$25 GPS Solution

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CORZERO

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https://www.aliexpress.com/item/HAK...32799709822.html?spm=a2g0s.8937460.0.0.lWTIuU

100mw 3DR version:

https://www.aliexpress.com/item/3DR.../1440940555.html?spm=a2g0s.8937460.0.0.lWTIuU

500mw 3DR version:

https://www.aliexpress.com/item/1se...32801613368.html?spm=a2g0s.8937460.0.0.qkKkGS

100mw Tx range tested line-of-sight with no issue to one mile with stock antennas. U-center 8 and Visual GPS programs used. Radios programmed with Mission Planner 1.3.46.

https://firmware.us.ardupilot.org/Tools/MissionPlanner/

Tx dimensions without antenna = L33mm x W20mm x H10mm

1S Lipo. 4 wire connection; V, G, Tx, Rx.



20170724_154139.jpg20170724_154329.jpg20170724_154341.jpg20170724_154413.jpg20170724_154420.jpg20170724_233217.jpg20170724_233235.jpg
 
So these are individual pieces you bought, disassembled, and made what you have pictured? Could you make a build thread for it? :)
 
I find the rfdesigns software easier to use to program the radios, and use the ublox ucenter software to display the results on a laptop.
If you link a Bluetooth module to the base unit you can receive the coordinates on an android phone or tablet.
I did a build thread on the Australian forum for a near identical system. https://forum.ausrocketry.com/viewtopic.php?f=32&t=5240
 
So these are individual pieces you bought, disassembled, and made what you have pictured? Could you make a build thread for it? :)

It's pretty simple really. You already described half the build! I used 3M double sided tape to attach the GPS antenna to the back of the radio and clear 1" shrink tubing over the assembly. I removed the wiring from the GPS antenna to install my own connections. The radio plug is JST-SH. I wired power with a JST plug for the radio and the GPS antenna together.

https://www.ebay.com/itm/20-sets-Mi...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

https://www.ebay.com/itm/2-FEET-1-0...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649
 
What's the difference between the op and nz gps units ?
 
What's the difference between the op and nz gps units ?

The plugs that come with them, which you don't need if you wire it like I did. The GPS boards are the same. The JST-SH plug is required for the 3DR, so either OP or NZ type connections won't work anyway. 3DR radios usually come with a couple of JST-SH plugs so you don't need to purchase anything extra to get hooked up and running. If you screw up and need more plugs however, see the above ebay link :)
 
A couple of things. 1. Can more than one be flown at once? Heck if the encoding protocol for the telemetry signal doesn't allow that, no utility there. Me thinks it's designed so many can be operating at once.
2. 433Mhz would be more efficient as far as propagating but technically only a licensed Ham could use. A callsign needs to be transmitted every 10 minutes. Actually one could take their H/T and announce on frequency they're
transmitting data and I bet that would be with in the law. (Once every ten minutes of course). Another thing, it's likely the NMEA stream can be piped to any tracking program to be used for plotting. Me thinks I'll order a set
and try it out on 433Mhz. Kurt KC9LDH
 
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Thanks for sharing this!

I ordered it in 433mhz figured I have my tech license might as well use it . I ordered 1 100mw and 1 500mw
 
Cool, is the 433Mhz version frequency agile or will everyone be on the same freq?
 
Be careful with the higher power units. As your Tx power goes up so does the chance of internal EMC (electromagnetic compatibility) problems. With more power you have to be more careful that RF doesn't get into the other electronics and mess things up.

I had a GPS system a few years back that set off my deployment charges on my MAD-based ejection system when sitting on the pad. That was a 477MHz based 100mW system IIRC. Ground testing is a must, with all systems running.
 
Cool, is the 433Mhz version frequency agile or will everyone be on the same freq?

3DR radios can be programmed to whatever frequency you want within the frequency range. I use Mission Planner to set radio frequencies, our friend from down under uses rfdesigns, which I have also used and the UIs are basically the same for each. I use 914.65mhz for the 915 radio and 433.90 for the 433 radio. So theoretically you could have a field full of fliers using 915 radios and no duplicate frequencies stepping on each other.

Edit: Perhaps that was the wrong answer for you. The frequency range for 433 is 433.05 to 434.79 with a center frequency of 433.92. You can program the radios to any frequency in that range.

Edit edit: Nevermind me, didn't realize who you were until after I wrote this response. Apparently I was singing to the choir. Is there something I'm missing about your question?
 
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Be careful with the higher power units. As your Tx power goes up so does the chance of internal EMC (electromagnetic compatibility) problems. With more power you have to be more careful that RF doesn't get into the other electronics and mess things up.

