I can select the 100 ms, but it shows the Navigation Rate 1 cycle red, maybe its my old version of U-Center. Once I select 200 ms the red background disappears. I read on the web that Glonass cannot take the 10 hz, maybe old info

have you tried, gps, galileo and bideu.

No.
Is there a good reason to try that?

well if glonass doesn't work it would be interesting to see if biedeu does.

I did a very brief comparison and there doesn't seem to be a lot of difference in Australian sky coverage, so I've gone with glonass

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tbwonder said..


I am using 10hz and 19200 transfer rate to the logger.

I tried setting the log rate to 19200 but the files get corrupted and cannot be processed. Tried both on the water and a static test on the balcony. When I revert to 9600 all good.
My config is same as you now:
GPS, Galileo and Glonass, UBX PVT, 10 hz.
And also the parts I am using are the same, did you have to do anything else to set the baud rate?

I remember it being a little tricky to set the baud rate on the BN880 in U centre, as you are connected to the port that you are changing the setting on. It took me 3 or 4 goes to get it to change to 19200. Then of course you need to change the baud rate on the logger to match. But that is easy with the config file.

Yep also took me a while, change the gps rate in "rates" then change the U-center baud rate to match.
I'm not sure how critical baud rate is. But when we started this the feeling was the default 9600 would be too slow.
I ended up with 115200 and Manfred appears to be using 38400 for a 25hz unit. So I could probably drop mine back quite a lot.

I am so stupid ! I forgot the open logger config... all good now.
tomorrow test at 10hz, 19200 baud, wroooom , thanks !!!

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decrepit said..
Yep also took me a while, change the gps rate in "rates" then change the U-center baud rate to match.
I'm not sure how critical baud rate is. But when we started this the feeling was the default 9600 would be too slow.
I ended up with 115200 and Manfred appears to be using 38400 for a 25hz unit. So I could probably drop mine back quite a lot.

The ubx navpvt message is exactly 100 bytes (older version 92 bytes). At 10 Hz, you have then 1000 bytes/second. At 9600 baud, the limit is 960 bytes, as each byte needs 10 bits (1 startbit, 8 bits, 1 stopbit). So you definitely need a baudrate at least from 10 kbaud ! As the next standard value is 19200 baud, I use this setting. When you go much higher, you can get into trouble with the interrupt load of your ?-processor. It depends also from the buffer size of the uart. For my diy logger (ESP32 ?), I use the 19200 baud. Works like a charm !

Thanks, I'll slip mine back to 19200 then.

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powersloshin said..
>>> all good now.
tomorrow test at 10hz, 19200 baud, wroooom , thanks !!!

So here's the results, doesn't get a lot better than that, left hand results motion, right hand George's with slightly better sAcc numbers and more sats, 18 for motion 24 for George.

Many thanks to all for spending time to help me on this project.
It took me a while because I was totally ignorant, but to put it together is fairly simple. An issue I had a couple of times is that the log was truncated after only a few minutes, even if I saw the lights flashing at the end of the session: need to investigate, I suspect some dodgy connection.
Another issue is the size of the logs: ubx is about twice as big as motion files, I think this might put a constraint on using even higher rates with M9 chips, Daffy was talking of something at over 20Hz !

I just had a look at th results from Georges test as well. Outstanding!
I agree with Mike. I have not seen any better correlation between Mini Motions. It's right up there. Well done!

yes, I tested a Prototype M9 25Hz gps today at Budgie, and it came out very well in comparison with the Motions, but since I had to wear it on my arm, it was not as well correlated as yours.
File size was
Motion oao = 5.7mb
Prototype UBX = 13.5mb
UBX converted to SBP so I could get it to process in Speed-reader, 4.3mb. (That was a surprise!)
The prototype ubx processed in GPS-Results but not in other programs before converting to sbp.
Processing time was not significantly longer with the 25Hz file and I don't think the size is really an issue with modern storage abundance.

it's too much fun, next will work on the epaper display, I need big fonts to see without glasses. If I only want to see max 2sec, tot distance and time of the day it is very simple to program. If I get some results will talk to TBWonder to port some of his best Garmin features.

Great to have another enthusiast on board! Good luck. I can't help with that, but boardsurfer probably can.

