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-   -   Sub $50 10Hz GPS Receiver (https://www.miataturbo.net/race-prep-75/sub-%2450-10hz-gps-receiver-82941/)

NiklasFalk 02-05-2015 03:59 AM

Not to be a dick, and it's a little more than $50, but have been available for ages (Qstarz BT-Q818XT). But that includes a more cave-man-proof concept.
The sensitivity of the antenna and more importantly the processing of the data will give different results when it comes to positioning and mounting.
I never had a problem with a Qstarz unit duck-taped to the cage (even on the A-pillar tube, with the A-pillar and the glass in the way), when using Racechrono. The frequency makes the positioning on track good enough (it's always better when you have some extra satellites and crisper data of course).

That RT DL1 have problems when there is any minor flaw in the data falls in their way of working, fix the sensors, and let the unit/software show the sensor data as-is (even create some smoke when the input voltage is off). Filtering and protection is for sissies.

Braineack 02-05-2015 08:12 AM

Was hoping for a $50 10Hz subwoofer...

aidandj 02-12-2015 11:54 AM

1 Attachment(s)
Got a couple of these in the mail today. Need to do some testing to see how much power it will consume.

http://i57.tinypic.com/etwoap.jpg

Case will be designed similar to this.

https://www.miataturbo.net/attachmen...ine=1423760093

aidandj 02-14-2015 06:52 PM

Got my second chip in the mail today. I like this one better. Cheaper, larger antenna, simpler connections.

I took it outside to get a fix and once it had it I was able to go back in my house and keep the fix. I need to take it for a drive still but good so far.

http://i61.tinypic.com/33y029d.jpg

aidandj 02-17-2015 05:40 PM

Updates, got everything connected, currently designing a case. Testing will happen today or tomorrow:

http://i58.tinypic.com/10e0e9v.jpg

http://i58.tinypic.com/97jsiq.jpg

http://i58.tinypic.com/j7fgix.jpg

EO2K 02-17-2015 05:45 PM

I am excite!

aidandj 02-17-2015 06:07 PM


Originally Posted by NiklasFalk (Post 1203147)
Not to be a dick, and it's a little more than $50, but have been available for ages (Qstarz BT-Q818XT). But that includes a more cave-man-proof concept.
The sensitivity of the antenna and more importantly the processing of the data will give different results when it comes to positioning and mounting.
I never had a problem with a Qstarz unit duck-taped to the cage (even on the A-pillar tube, with the A-pillar and the glass in the way), when using Racechrono. The frequency makes the positioning on track good enough (it's always better when you have some extra satellites and crisper data of course).

That RT DL1 have problems when there is any minor flaw in the data falls in their way of working, fix the sensors, and let the unit/software show the sensor data as-is (even create some smoke when the input voltage is off). Filtering and protection is for sissies.

I've seen that one. But cost of materials right now is 25 dollars. Which is almost a 4th of the cost of the Qstarz one.

midpack 02-17-2015 06:53 PM

I so want one of these. A comparison between RaceChrono with built-in GPS (Galaxy Nexus) vs transponder at Hallett showed times anywhere from dead accurate to somewhere around a second off. Not exactly a reliable means of measurement. These times are from my 3rd, and final, session of Friday at Miatas@Hallett. That last lap was the death of my poor little IHI.

Code:

RaceChrono        Transponder
1:50.24                1:51.585
1:36.38                1:36.337
1:31.50                1:31.509
5:27.44                5:26.538
1:34.61                1:35.544
1:31.61                1:31.610
1:31.51                1:31.476
1:30.58                1:30.617
1:33.23                1:33.263
1:31.94                1:31.913
1:32.68                1:32.642
1:31.04                1:30.848
1:33.98                1:34.171
1:29.97                1:29.968


Leafy 02-17-2015 06:56 PM


Originally Posted by midpack (Post 1207030)
I so want one of these. A comparison between RaceChrono with built-in GPS (Galaxy Nexus) vs transponder at Hallett showed times anywhere from dead accurate to somewhere around a second off. Not exactly a reliable means of measurement. These times are from my 3rd, and final, session of Friday at Miatas@Hallett. That last lap was the death of my poor little IHI.

Code:

RaceChrono        Transponder
1:50.24                1:51.585
1:36.38                1:36.337
1:31.50                1:31.509
5:27.44                5:26.538
1:34.61                1:35.544
1:31.61                1:31.610
1:31.51                1:31.476
1:30.58                1:30.617
1:33.23                1:33.263
1:31.94                1:31.913
1:32.68                1:32.642
1:31.04                1:30.848
1:33.98                1:34.171
1:29.97                1:29.968


Sounds about right, the gps on your phone only polls once per second (1Hz).

aidandj 02-17-2015 09:37 PM

1 Attachment(s)
Case printed and cut:

Attachment 234392

creon 02-18-2015 03:40 PM

I zee
1 bluethoot module
1 GPS module
1 mini USB for power suply

Is that all?
No extra arduino to translate the GPS code because the output trok GPS is what Android neer
Only set the baut and code of the bluethoot module and your good to go?

aidandj 02-18-2015 11:12 PM

So the chip that Schuyler linked doesn't have flash memory so the 10hz setting doesn't stick. Because of this I switched to a different chip that has flash, but that won't be here for another couple weeks.

Schuyler 02-19-2015 02:48 AM


Originally Posted by aidandj (Post 1207470)
So the chip that Schuyler linked doesn't have flash memory so the 10hz setting doesn't stick. Because of this I switched to a different chip that has flash, but that won't be here for another couple weeks.

D: I already ordered it. #YOLO. It gets an atmeta chip to program it errytime I guess.

EDIT: it's 3am and i'm cramming for a test, but I went and got a double 1/4 pounder with cheese and I think something of that magnitude deserves a break. Look through the manual at the Electrical Programmable Fuse (eFUSE). My understanding is you set it up the way you want it, send the binary code, and it burns the current settings to the chip. One time use, hence the "fuse" part. Worth looking in to. http://www.reyax.com/Module/GPS/RYN25AI/RYN25AI.pdf

aidandj 02-19-2015 09:11 AM

Already did. eFuse is cant set the refresh rate, only the baud rate. I even confirmed with the manufacturer.

aidandj 02-19-2015 09:20 AM

Good luck in your test. The flash chip is only 18 dollars btw.

Full_Tilt_Boogie 02-19-2015 10:20 AM


Originally Posted by creon (Post 1207330)
I zee
1 bluethoot module
1 GPS module
1 mini USB for power suply

Is that all?
No extra arduino to translate the GPS code because the output trok GPS is what Android neer
Only set the baut and code of the bluethoot module and your good to go?

These GPS modules output serial (as well as i2c), so you dont need anything else. Youre just transmitting serial over bluetooth.

creon 02-19-2015 10:33 AM

this tread now becomes more intresting
thanks for the reply Tom

aidandj 02-19-2015 11:04 AM

Just got off the phone with ublox, and there is definitely no way to set navigation rate in eFuse. Oh well.

Schuyler 02-19-2015 11:28 AM

Meh I'll cost me $2 to add an ATMEGA328 chip to it, just more work. I think I have 4-5 them somewhere, so I'll probably just do that since I already have the chip. Props (but I'm mobile and don't know how) for digging in to that though, good to know.

aidandj 02-19-2015 11:30 AM

I have the command for changing the rate somewhere written down too, but its pretty simple. I'm buying the flash chip just for science. Funny how this has cost me more than the Qstarz module.


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