I had a GPS system a few years back that set off my deployment charges on my MAD-based ejection system when sitting on the pad. That was a 477MHz based 100mW system IIRC. Ground testing is a must, with all systems running.

Ground test, I concur. I probably have ten fold the time into ground testing as I do actual flying because, well, I really only have access to significant airspace once a month during club launches :)

I am not certain however, how sensitive other made for rocketry/rocketry-specific electronics are to EMI. I haven't had any problems and if I did I would not use those electronic components that were that poorly built and sensitive. Quads are packed FULL of electronics just like any other RC craft with a relatively low incidence of EMI related failure.
 
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Thanks for sharing this!

I ordered it in 433mhz figured I have my tech license might as well use it . I ordered 1 100mw and 1 500mw

It's an easy build. On the GPS board is V, G, Rx, and Tx indicated. Splice radio and GPS board voltages and grounds to your preferred plug and you're set. Just remember to connect radio Rx to GPS Tx and radio Tx to GPS Rx!
 
I am not certain however, how sensitive other rocketry electronics are to EMI.
If the circuit has been designed with RF immunity in mind then you will be less likely to have problems. Shorter wiring on the assembled system helps too. Field strengths can get reasonably high in confined quarters sometimes.
 
I'm running the latest build of Android so hopefully that works. Is there an app out there or would I have to program my own (possible but very time consuming for me).
 
I'm running the latest build of Android so hopefully that works. Is there an app out there or would I have to program my own (possible but very time consuming for me).

That seems to be the $64,000 dollar question!

So far (in my research) the only option for compatibility with android is through bluetooth. There are several excellent apps available, including my favorite, "Bluetooth GPS".

As for Android and USB OTG, I have yet to find a program that works. USB OTG is a popular method for Android 3DR telemetry in the drone world using GCS program (ground control station) but I haven't been able to get any of the programs to work with just the NMEA data coming in and nothing else (say, from an APM or other flight controller board on the air side).

I have had no success with USB terminal apps or NTRIP clients. I'll throw in a free setup if anyone can provide an android USB OTG solution. I don't even care how basic it is. All I want is the NMEA data without wiring up another battery and bluetooth module and lugging it all around.
 
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OK, I just ordered the 100mW @ 433 MHz (I have a tech license), and the GPS module. With free shipping and a $2.00 off coupon, it came to $23.49. First time I have ordered from AliExpress. The rest of the stuff I have on hand at my workbench.

At this point, just experimental use. I may include it on my Level 1 attempt rocket, which has now probably moved to next year. Seems as if the nearest field will be downgraded to G motors or below due to landowner harvesting sod in the previous launch location. The prefectures are now looking for a new field, but it will be next year at the earliest it seems.

I look forward to flight report assessments from this setup.
 
Nice! China has really amped up their shipping procedures and efficiency in recent years and thus is becoming a major competitor/threat to popular brands found domestically (even if made in China). The world is definitely a smaller, more competitive place because of it. I have ordered all kinds of crap from; Banggood.com, AliExpress.com, Gearbest.com, Everbuying.com and various other Shenzhen Valley merchants with ZERO issues and always within (and often within the bottom half of) shipping estimation windows, which have never been more than 3 weeks. Most orders arrive within two weeks, and shipping is usually either negligible or free.

If you can plan for and have a little patience, you have opened yourself up to a new market of inexpensive products. Rather than just Samsung Galaxy or Iphones being your popular cell phone brands, soon you will see about fifty different brands out there which perform just as well and contain the same hardware.
 
Just today, I received a micro tap and die set direct from China. They said it would arrive between August 2nd and August 24th, so I am pretty pleased with that speed.

I ordered a 3D printer kit from Gearbest last October, and got it in 12 days. Recently built an enclosure for it, and I'm hammering out ABS parts right and left. Less than $200 invested in that, but a great many hours of shop time. And they said I would be bored to tears in retirement. They could have not been more wrong. I'm having a blast.
 
Hokay, The 3DR radios are programmable as far as frequency is concerned. Rf messing with deployment electronics is a real though diminishing possibility. Anything by EggTimer has opto-isolation on the deployment side so resistant to Rf interference.
The MARSA is resistant as likely as others are. I've been burned by Rf whacking a P6K, I've seen Adept 22's in a dual installation shutdown by a 2 watt dog tracker and make a rocket go in ballistic and the AIM2 controller specifically states in the
manual it doesn't play well with Rf.

That said, do an all up ground test with contained ematches with all the electronics on and let the rocket sit for 45 minutes to an hour. If the matches don't pop, the deployment devices don't recycle or shut down, you should be good for flight.
Also nose mounting the tracker will help.

