Simple GPS Tracker?

[Fdog]

How about the MEW Crystal Ball GPS system?

It's designed for rocketry, Tripoli approved for records, and needs no Amateur Radio license. No cell phone coverage, no APRS network, just the rocket, your smartphone and a small ground radio.

It also answers Troj's problem with not having enough hands - you view the map on your smatphone/tablet/whatever over Bluetooth, while the radio sits on the dash of your chase vehicle (or your back pocket).

I've seen it in action. Very solid, no dropouts, it just works.


All the best, James


All the best, James

 

[iter]

Your idea sounds very similar to the gps tracker I'm working on, however I plan on using bluetooth as the final link to the phone because I'm not a software engineer and I hope to leverage a lot of the stuff developed by the diy drones guys for their ground control stations (gcs). they have gcs sw for all sorts of different platforms, including android.

Derek, if you're willing to pay for a BT shield and like DIYDrones stuff, you may as well use their boards as is and forgo the trouble of building this stuff and programming it yourself. Stuff an ardupilot with their radio into your rocket, and you have a license-free system ready to go that reports GPS, air pressure, accelerometer, etc., in real time and logs all of this stuff as well.

Ari.

 

[qquake2k]

How about the MEW Crystal Ball GPS system?

It's designed for rocketry, Tripoli approved for records, and needs no Amateur Radio license. No cell phone coverage, no APRS network, just the rocket, your smartphone and a small ground radio.

It also answers Troj's problem with not having enough hands - you view the map on your smatphone/tablet/whatever over Bluetooth, while the radio sits on the dash of your chase vehicle (or your back pocket).

I've seen it in action. Very solid, no dropouts, it just works.

All the best, James

It looks nice, but $1000??? :shock:

 

[Fdog]

How hard is it to get a HAM license for the 70cm band?

The hardest part for me was finding a test nearby that matched my schedule. Given your location you are close to a couple tests per week!

The written test took me 20 minutes and cost $15. There's no more Morse code requirement for Technician or General level tests, so material is limited to the (published) test question pool. After the test, I showed up in the national database in 5 days.

If you're curious about how hard the test is, you can go to QRZ.com. You'll need to register but it's free and I haven't ever recieved spam from them. You can take the test(s) until you feel ready, I also suplemented this with a General-class study guide in book form. Consequently I ended up woefully over-prepared!

Even if you don't have an immediate need, it's worth getting. I've since found many other uses for my Amateur license besides finding wayward rockets!


All the best, James

 

[Fdog]

Well, yes, I guess you're paying for a solid system that's complete.

A BeeLine GPS, and, an APRS-enabled hand radio (with GPS) totals about $750. So I guess there's a certain "level of commitment" no matter what.


All the best, James

 

[Derek]

That is exactly what I envision for my project. I didn't know such a thing already exists.

Thanks for the link!

How about the MEW Crystal Ball GPS system?

It's designed for rocketry, Tripoli approved for records, and needs no Amateur Radio license. No cell phone coverage, no APRS network, just the rocket, your smartphone and a small ground radio.

It also answers Troj's problem with not having enough hands - you view the map on your smatphone/tablet/whatever over Bluetooth, while the radio sits on the dash of your chase vehicle (or your back pocket).

I've seen it in action. Very solid, no dropouts, it just works.


All the best, James


All the best, James

 

[Derek]

I thought about that, but the ardupilot is big, expensive and does lots of things we don't need. I'm trying to keep it cheap and simple. Basically my idea is a rocket optimized ardupilot.

Derek, if you're willing to pay for a BT shield and like DIYDrones stuff, you may as well use their boards as is and forgo the trouble of building this stuff and programming it yourself. Stuff an ardupilot with their radio into your rocket, and you have a license-free system ready to go that reports GPS, air pressure, accelerometer, etc., in real time and logs all of this stuff as well.

Ari.

 

[Derek]

It looks nice, but $1000??? :shock:

wow. I missed that part...

 

[iter]

I don't get it.

