Smartphone GPS Tracker Version 1.0

Derek said:

it looks like you have two different modules?

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Sorry, the USB module picture is from the eBay posting. It does not come with a module and you are correct, that module is different from the 2 I purchased as shown in the 1st picture. I have not received the usb module yet. Coming from China, I hope...

Dick

gotcha.

Derek, have you started new thread for V 1.5 or V2.0?

have you had a chance to think about if you will be making the PCB?

accpool said:

Derek, have you started new thread for V 1.5 or V2.0?

have you had a chance to think about if you will be making the PCB?

Click to expand...

no, not yet. when I do I'll post a link here and update the first post. I'm actually think of renaming it to somerthing more catchy. rocket track, or something like that. I may also start over with the version in order to thoroughly confuse everyone.

as of right now, the plan is to create two pcbs: one for the tracker and one for the receiver. however that could always change.

another update:

I played around with using a cable to connect the receiver to the phone this weekend. I bought a micro usb otg cable so that I could plug a usb to xbee adapter into the phone.

The good news is I did get it working. I was able to see the gps data on the phone!

The bad news is that you still will need an external power supply to power the receiver. the phone doesn't supply 5v via the usb connector to power the adapter board and the radio. additionally, there is no software to easily make this solution work. it doesn't just work like the bt solution does.

based on these findings, I've satisfied myself bt is the best link to the smartphone. if the rx could be made small enough and not require a battery, then it would make sense. however since you will still need the battery and you'll be physically tethered to the phone, it is not worth it.

another wired option would be to use the android development kit (adk) usb interface, but this would still have the external battery requirement as well as a microcontroller in the rx. it would also eliminate any potential for use with ios devices. wifi is another possibility, but just replaces an inexpensive bt module with a more expensive wifi module, so I don't see any advantage to that. the only potential plus would be I know gps over wifi work with ios.

so bluetooth has won. if I missed any other interface, please let me know, but I'm pretty sure I've looked at all the major ones.

Derek said:

The bad news is that you still will need an external power supply to power the receiver. the phone doesn't supply 5v via the usb connector to power the adapter board and the radio.

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The USB OTG standard should allow the phone to supply power (see https://en.wikipedia.org/wiki/USB_On-The-Go -- I haven't looked into the restrictions various phones and tablets may have but I'm pretty sure the Nexus 7 provides power) but you're right that the Android USB host mode software support is pretty bad at this point, and BT is definitely easier to deal with.

My system (which was extensively documented in a thread on now-dead Rocketry Planet) uses a handheld Arduino-based receiver with an LCD display; to connect this to a tablet I just stuck a BT module in the receiver.

I tried it on my development phone - a motorola droid 4. I couldn't get it to work until I provided external power. I didn't try my nexus s or nexus 7, so it could be device dependent.

but the fact that the one phone I tried it with didn't operate as expected leads me to conclude that usb otg isn't a viable solution.

another oddity is that wiki page says otg devices should have micro ab connectors on them. all of the android devices I own (total of 5) only have micro a connectors. none have the micros ab.

the only device I've ever seen with a micro ab was on a product I designed. weird.

Derek, will any of the complete transmitter devices your working on fit in a BT-50 body tube?

I'd be down for a TX PCB. I'd like to just use my laptop to receive the data and display location. I use it for my Altimeters anyway, so it's nothing
extra to lug around. Might consider going the full setup route with the phone though. Seems it would be pretty cool to just take your phone
and walk out to the rocket.

Definitely subscribed!! I'm not an electronics guru by any stretch, but I'm pretty decent with an iron!

Ron

Leo said:

Derek, will any of the complete transmitter devices your working on fit in a BT-50 body tube?

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version 1.0 with the 3dr radios will, versions with the xbee radios won't. the xbee radio by itself won't fit in a bt-50 tube.

sorry.

AZ_Ron said:

I'd be down for a TX PCB. I'd like to just use my laptop to receive the data and display location. I use it for my Altimeters anyway, so it's nothing
extra to lug around. Might consider going the full setup route with the phone though. Seems it would be pretty cool to just take your phone
and walk out to the rocket.

Definitely subscribed!! I'm not an electronics guru by any stretch, but I'm pretty decent with an iron!