500mW at the 70cm band would be good for > 50,000 feet easily depending how good the receive station is.

I ordered a 70cm set and will try to get it going with a small tablet and see if I can get it working with "GPS Rocket Locator" on the Android side. Android is screwy. Plug a dongle in and it will suck the battery life out of your device. Try a Y cable for a Dongle and
you cannot use the Dongle and power the arrangement at the same time. One has to get a program Elemental-X and have a compatible rooted device: https://elementalx.org/
With this utility you can configure it to connect external power AND a dongle (or memory) at the same time so you don't run out of juice. The trade off is the OTG socket will not be able to read or use memory sticks "without" power attached through a Y cable
anymore. That's acceptable because it's not permanent. One can run the program from TWRP recovery and set it back to "stock". Again this is just supported by the devices listed at elementalx.org and one has to "root" their device.

Sooooo...... What this means is it might be possible to plug this dongle into, in my case, my Nexus 7 2013 Flo and Deb tablets and run GPS Rocket Locator on Android with an external battery connected to account for the high "juice" requirements.

I also have a dual boot tablet, Win/Android that has a stock USB 2.0 socket that could directly accept the 3DR receiver and two other inputs for external power. Same holds true if one owns a Winbook as it has standard and MicroUSB (for external power).
On the Windows side, one could do direct GPS mapping with any Ham APRS tracker but only the NMEA/GPS input could be used. Could see where the rocket went but wouldn't be able to navigate. Can lift the positions off into another mapping GPS and go to the last known position. The problem with most APRS Ham tracking programs is they assumed one is going to be receiving APRS packets for tracking and a local NMEA/GPS datastream is the only thing required
to keep track of "one's" position. None of the programs (except YAAC) allows anyone to define a second NMEA/GPS stream to plot. YAAC can be configured to take NMEA strings off another USB receiver and plot them while
keeping track of it's own position.

The GPS program YAAC: https://www.ka2ddo.org/ka2ddo/YAAC.html once one puts Java in their Windows tablet will run. B/T in Windows stinks and doesn't work with YAAC at all but the 3DR USB receiver could work.
I've been able to get a B/T GPS to pair and run with Windows/YAAC so the local position should be ok.

Now YAAC is the only Windows Ham program that can keep track of two NMEA data streams at once and be setup directly. It's pretty easy as the rocket is plotted as a "pseudo" APRS position (one doesn't have to understand that) but it works.
Two other programs APRSISCE32 and the Linux Xastir can do the trick but takes some work to setup. YAAC I can reduce the instructions to a single page.

A non-Ham would legally be able to use YAAC with a 915Mhz tracker as long as they don't connect up Ham equipment or try to transmit via the internet to the APRSIS backbone.

I've messed with this before and got it to work with "wired" devices but gave up on the Windows side as I wished to use B/T peripherals. Since the 3DR is a USB receiver, might be worth looking into again and if it's eas"ier" to setup I will
try to post instructions a "real" person could effectively follow so to be able to track real time with a "map in hand". You experience that once and you'll be hooked.

If there are timing issues between the devices this could fail but what the hey, the software/maps are free and the hardware cost is nominal ( I got all the other stuff on hand) Kurt KC9LDH
 
Alright after reading the wall of text :p I think the easiest approach would be to use Bluetooth to transmit the data to my phone. From there I can write and app that takes the raw data and gives me coordinates that I can then plug into google maps. So I can get the GPS piece but for doing Bluetooth I assume i would need to plug it into a board that sends the data to my phone as it wouldn't know what to do with the data otherwise.

However, the GPS Rocket Locator app looks like it could work if I had a way to convert the raw NMEA into usable data, unless the app does it itself.

If the Rocket Locator app works with the need to convert data then all that's needed is a means to transmit the data over Bluetooth. (I have a 5000mAh battery pack so I will have plenty of juice) I've never programmed an arduino or any other kind of thing so I wouldn't really know how to but I think with how cheap they can be bought it might be worth it to invest. If this works out it would be a nice cheap way to track rockets as I have lots a $100 tracker when the nose cone landed in water and it drowned.

I will look at arduino and see if I can find some stuff for cheap but I doubt I can convince my dad to let me buy anything because I still need an RRC3 to even be able to fly.


EDIT: I have posted on the Arduino forum asking for advice on a board. Here is the thread if you would like to follow as well though I will post results here. https://forum.arduino.cc/index.php?topic=491603.0
 
For Bluetooth, HC-06 on eBay is easy to use with Android and reasonably cheap.
 