If you buy this https://store.diydrones.com/APM_2_5_Kit_p/br-ardupilotmega-05.htm and this https://store.diydrones.com/3DR_RadioTelemetry_Kit_915_Mhz_p/kt-telemetry-3dr915.htm from DIYDrones, the total is $274.98 and everything is ready to go. The radio is rock-solid (I use it in my electric R/C airplanes) and is license-free. You do need a laptop to display your flight path, but you can pre-load satellite maps using their software, so cell coverage is a non-issue.

The laptop requirement and the high cost (I feel $275 is too high in this application) are the driving factors for me to develop the system I'm describing. But if you're OK spending that, I highly recommend DIYDrone equipment.

Ari.

 

[Derek]

What don't you get? ardupilot costs $200 for a lot of functionality that we don't need.

That is the radio system I'm using and I added a $30 gps, so my airborne platform only costs about $70. That seems much more reasonable to me. I'm thinking that the floor for the rocket portion is about $50, so there isn't much money left to be saved. But ultimately, I think anything under $100 is acceptable so I'm already ahead.

I appreciate the feedback on the radio. I haven't tried outdoor range tests yet, but I so far it is working great. I bought a couple of cheap 3.5db antennas to try as well as the 2db ones.

The arduino and bt shield I already had so there is no cost associated with them. As I stated earlier, they are only for development purposes. Ultimately I'd like to connect the base station radio via usb to eliminate the additional cost and complexity associated with the bt approach. The you would just need a $30 radio and a usb cable.

They have an android gcs, so no laptop is necessary.

I think you and I have the same goals (cheap, small gps tracker). I'm looking forward to seeing how your software turns out.

Derek

I don't get it.

If you buy this https://store.diydrones.com/APM_2_5_Kit_p/br-ardupilotmega-05.htm and this https://store.diydrones.com/3DR_RadioTelemetry_Kit_915_Mhz_p/kt-telemetry-3dr915.htm from DIYDrones, the total is $274.98 and everything is ready to go. The radio is rock-solid (I use it in my electric R/C airplanes) and is license-free. You do need a laptop to display your flight path, but you can pre-load satellite maps using their software, so cell coverage is a non-issue.

The laptop requirement and the high cost (I feel $275 is too high in this application) are the driving factors for me to develop the system I'm describing. But if you're OK spending that, I highly recommend DIYDrone equipment.

Ari.

 

[mikec]

FWIW, I put a simple tracking system together for about $200 using XBee 900 MHz radio modules. See https://www.rocketryplanet.com/forums/showthread.php?t=9205

It would be fairly simple to interface the XBee to a tablet or phone on the ground side.

The 3DR radios are another option, but the XBees have significantly longer range.

 

[Derek]

I looked at the digi pro radios for this project, but I liked the form factor of the 3dr radios a little better and they are slightly cheaper. Plus, I already have some xbee radios so I thought I'd try something new.

I'm not sure about the range difference, though. both radios have the same output power so I'd expect the range to be comparable.

Derek

 

[mikec]

both radios have the same output power so I'd expect the range to be comparable.

The default 3DR data rate is much higher, leading to lower range. I think the 3DR data rate can be adjusted. Digi recently came out with a new version of the XBee Pro 900 XSC with twice the output power (200 mW) and higher sensitivity, for the same price as the older module.

 

[troj]

How hard is it to get a HAM license for the 70cm band?

Technician is all that's required -- a short test, the study guide for which is available online. https://www.arrl.org

-Kevin

 

[Derek]

The default 3DR data rate is much higher, leading to lower range. I think the 3DR data rate can be adjusted. Digi recently came out with a new version of the XBee Pro 900 XSC with twice the output power (200 mW) and higher sensitivity, for the same price as the older module.

the data rate can be adjusted, and I have already turned it down. I don't need a very high rate.

I didn't know about the newer digi modules. Thanks!

 

[bigredbee]

Not true, all that is required is a tech license.

I believe you cannot make ham devices on a technician license, you must get the general.