Ron

Click to expand...

that would be the simplest solution. all you need is something like this to plug into the laptop:


https://www.sparkfun.com/products/9819

Derek said:

version 1.0 with the 3dr radios will, versions with the xbee radios won't. the xbee radio by itself won't fit in a bt-50 tube.

sorry.

Click to expand...

Then that's the route I will take after I've understood what your doing

Leo said:

Then that's the route I will take after I've understood what your doing

Click to expand...

you'll probably want to change out the 9v battery to something smaller, like a lipo. that would also make the wiring a little easier. please post any questions you have!

Definitely with lipo.

I'll watch and read for now. Thanks!

Leo said:

Definitely with lipo.

I'll watch and read for now. Thanks!

Click to expand...

since version 1.0 is kind of a one off, I might be willing to part with it.

your altimeter got me thinking about diy rocket electronics in the first place!

Derek said:

since version 1.0 is kind of a one off, I might be willing to part with it.

your altimeter got me thinking about diy rocket electronics in the first place!

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I might be interested. However keep it for now. Maybe you have the chance of needing it to make more comparisons.

I'd like a fitting GPS system with my altimeter.

I must admit many all over have been inspired by my project. Quiet cool

I need to correct an earlier statement I made about the usb ports on my different android devices. I tried plugging an usb xbee adapter board into my nexus 7 and the nexus 7 doesn in fact provide the necessary 5v to power the board! I don't know how much current it is capable of supplying, but it provides something.

I also looked a little more closely at the micro usb connector on the n7 and it does have a slightly different shape than my other android devices, although it doesn't look exactly like the micro ab usb connector I've used in the past.

this discovery doesn't change anything for me as my phone will be my primary display device in the field.

update:

the n7 has a micro b connector, but it is a slightly different shape than other micro b connectors I've seen. that's what threw me off. however it does seem to support otg which means it should have a micro ab according to the spec.

another quick update:

I gave up waiting for my xbee shield to arrive and hacked another xbee adapter to connect to my bt module and I finally got to test the xbee radios last night with the smartphone. they do work, but I haven't had a chance to repeat my range testing. hopefully today or tomorrow night, but if not definitely this weekend.

and of course the tracking number for the xbee shield indicates it will be here today. figures!

I got to do some range testing with the xbee and 3dr radios this weekend. the xbee radios do have a slightly greater range, but not by a huge amount. In my neighborhood, the difference was less than 100'. these tests were with the transmitters on lying the ground.

one last test I did do though was I put the xbee transmitter on my roof (about ~14' above the ground) to see if the range improved. the results were dramatic. at just under 1/2 mile away I ran out of road and had to stop but the receiver was still picking up the signal! this is still not a clear line of sight as there were lots of leafy trees between the units.

I'm tempted to try putting the transmitter on a balcony on the beach and going for a walk up the beach. that will provide a clear line of sight to the transmitter. I'd be willing to bet the range is over 1 mile.

I went and ordered the 3dr setup (needed the 433MHz version and because of it's size).
Right now I'm testing the Venus GPS chip. I have it running at 10Hz and it seems to be going well.

Leo said:

Right now I'm testing the Venus GPS chip. I have it running at 10Hz and it seems to be going well.

Click to expand...

this one?

https://www.sparkfun.com/products/10919

the fastrax will do 10hz too, but I've left it a 1 hz as I don't see the need for faster updates for tracking. you may have to up the air rate which will also reduce the range.

Yes, as break out board.

so you got something like this:


https://www.sparkfun.com/products/11058

That's it.

Derek, referring to post# 80 , what would your guru opinion be as to which equipment you would use? i would like to get going on building one.

I'd use the xbee modules unless you really need the smallest size possible tracker, like Leo. They cost a little more and are slightly bigger, but I haven't had any issues with them not linking up and most importantly should have a greater range.

my biggest complaint with the 3dr radios is sometimes they just won't connect to one another and you need to power cycle them a few times before they link. it can be annoying.

Leo said:

That's it.

Click to expand...

what are you using for an antenna?

Derek said:

the fastrax will do 10hz too, but I've left it a 1 hz as I don't see the need for faster updates for tracking. you may have to up the air rate which will also reduce the range.

Click to expand...

For the actual first tests I'll be going 1Hz. My plan is to run 10Hz later as I want to log at this rate. Every tenth log will be used for sending tracking information to the base.

ok xbee's it is.