Rocket Track - Open Source GPS Tracker for Smartphones

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I got the LCD Rx working! Can't beat it for only $50 dollars, now I just have to put it inside the enclosure. BTW if anyone is wanting to buy a Xbee USB explorer from Sparkfun. Type in code FALL2014 and you should get $10off.

 
that is pretty cool! very clever using the xbee explorer for the rx.

well done!
 
Derek, I've seen some short (<12") RP-SMA cables that serve to separate the actual antenna from the jack on the transmitter. Fatalist that I am, I could foresee a situation (and have seen some comments out in cyberspace) about jarring forces on the antenna cracking the circuit board on the XBee. I was thinking that, placing the antenna in the nose cone with a 'loop cable' between it and the actual XBee (looped 360deg and then connected to the XBee) would allow for *some* separation (and shock absorbency) from the two components if, perchance, the vehicle came in hard (probably nothing would save it if it came in ballistic - but, if a canopy fouled and it (again) came in 'hard') and having that 'loop cable' would (maybe) save the XBee.

Just curious what kind of performance 'hit' inserting that cable assy would be (i.e. transmission range attenuation, etc.).

-- john.
 
Just curious what kind of performance 'hit' inserting that cable assy would be (i.e. transmission range attenuation, etc.).
A properly-designed extension cable should have minimal loss. That said I use wire antennas on the flight side because they're lighter and more robust and I haven't had any range issues.

Also, if you put the tracker in bubble wrap it will survive a crash much better.
 
Is there a current parts list? Ive been trying to follow along but got lost with all the upgrades and versions. About what price is the total for the whole package?
 
ok so the only thing I need to do to the XBEE modules is change the baud rate to 115200 correct?
 
Derek, I've seen some short (<12") RP-SMA cables that serve to separate the actual antenna from the jack on the transmitter. Fatalist that I am, I could foresee a situation (and have seen some comments out in cyberspace) about jarring forces on the antenna cracking the circuit board on the XBee. I was thinking that, placing the antenna in the nose cone with a 'loop cable' between it and the actual XBee (looped 360deg and then connected to the XBee) would allow for *some* separation (and shock absorbency) from the two components if, perchance, the vehicle came in hard (probably nothing would save it if it came in ballistic - but, if a canopy fouled and it (again) came in 'hard') and having that 'loop cable' would (maybe) save the XBee.

Just curious what kind of performance 'hit' inserting that cable assy would be (i.e. transmission range attenuation, etc.).

-- john.

the rule of thumb we use at work is .5 db per connector. The cable loss should be pretty close to 0 if it is decent.

but Mike offers the best solution: use the wire antenna version of the xbee if you are worried about the rp-sma connector getting damaged.
 
Is there a current parts list? Ive been trying to follow along but got lost with all the upgrades and versions. About what price is the total for the whole package?

all of the parts lists are in post 5. iirc, the tx costs about $80 and the rx costs about $110. so figure about $200 with antennas, batteries, shipping etc.
 
the rule of thumb we use at work is .5 db per connector. The cable loss should be pretty close to 0 if it is decent.

but Mike offers the best solution: use the wire antenna version of the xbee if you are worried about the rp-sma connector getting damaged.

A bulkhead mount antenna connector either projecting into the main parachute bay or out the aft end for apogee deployment/exposure would be a good idea to save the circuit board from breaking the connector. An SMA antenna is easy to replace. A broken board is likely to brick the transmitter.

Alternatively, a wire antenna going through a form fitting hole in a bulkhead sealed with clay or putty and stented with a cardboard tube with duct tape wrapped around it to protect against the momentary flash of the deployment charge, is very workable. I use the cardboard tubes the Aerotech wire motor igniters come in for stenting purposes in a Wildman Jr. The "stent" protects the wire against getting squished by the parachute in the main bay.
Make sure you do not use metallic paint on the rocket as it can shield the Rf from getting out. At least that happens at the 70cm band (420-450Mhz)

The procedure is slide the antenna through the bulkhead, apply some clay or chaulk on the surface for a seal. Slide the tube over this and more clay at the base of the cardboard stent to support the wire in the middle. I usually can get my last packet between 50 to 100' above ground level at a couple of miles out with a BeelineGPS (only updates ~5 seconds). With these other trackers that update ~1/second the last received packet might come at an even lower AGL. With the 900Mhz trackers look up a patch antenna to extend the received range more if necessary. Kurt
 
Ok thanks! One more question, how do you know when the gps is locked? As if know the only LEDs that turn on are the green and lower red.
 
Ok thanks! One more question, how do you know when the gps is locked? As if know the only LEDs that turn on are the green and lower red.

What I do before I leave for a launch is turn on whatever GPS tracker I'm using and let it acquire the satellites. Has sometimes taken 10 minutes if the tracker hasn't been used for weeks to months. Have to watch the receiver for incoming packets.

When prepping a rocket I turn the GPS tracker on first thing so it has plenty of time to get a fix.

