spray. The prop can be stored in a dry container I presume.
First things first:
1 choose a propeller-set,
Am I right that the Propeller (Propeller chip $7.99 +Propeller Proto Board USB 32812 $29.99) is so much cheaper than the Basic Stamp (BS2 $49.00 + board $19.99 + memory stick data logger $34.99 + USB-RS232 $16.99)??? What am I missing??
2 connect to the Tacktick
3 log data
Eric
http://www.parallax.com/StoreSearchResults/tabid/768/List/0/SortField/4/ProductID/708/Default.aspx?txtSearch=board+enclosure
While not water tight it survived even moderate rains.
As you can see from the picture acrylic is not the best solution (too brittle.. tt 25+ knots the shocks are frequent).
All you are planning is possible with the prop, taking advantage of the parallel approach.
Regarding your questions:
1) If you get a protoboard you have all you need with the only exception of the SD card adapter (there are many available, at parallax you can find them at 15$, but there are even cheaper approach, more hacker oriented).
2) Start redirecting the serial data to the teminal (see waltsailing post), after finding the right protocol you can use a NMEA parser like GPS_IO_mini, you can download from the obex http://obex.parallax.com/objects/225/
I posted questions about a serial redirection issue here, but the base redirection code is here:
http://forums.parallax.com/showthread.php?136431-Serial-objects-question
3) Get one of two main SD handling objects
http://obex.parallax.com/objects/92/
http://obex.parallax.com/objects/619/
A great appnote is here:
http://www.parallaxsemiconductor.com/an006
and don't forget....
4) mixing 2 and 3
For a tv screen try a car reversing monitor for abt $22-$25 for 3.5 or 4.3" on ebay. You will need 3 or 4 resistors for this (191r to gnd) plus cable - see the demoboard schematic. You can get waterproof keyboards rollup variety that work in ps2 mode as well as usb. ps2 is simple circuit and there is a driver in obex.
Ok lets get started!
If the protoboard gets me started for $30 (€32,= in the Netherlands, wonder about the exchange rate they use), I know what I want for Christmas ;-)
Max72, thanks for the links, saves me a lot of time looking for the right documents.
I have some studying to do....
Eric
Newbee on a steep learning curve
I built my Nema interfaces while waiting for my prop boards. I didn't know a lot about the prop so chose to use the optoisolator route as suggested in the Nema spec. However, for reading with the prop, just use a 4K7 series resistor as this will protect the prop. I would think that even a 10K should be fine. Start with the FullDuplexSerial object from the obex. Initially use two copies, one for outputting to the PST (Parallax Serial Terminal) on the pc using 115,200 baud over USB.
However, as a primer, do the tutorials that come with PropTool first. There is a sticky at the top of the prop forum that has links to lots of beginner info. If you are stuck, just ask.
This week, the postman had a package for me :-)
I have it connected, first programming done. Started to work through the Tutorial, as suggested by Cluso99. That is defenitely necessary! I'm afraid I will need some time before I understand the projects in OBEX. I had a glance at the FullDuplexSerial, but that's quite complicated :-(
Questions I still have:
1.Can anyone explain in more detail how I should connect the NMEA-out (Tacktick) with the Prop? I dont get the "inverted" connection Chris Savage mentioned, and where to put the 22K resistor...
2. Would it be possible to use the mini-USB to connect a USB-stick for data logging? I noticed it is used for by "FemtoBasic_Propterminal" for output as well
Thanks again for your help,
Eric
newbee, novice, greenhorn...
1. Just connect the NMEA out from the tacktick to a prop input pin via the 22K resistor (in series). 22K is rather high IMHO but should be fine at 4800 baud. The inversion can be done by the FDX settings if required (which is most likely).
2. No. The FT232 only acts as a USB slave and you would require a master.
You can add an SD or microSD card to your ProtoBoard simply. There are a few choices...
* Buy an SD to microSD converter card (it is an SD card that takes a microSD internally. Then solder the 6 wires (IIRC you can use RA pin stakes) to your pcb. You will need a 10K pullup on the -CS pin and either a 0.1uf and 10uF across the power and gnd pins at the card end or a 1uF Tantalum should probably also work instead.
* Buy a converter pcb that has a pin header and the SD or microSd socket. I have one with the caps and an optional 3v3 regulator for 5Vin (see my web link below)
One of the most powerful features of the propeller is the possibility to use object from the obex.
Some of them are quite "easy" to understand and a great learning source.
Others are showing the power of the chip in skilled hands... the code is first quality, but far from easy to understand. Examples are *any* serial, float (f32 and friends), graphics, 32 servo control in 1 cog, SD card access, and many, many others.