Thanks for this thread! I was looking for GPS logger, but couldn't find anything that I like, or could order, so thanks yo this thread I was able to built one myself, and even print a box for it. Can not post a picture due to the site's policy.

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shor said..
Thanks for this thread! I was looking for GPS logger, but couldn't find anything that I like, or could order, so thanks yo this thread I was able to built one myself, and even print a box for it. Can not post a picture due to the site's policy.

If you were looking for a GPS Logger for windsurfing, what was the reason you did not like the Motion or Mini Motion for your use?

If you were looking for a GPS logger for other uses, there are literally scores of those available off the shelf. What is it you specifically needed that you could not find?

Were you able to print a waterproof box for your build? There is another thread in this forum describing difficulties experienced by others with this. Did you find a solution?

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sailquik said..

If you were looking for a GPS Logger for windsurfing, what was the reason you did not like the Motion or Mini Motion for your use?

If you were looking for a GPS logger for other uses, there are literally scores of those available off the shelf. What is it you specifically needed that you could not find?

Were you able to print a waterproof box for your build? There is another thread in this forum describing difficulties experienced by others with this. Did you find a solution?

I was looking for windsurfing only. Motion/Motion mini is great with one exception - you can not get one. I made an order online on motion's site some time ago but didn't get any response and after checking all the related threads on this forum I got a feeling that the earliest you can get one is sometimes nobody knows when, but definitely not this year. GW-60 is another option that I was considering, but there are way too many threads about various issues with it and I had to rule it out too.

Waterproofing a printed part is a very interesting topic. I use a plug with an o-ring and it seems works. Don't know how good it works exactly - the deepest water I can test with is a bucket - no issues there.

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shor said..
I was looking for windsurfing only. Motion/Motion mini is great with one exception - you can not get one. I made an order online on motion's site some time ago but didn't get any response and after checking all the related threads on this forum I got a feeling that the earliest you can get one is sometimes nobody knows when, but definitely not this year. GW-60 is another option that I was considering, but there are way too many threads about various issues with it and I had to rule it out too.

Waterproofing a printed part is a very interesting topic. I use a plug with an o-ring and it seems works. Don't know how good it works exactly - the deepest water I can test with is a bucket - no issues there.

Yes, for an accurate, reliable windsurfing device, the options are far more limited.
The LCD screen Motion has quite a long waiting list for new orders as Julien is still trying to catch up with over a year of backlog orders amid serious parts shortages, but the Mini Motion (a pure logger, with no screen) has a much shorter wait of only a few weeks. But anyhow, it looks like you have done a very neat job of the build and it will almost certainly work very well.

Please keep us updated with your testing.

Edit: Shor sent me a pic of his build and asked me to share it :

Shor, for sure I am super interested if you can get long term water proof 3D print housing. Like you I can print something that seems to be water resistant and can pass the bucket test for 24hrs no problem. I printed around 20 cases trying to achieve 'water proof'. Take it into the real world for a few days of rain and submersion and there is condensation showing inside the case and pretty soon after that the electronics start doing weird stuff. Its not big time leaking but for sure moisture is getting in. (you can also take this moisture out via sitting in a bag of rice etc). If you do manage to pull it off, many will be interested to know the basics like material, layer height, # perimeters, seam position, over extrusion/over temp amount, any post processing like annealing or other tricks etc. Maybe your way of having a removable lid to then allow the insides to dry after each session is the best approach.

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Flex2 said..
Shor, for sure I am super interested if you can get long term water proof 3D print housing. Like you I can print something that seems to be water resistant and can pass the bucket test for 24hrs no problem. I printed around 20 cases trying to achieve 'water proof'. Take it into the real world for a few days of rain and submersion and there is condensation showing inside the case and pretty soon after that the electronics start doing weird stuff. Its not big time leaking but for sure moisture is getting in. (you can also take this moisture out via sitting in a bag of rice etc). If you do manage to pull it off, many will be interested to know the basics like material, layer height, # perimeters, seam position, over extrusion/over temp amount, any post processing like annealing or other tricks etc. Maybe your way of having a removable lid to then allow the insides to dry after each session is the best approach.