Now, for an Android based receiving system (EggFinder type) there is a Bluetooth GPS utility that is very useful go confirm lock. It's called "Bluetooth GPS":
https://play.google.com/store/apps/details?id=googoo.android.btgps&hl=en

One can call up this app and use the incoming packets from the tracker via the Rf link and confirm how many satellites are being used in realtime! It can temporarily subvert the "internal" GPS of the Android device. When satisfied. can unpair the program from this link and use GPS rocket locator to track.
For an Apple based OS I don't know of any realtime tracking solution as I don't use that type of device. Kurt
 
Ok thanks! One more question, how do you know when the gps is locked? As if know the only LEDs that turn on are the green and lower red.

the rocket track app will tell you there is a lock.

also, the mini tx has a lock led.
 
the rocket track app will tell you there is a lock.

also, the mini tx has a lock led.

Ok thanks. I'm using a laptop with a Xbee adapter for the RX because I only have apple devices. I take it the lock LED us the red on the top left?
 
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Ok thanks. I'm using a laptop with a Xbee adapter for the RX because I only have apple devices. I take it the lock LED us the red on the top left?

ok. in that case you would need to look at the data to determine if you have a lock. It should be pretty obvious because if you don't have a lock, then you get $gpgga strings with lots of commas with no data between them.

on the mini tx, the lock led is the one by itself near the battery connection.
 
ok. in that case you would need to look at the data to determine if you have a lock. It should be pretty obvious because if you don't have a lock, then you get $gpgga strings with lots of commas with no data between them.

on the mini tx, the lock led is the one by itself near the battery connection.

ok got it. How can I view the data. I tried opening it up in Putty and got nothing.
 
if you changed the rx xbee baud rate to 115200, then use that. otherwise try 9600 and make sure you use no flow control.
 
if you changed the rx xbee baud rate to 115200, then use that. otherwise try 9600 and make sure you use no flow control.

Ok should the data just start showing up on the page? Sorry about all the questions.
 
Ok got it working. The flow control was on so nothing was coming in.
 
yeah!

I'm not sure how much run time you will get from 2 aa batteries. 3 would be safer.
 
Yes it will be run on a lipo. This was just for testing as I don't have any 1s looks available right now.
 
Does anyone know of any good GPS data converters that I can use on the field to convert my gps data I get off of putty into the gps coordinates? Ive found a few but cannot use them unless I have Wifi.
 
did you try using the fastrax or ublox gps apps? you should only need an internet connection to use the map portion of those.
 
Lessons learned from the field.

So you don't have to learn the hard way (or maybe you already have)

I had a perfect launch and data lock this past weekend, 3-21.15. (I pushed my luck at 7,326 feet, the highest to date for me with the tracker)
While I was waiting for the range to be closed to go get my rocket, I lost connection to the receiver via Bluetooth (I think it was a text message or other "phone" service that did it)
when you lose connection to the receiver, you also lose ALL data! (yes I screamed by bloody head off! I had no idea were the rocket was! No one at the launch had a visual on it either! I assumed it was GONE!)
I knew that when the rocket is on the ground, you have to be a LOT closer to get the signal back, I was NOT happy!

This is what I learned over the next few hours. Hope it helps someone.

First and most important.
The "Map" screen for RocketTrack has a "follow me" feature. This is your best friend (took me awhile to figure out though)
If you've "lost" all the data collected during flight, hit the "follow me" feature. Turned ON, it locks on to your location. Turn it OFF, the map "returns" the last known location of the transmitter (zoomed in). Then just Zoom out and IF you have a satellite view, head towards the direction of the last known location until you get a NEW lock on the rocket. (Love this feature! Would have save me from my heart attack had I known this ahead of time. Hello! The $ in electronics aboard did not make my wife happy as she keep asking "Do you know where it is? I wisely just kept my mouth shut.)

Everything else that would make life much easier, if you're using this on a phone like I am.
Turn your phone in "Airplane mode" before the launch. Keeping the Bluetooth active during flight and until the rocket is found is critical! I know for sure that a phone call disconnects the Bluetooth.
Turn OFF or set the "screen timeout" to the highest setting. (last thing you want to be worrying about is the screen locking, which I found out also might cause the Bluetooth to disconnect! ugh)
Last, but definitely not the least, as soon as the map or data your watching indicates the rocket is "down", SAVE the data before doing ANYTHING else.
At least then if you DO loose Bluetooth connection, you have a SAVED file that you can use to locate the rocket. (hoping you have data service to translate the saved data!) I use this site:
https://www.gpsvisualizer.com/map_input?form=googleearth
creates a KLM file that you can open in Google Earth.

Anyway, I found my rocket and now I'm ready to push the limits on this tracker to higher heights. Planning on 12K and possibly 18K at hellfire. I'll post my results.

Thanks Derek for sharing your GPS tracker with us!
It allowed me to stay out of the dog house this past weekend! Felt like the last guy in this video! Lived to see another launch day! yay
[video=youtube;_6D6eP6EMj4]https://www.youtube.com/watch?v=_6D6eP6EMj4"]https://www.youtube.com/watch?v=_6D6eP6EMj4[/video]
 
I got the LCD Rx working! Can't beat it for only $50 dollars, now I just have to put it inside the enclosure. BTW if anyone is wanting to buy a Xbee USB explorer from Sparkfun. Type in code FALL2014 and you should get $10off.


How do you do this?
 
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