The nice thing is others already coded it for us...
Resistor: Usually you place a resistor in series between the prop pin and the external unit, to limit the corrent draw. It really depends on the voltage used on the NMEA unit. It is probably 5V, but Chris assumed a conservative 12V.
If you have a scope the best solution would be to check if the signals are 12V or 5V.
Anyway the series resistors limits the current across the prop pins. The higher the resistance the lower the current across the pins, but the max baud rate lowers. As Cluso said at 4800 baud it is ok, if the baud rate is higher the signal would be unusable.
Probably a 2.2k or a 4.7k is a good trade off.
The "inverted" option is done via the object when you initialize it.
If you have a GPS connected to the unit start with the GPS io mini here: http://obex.parallax.com/objects/225/
If you get garbage try to adapt the "mode" parameter and the baud rate. (maybe increase the stack space in the object..)
Or use a serial mirror test program to verify the NMEA stings are arriving correctly.
This is a possible solution, adapt the port number and the baud to you needs. Open a serial terminal and check if you can read the strings... It should work..
Serial mirror_NMEA - Archive [Date 2011.12.19 Time 14.40].zip
For data logging, I think the best solution would be to use a SD card. If you feel a hacker you can use a microSD with the adapter, and use the adapter as a socket. Simply solder the wires to the pads. There are examples on the web. Or better, use a SD adapter.
I had succes with SD card readers soldered on a veroboard (the pin spacing is almost perfect). The objects for SD acces are great.
The USB port is used to output serial data to the PC, so you cold be able to log to the PC, but SD cards are a great way.
Massimo
Still a lot I don't have worked out......
So far I have:
- purchased 1 protoboard
- connected it to my laptop, and
- programmed it following the manual
- worked through the tutorial in the help files (designed for the Demo board, so I don't have all the LEDs installed)
So, a basic understanding has been developed...
Next:
1. Connect Tacktick to Propeller
2. Get readout of the NMEA
1. I set up the TackTick and GPS at home, and tried to measure the NMEA output with my Voltmeter. I see a pulse every second of about 2V, but maybe my (analogous) instrument is too slow. I don't expect it to be 12V however.
Would this be a correct way to connect the Tacktick to the Prop:
Is there a preferred pin to use for this connection, keeping in mind the programming to use (see below)?
2. How do I visualize the NMEA coming in?
I downloaded the suggested Spin documents, but they are too complicated just now to understand.
GPS to VGA is helpfull when you connect a VGA monitor I presume, but I don't have that available (yet) Is Propterminal usefull to print the input on PCscreen?
Or does Serial Mirror / Full Duplex Serial relay back to the pc?
I see it uses pin 26 and 27 for in/out? That would be the easiest pins to connect, I think?
Thanks for any help (again).
Eric
You are supposed to have the same ground on nmea unit and prop, so it should be safer. nmea- has a variable voltage and you are not supposed to ground it. The exception is if you use a separate power supply and no common ground, but this is not the case.
Use a free pin, on a protoboard 0-27 are ok.
You can adapt a VGA out to a terminal out. Use "parallax serial terminal" object to send data to the terminal. the "start" only needs the baud rate, everything else is done for you.
try to play with the terminal alone, to get used.
with serial mirror debug starts the serial terminal, while comm2 starts the other serial port. I use the 5 ports object, but Full duplex serial is similar. In my case I use pins 26 and 27. -1 excludes a pin. I'm using port 0 of the 4 available. I start the other 3 as fake for better timing. The last two parameters of the addport are mode (inverted or not), and the baud rate.
Try mode 1 and 0. Baud rate 4800 and 9600. If you get garbage you are close, but the baud rate is wrong. if RX is flashing too much change mode.
-> comm2.AddPort(0,26,27,-1,-1,0,%0,115200)
Massimo
Nmea standard says you are supposed to drive not more than 2mA from the line, so if you have a 4k resistor it could be safer...
Massimo
I would suggest you get an opto isolator or an FET and wire up a circuit that will protect your propeller just in case. The inputs are supposed to be low voltage, and what i ended up doing is using an FET with a couple of resistors. For looking at the signals, I used the propscope. Good for this type of stuff and its USB and works fine with the PC out on the boat (yes, its small enough to take out on the sailboat in the tool box for debugging stuff). This way I was able to see that the data which was being shipped over single ended sea-talk was in fact being interfaced correctly to the propeller. The circuit I used was nothing more than an inverting FET, with a 10k tied to the seatalk and then to the gate. A seperate 10k was tied to the prop 3.3 volts. The other side went to the drain. The souce was tied to ground. The drain was then connected to an input pin of the prop. I used one of their demo boards with the prototype area. http://www.fairchildsemi.com/ds/2N/2N7000.pdf. This is the FET I used, the connections are shown in figure 11.
http://youtu.be/nGGVK2JuE_M
The above link at the end shows the actual implementation. I think i didnt post this link last time. It is an even earlier version of the program.