Flex2, thanks for sharing your experience. You know much more on the topic than I do, I'm not even close to 20 cases, printed about 5 so far. I've never thought about long term water proof test to be honest as it is not real life scenario in my case - in order to turn device on/off and get the card I have to remove it from the housing. I could probably submerge a housing to some deeper than a bucket water for a couple of hours while on the water and check it after, but it sounds like that would not qualify as long term. I doubt that it's possible to achieve real water/air tightness with a 3D printed object without some post processing. Covering with a thin layer of epoxy or some varnish should improve water/air tightness for a short period of time, but in the long term I think it will fail eventually. Annealing sounds promising, but I don't have any experience with that either. If I would try to build a custom case that last, I would probably try to make a silicon mold from a printed prototype and try some resin casting. But that sounds like a lot of time and efforts, so 3D printed case with some level of waterproofness is the best compromise that works fine for my use case.

Anyone with a resin printer?

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Flex2 said..
Shor, for sure I am super interested if you can get long term water proof 3D print housing. Like you I can print something that seems to be water resistant and can pass the bucket test for 24hrs no problem. I printed around 20 cases trying to achieve 'water proof'. Take it into the real world for a few days of rain and submersion and there is condensation showing inside the case and pretty soon after that the electronics start doing weird stuff. Its not big time leaking but for sure moisture is getting in. (you can also take this moisture out via sitting in a bag of rice etc). If you do manage to pull it off, many will be interested to know the basics like material, layer height, # perimeters, seam position, over extrusion/over temp amount, any post processing like annealing or other tricks etc. Maybe your way of having a removable lid to then allow the insides to dry after each session is the best approach.

I'd try to give the "painting" the inside and/or outside of the housing with epoxy a shot. Something like West Marine's G/flex epoxy that is specifically made for water proofing applications might work (I'd take the name as a further hint ).

If the problem is just a bit of condensation, and the case can be opened easily, try the anti-fog inserts for GoPro. They work quite well and are reusable after drying them in a oven. The GoPro dive housings are generally fully water proof, but every now and then, a bit of sand on the sail can make water creep in, and inserts are quite wet after a session, but the footage is still great.

I've also had some success with silicon coating to waterproof "IPX7" bluetooth headphones which have visible holes. I followed the instructions at www.instructables.com/How-to-Waterproof-Electronics/ to coat the electronics on the inside, and the head phones survived crashes that would have killed them without the coating. Quick and easy, and may prevent some of the "weird stuff" from happening.

boardsurfr, I checked out that 'flex' epoxy...ain't cheap. Whilst I'm sure a coating of some sort inside and out will help a great deal with water proofing, my guess, like Shor's feeling is the outer coating will wear over time in places and moisture will seep into the plastic and you'd be left with just a tiny inside coating doing the protection. I was trying to make a case that never opens, to minimise complexity and potential seal failures (as Jan's DIY GPS design on other thread is suited to a fully sealed case with wireless charging and data xfer). Will try a few more attempts at printing with coating but thinking at present machining a case out of solid plastic and sealing with a positive pressure inside is going to give a better result. Since there is no wind for a while might get round to it.

Shor, I'm no expert to be sure. I agree annealing might be a way forward but it distorts/shrinks the print which means lots (more) trial and error and harder for others to copy. Resin printer might be an option too...just more and more toys...

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Flex2 said..
I was trying to make a case that never opens, to minimise complexity and potential seal failures

In that case - why not just laminate the whole thing? Fast, cheap, waterproof, and even can be opened a bit more easily than the Motion cases. A single layer of light cloth may be transparent enough, or if not, just do the edges of the top, and leave the center free.

boardsurfr, I guess by laminating you mean a fibreglass inlay (or outer) shell. Whilst cheap it is another step (better to just make a mould and cast it?) and as per my recent post on Jan's thread, something else go'n on

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Flex2 said..
boardsurfr, I guess by laminating you mean a fibreglass inlay (or outer) shell. Whilst cheap it is another step (better to just make a mould and cast it?) and as per my recent post on Jan's thread, something else go'n on

Sure, it's another step, but takes about as long as writing a couple of posts here, and many windsurfers have the materials around. Plus it's known to be quite waterproof.