 

[bigredbee]

In my opinion the quickest way to roll your own GPS tracker is with the XBEE 900 Mhz radios. Just tie the output of the GPS to the input of the XBEE on the rocket side, and then the output of the XBEE goes into a laptop on the receive side. Part of the challenge is finding a GPS module that will track rapidly moving objects (if you care about accurate altitude) and making things physically robust. The entry level BRB900 does exactly this for a total price of $299 that includes transmitter, receiver, batteries, chargers, USB interfaces, etc. For just a little bit more, you can ditch the laptop and get the LCD enabled receiver.

Someone made a comment earlier about using "unlicensed radio frequencies". There's really no such thing -- either YOU need a license to operate on the amateur radio band, or the DEVICE needs to be licensed by the FCC.

The nice thing about the XBEE radios is that they are already certified by the FCC and require no license. The bad thing is they have limited range compared to what's possible using the amateur radio bands.

 

[Derek]

...(if you care about accurate altitude)...

if you care about accurate altitude, then you need to look at something other than gps.

 

[bigredbee]

At low altitudes, you are correct. But GPS is more accurate than many barometric altimeters at high altitudes.

 

[Derek]

have you thought about developing an interface for your 900 mhz gps tracker for use with a mobile phone?

 

[bigredbee]

I have no such plans, and I do not believe it's even possible.

 

[mikec]

I have no such plans, and I do not believe it's even possible.

All you have to do is figure out how to interface the XBee with the phone (as an earlier poster mentioned, Bluetooth is probably the easiest way to go) and then write an app for the phone. I've been thinking of doing this for Android, I don't think it would be difficult.

 

[cwbullet]

that is the difficult part.

 

[BEAR]

I do not know if this is what you want in your discussion, but I would like to submit something. I have a friend who thought his wife was cheating on him. He bought a small Chinese made GPS tracker for tracking his wife's car. It was smaller than a pack of cigarettes in it's case with a battery. It cost him $80. He had to purchase a telephone number for it and has a pre-paid T-Mobile phone number for the tracker. The unit finds it's location off of cell phone towers, (OK, not true GPS) to give it's location. You call the number from any phone or smart phone and it tells you where it is. After the issues in his marriage were successfully resolved, my friend did not want the device around any longer, thereby keeping his wife from finding it and asking questions that could cause arguments, so he gave it to me. I have found that I can take this out of it's case and fit it in a 38mm case and with battery, have it weigh in at less than 50gms. Here in Colorado, I have Verizon 4g coverage and T-mobile coverage at both of our launch sites. I hope to fly it next spring, and I am doing ground tests with it now. When I do fly it, I can launch it, call the phone number of the tracker, and it will tell my droid where it is. It seems to work pretty well. I hope this may be of some value to some of you. (I do have a Telemetrum, and a few other radio transmitters for my rockets, but not a BRB, and I do have my technicians license. I used www.hamtestonline.com to prepare for the technicians license and highly recommend it. KD0OVY)

 

[Reinhard]

Connecting the XBee to a Bluetooth module that supports RFCOMM (SPP) is basically not that hard. Besides the mentioned terminal, there are also Apps that support external GPS receivers (some make it available to the other apps, as it were the internal one). One annoying thing that I found out, playing with Bluetooth modules, is that they behave differently when it comes to establishing the connection. The one on the BluetootBee sends some startup data, that might confuse GPS receivers or the apps. The BTM-182 was better behaved, if I remember correctly. So far, I have played only superficially with them, so I can't say if a complete setup would work.

Reinhard

 

[awseiger]

I've been working on a simple RF beacon tracker that uses an Arduino and a simple transmitter to create something that outputs beeps, and then my callsign in morse code. Similar to the UTC broadcasts.

On the receive, it's purely analog. A few transistors hooked together to make a regenerative reciever. By using a giant loop as the tank coil, I can achieve directionality and thus tracking. Just turn kind of the direction the rocket should have landed, aim the antenna around untill you can't hear the signal, and start walking.

My plan is for the whole system to cost under $100. Alot more than super-HPR fliers could benefit from a tracking system. The only real problem with trackers today are their price tags. Definetly worth it. But to alot of people, not THAT worth it.