Others have suggested using a opto for the interface and that is also a good idea. In my case, the power was from a wall wart that runs the propeller prototype board, so i am plugging that in to 110 VAC. Not the most efficent solution, on a sail boat, but with solar panels and an inverter it is the simplest and doesnt tax the system.
Couple of things that I found helpful were to get the data into a PC. And, then into Visual Basic. Visual Basic is easy to programs to process the data. Before trying to do anything with it on the propeller, I would make sure that you can see data in the PC all the time. The same USB serial cable used to program the propeller is used for the serial data into the Visual Basic Program, and into the propeller serial terminal. You have to switch between them, but having the data in a human readable text string format that you can just display is well worth the trouble because without it you will be stuck without special purpose debugging tools, scopes, logic state analyzers etc., Once you get it into the PC and are able to understand things, then you can and start developing things in the propeller which are beyond the gettting the data into the propeller. Things like recording to the USB stick, displaying on the VGA or other display. VGA displays are cheap and the way to go. But, the LED TV I used had the best brightness i have found so far. Short of some multi-thousand dollar ones that are for marine. (Way over priced), but they are water proof and have the brightness you need.
Have fun, the prop took a few weeks to figure out, and you should get all the books they sell on it, as they will help you out a lot. Its not quite as simple as the basic stamp. Having programmed the BS1, BS2, a number of PICs, and other systems, the propeller is unique but well worth the trouble to learn.
Regards,
Walt
CON rxPin = 31 'serial txPin = 30 baud = 115200 OBJ fdx : "FullDuplexSerial" 'for debugging nema : "FullDuplexSerial" 'for tacktick PUB Main waitcnt(clkfreq*5 + cnt) 'delay (5 secs) to get terminal program running (if required) ' fdx.start(rxPin,txPin,0,baud) 'start serial driver to PC fdx.start(rxPin,txPin,0,baud) 'start serial driver to PC fdx.tx(0) 'cls fdx.str(string("Just a start message",13)) nema.start(27,26,0,4800) 'start serial driver from nema (connect via 10K to P27) 'if the above does not see the data using the nema.rx etc, try changing the 0 to use inverted logic - see the source for correct parameter values) repeat fdx.tx(nema.rxbyte) 'echo to the pc every character readI have not checked this code, but it is the basics to just test that you are seeing the data. Once you see it, then you can go from there.
Love your video Walt. A laptop is not such a good idea on my 22ft boat; it's bumpy and might get quite wet..
Check my video: http://www.youtube.com/watch?v=wu6G-7Lofwc I cross the startline 1st at 24sec :-)
Max, I tried your code, but when compiling I get the message "expected a subroutine name" at the end at "fdx.tx(nema.rxbyte)"
Also, getting ready for this test, I soldered a wire to P30 to receive the NMEA-data. You use 30 and 31 for txPin and rxPin; is that important, can I assign other pins there, or do I change the wire to P27?
This code will echo to the PC, how will see it? Use Propterminal? Or will it open a window itself?
I found a variable resistor to use for the NMEA in; my idea was to start high and slowly adjust down until I see data coming in. good idea?
Thanks, and have a nice newyears eve!
Eric
fdx.tx(nema.rx)
I like the variable resistor approach, just be careful not to zero the value (I'm an expert in this field)...
Pins 30 and 31 are used for the connection to the PC. 29 and 28 have the eeprom connected. Use a lower number (any other pin is ok).
So one full duplex serial (fdx) is used to send data to the PC, and uses the hard wired connection to pins 30 and 31. You'll get data back via your USB cable.
After loading the program to RAM launch the terminal (or enable it if already running).
Note that the terminal disables when not active.
Set port and baud rate and you are ready.
You should get data from the prop at this point.
Just to be sure it works you have a delay before fdx.tx(0), as an alternative I wait for a key entry.
I usually add a line like that
fdx.rx
at this point the prop waits a keypress.
You then should be able to see the welcome string and be sure the serial connection to the PC is working.
Massimo
Thanks again Massimo, you're a hero.
I changed the NMEA input to pin 7; set nema.start(7,26,1,4800) Tried different settings with different results.
When the wind-unit is off I get a black screen in Propterminal.