Alright after reading the wall of text :p I think the easiest approach would be to use Bluetooth to transmit the data to my phone. From there I can write and app that takes the raw data and gives me coordinates that I can then plug into google maps. So I can get the GPS piece but for doing Bluetooth I assume i would need to plug it into a board that sends the data to my phone as it wouldn't know what to do with the data otherwise.

However, the GPS Rocket Locator app looks like it could work if I had a way to convert the raw NMEA into usable data, unless the app does it itself.

If the Rocket Locator app works with the need to convert data then all that's needed is a means to transmit the data over Bluetooth. (I have a 5000mAh battery pack so I will have plenty of juice) I've never programmed an arduino or any other kind of thing so I wouldn't really know how to but I think with how cheap they can be bought it might be worth it to invest. If this works out it would be a nice cheap way to track rockets as I have lots a $100 tracker when the nose cone landed in water and it drowned.

I will look at arduino and see if I can find some stuff for cheap but I doubt I can convince my dad to let me buy anything because I still need an RRC3 to even be able to fly.


EDIT: I have posted on the Arduino forum asking for advice on a board. Here is the thread if you would like to follow as well though I will post results here. https://forum.arduino.cc/index.php?topic=491603.0

Just use this:

https://play.google.com/store/apps/details?id=googoo.android.btgps&hl=en

The program has everything you need to track. Rocket Locator works with NMEA by default, but you will need a network connection for plotting. I'm not sure why some people are so adamant about having a program plot a course from point A to point B for them. I guess the days of being able to read a map, figure out where you are and plot your own course are lost for some.

The HC-06 module is all you need for a BT connection. Just cut an old USB female cable and wire it up, pair with the application and that's it. But again, the radio and BT module will require power. My goal was to plug the 3DR receiver directly into my phone and not need any additional hardware. The Rx uses nothing for power, so I'm not sure why some are concerned with cell phone battery life. I would wager the apps most people don't know are running in the background suck more juice than an OTG radio receiver.
 
I recently seem to have had a total lapse of cognitive ability and have been staring at my USB to micro USB adapter here:

https://www.aliexpress.com/store/pr...-mobile-phone-to-USB/1988232_32669867029.html

for days with the idea that it was an OTG adapter, which is not, and they are not the same. Micro OTG requires a jumper between pin 4 and pin 5.

I just ordered a hand full of micro OTG adapter cables but in the meantime I will make one for testing purposes from some old cables I have. After I get it built I will re-attempt using a few of the Android applications that I was unsuccessful with previously and hopefully report back with a Bluetooth-less solution.

Edit: Or maybe what I have is an OTG adapter and not just a USB to micro USB adapter. Still researching.
 
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This is a really cool project. I can't profess to understand the details, but from a hardware side it looks like you have a near off-the-shelf setup for low $. You get that android interface working, and I might be on one of these setups. Appreciate your efforts and sharing the project either way...I'll go back to watching from the shadows now.
 
Alright after reading the wall of text :p I think the easiest approach would be to use Bluetooth to transmit the data to my phone. From there I can write and app that takes the raw data and gives me coordinates that I can then plug into google maps. So I can get the GPS piece but for doing Bluetooth I assume i would need to plug it into a board that sends the data to my phone as it wouldn't know what to do with the data otherwise.

However, the GPS Rocket Locator app looks like it could work if I had a way to convert the raw NMEA into usable data, unless the app does it itself.

If the Rocket Locator app works with the need to convert data then all that's needed is a means to transmit the data over Bluetooth. (I have a 5000mAh battery pack so I will have plenty of juice) I've never programmed an arduino or any other kind of thing so I wouldn't really know how to but I think with how cheap they can be bought it might be worth it to invest. If this works out it would be a nice cheap way to track rockets as I have lots a $100 tracker when the nose cone landed in water and it drowned.

I will look at arduino and see if I can find some stuff for cheap but I doubt I can convince my dad to let me buy anything because I still need an RRC3 to even be able to fly.


EDIT: I have posted on the Arduino forum asking for advice on a board. Here is the thread if you would like to follow as well though I will post results here. https://forum.arduino.cc/index.php?topic=491603.0

You need the provided USB Dongle to get the received data into your device be it Windows or Android. Now if you have access to a receiver that can decode the NMEA strings that has a B/T option then you can avail yourself of that. The EggFinder system does just that for ~$125.00 and you have to spend a few bucks for the B/T module for the LCD receiver.

I'm not so sure that the provided receiver has a B/T option. If it does, then one is in business. Personally I am interest in the higher output 433Mhz tracker as it
stands a better chance of sending strings that are easily deciphered at longer range. Yes, of course the battery/power/current requirements go up but if
using a large enough rocket, a larger battery for the tracker is no big deal. Kurt
 
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