After startup of the Tacktick wind I see the red light at the USB blink about every second: signal! The Propterminal produces strange unreadable symbols, every second a fresh black screen with a new line:
changing baudrate (9600) or mode, the symbols change, but never make any sense... :-(
mode 0 or 2 also results in full screens with sentences in between:
Btw: never saw the string ("Just a start message",13) What does the 13 mean?
Similar results with Serial Mirror NMEA.
How can I get some sense in it now? Tried searchin the forum, but can't think of a suitable term...
Eric
Can't help with the rest of the neat stuff going on, but a 13 is ASCII for CR, (Carriage Return), for an end of line.
Getting closer..
the full duplex serial object has this config comments:
So your interesting mode bit is the one driving the receiving part.
You can set mode to 0 or 1. If the mode is right you only get bursts of data, and noting in the middle.
If the mode is wrong you get a lot of useless data because the the idle level is mistakenly interpreted as data (in fact the repeating symbol you get is corresponding to decimal value 128 - binary 1000_0000, if you check the propeller char table).
Garbage bursts mean wrong baud rate.... i searched the internet for a value but with no success. Try to use other values, even higher, maybe...
Remember also to set the correct baud rate on the prop terminal, otherwise the garbage is terminal side. If you run Cluso's example it is set to 115200.
If you start the terminal fast enough you should see the "welcome" string.. just to verify the terminal works, and the settings are right...
increase the waitcnt value (10 in place of 5? this is a seconds delay), and add another waitcnt after the welcome string to have time to see it..
Massimo
Realising that the USB-Baudrate was wrong because I never saw the wellcome sentence, I played around with it enlessly and suddenly struck gold: 110000!
Then step by step (1000's first, then hundreds) and found the Tacktick needs between 4500 and 4700 baud :-)
Settled for 4700, as high as possible....
Strangely, only the very first sentence has the famous $-sign, then sentences are headed with II.
A larger screen for PropTerminal would be convenient....
Then, I started up the anemometer, and yes it works!!
So far I can recognise 3 lines:
IIGLL,5217.991,N,00515.945,E,210437,A,A*5A
Geographic position, latitude / longitude
IIMWV,081,R,05.1,N,A*1E
Windspeed and angle,081degree,R?,5.1kt,N?,A*1E
IIRMC,204415,A,5217986,N00515.942,E,00.0,327,,00,E,A*0.4
&RMC, timestamp, Active,Location, North,Location,East,0.00 speed,trackangle degrees true,date?
This contains all the data I need: time, speed, windspeed, and -angle :-)
Next challenge: how to filter and store the data...
Eric
Strange that you need odd baud rate values...
By the way do you have the latest prop tools (1.3)?
In that case installed with it you'll find a parallax serial terminal. This is a better looking terminal, with only standard rate values..
You can change the terminal rate changing the baud constant (now 115200), you can try with 57600.
Tacktick side at this point it should be 4800...
You are supposed to get $all the time.
I'll dig for the MWV sentence...
Massimo
Your baud (rate) seems to be off as if your xtal is incorrect. The serial USB I set to 115,200 baud which is a standard, as is 4800. I would be very surprised if the tactick was off-standard.
I will have a look again, and check 57600
Searching the internet I came accross http://gpsd.berlios.de/NMEA.txt
I'ts statet there that II is code for Integrated Instrumentation. So it could still be proper code... Only the missing $...
also, extended explanation of NMEA lines:
IIMWV,081,R,05.1,N,A*1E
Windspeed and angle:
081(degrees),R(elative),5.1, N(autical Miles), A (Valid)*1E(checksum)
IIRMC,204415,A,5217986,N00515.942,E,00.0,327,,00,E,A*0.4
RMC, hhmmss,A(Valid),Latitude,N(orth),Longitude,E(ast),0.00(Speed knots),327(CourseDegreesTrue), (Date),00.0(MagneticVariation),E(ast),A(Autonomous),*0.4(Checksum)Eric
what is the resistance you are using now?
Massimo
Massimo.
Another mystery solved: the new Terminal shows lines including the $, and with II:
$IIMWV,003,R,00.0,N,A*10
$IIVWR,003,R,00.0,N,,,,*62
Great! you can copy and paste directly from the Terminal! At the same time the "old" terminal shows the lines without $
Changing the baudrate back to 115200 gives me garbage again.....
57600 with 4800 garbage again..
I think I'll stick to my 110000/4700
Could that be caused by the variable resistance? I measured the resistance at 40K.
I'm looking at Google Earth Logger, to learn how data can be extracted and saved.
I guess it's time to order the SD-card holder... And the VGA-connector kit.
Suggestions are allways welcome :-)
Eric