Featherweight GPS tracker

[Dan Griffing]

I recently purchased a Featherweight GPS tracker. I ended up purchasing an iPad 9th gen to work with the iOS app. I ended up finding using the iOS for tracking for worse than just taking the lat/long to Google Maps. But Google Maps isn't the ideal solution either. So I spent most of yesterday learning about all the iOS and Android mapping apps. Many seems like they should be perfect for the use case, including Google Maps. A lot of the time where we launch rockets is the middle of nowhere with little or no cell signal. Which is the rub, most need an internet connection for either satellite data or even to just do any form of search within the map.

In the end I found an Android app called "All-in-one Offlinemaps". It won't let me save Google map and satellite data, but it will let me save Microsoft map, satellite, and hybrid data. It also makes it fairly easy to type or copy paste lat/long into the app. I found I could use Google Lens to OCR the text out of the iOS app and then be able to copy paste into "All-in-one Offlinemaps".


My next plan is to write a basic application, probably in Golang that I recently learned. The goal is just to provide the lat/long. I am likely going to start with Linux and USB. Then follow that up with Android and Bluetooth. The first version for Android will probably just allow copy/paste, but I hope to later allow some integration with mapping apps.


@Adrian A Are you willing to share some technical data on how I might go about this via bluetooth? My plan is to open source my application by posting it to GitHub. I am also not looking to make any money off it. I would think it would be in your own self interest. Any form of Android app would be free work, and likely increase sales.

Ever since the Featherweight came out I’ve heard people who don’t like the iPhone or iOS complain or try to find other alternative.

But this would probably have been done already if it had been feasible for the size of potential customer market for the Featherweight.

And I wouldn’t expect that Adrian to see it in his business interest to give away the GPS communication protocols so that someone else can develop an app that can compete with his own offering. After all, he is doing this as a business instead of a community service for high power rocketry.

 

[kjhambrick]

Nathan --

If you're talking about the Featherweight Blue Raven Android App, there are a number of Development threads here in this sub-forum.

If you're talking about what I was working on, then abandoned here goes ...

When I bought my Blue Raven ( Apr 26, 2023 ) the FIP Program didn't work because it was programed for one of the earlier Ravens ( not sure which version ).

But I was able to connect via Putty on Win10 and minicom on Linux and I could snag the data stream on either OS, so I figured that with the Blue Raven Manual and a little code, I could come up with a Linux Program to get at my Data.

I started with the C Source code for an unreleased AltAcc development program called protalk.c -- this was a debugging program for the AltAcc which enabled 'babel mode' so I could mess with the AltAcc's raw readings.

Program protalk.c captured 256 pairs of AltAcc pressure and acceleration data to a text file ( 16 seconds worth of 16-Hz data ) and it was the basis for program probate.c -- the AltAcc Calibration Program.

I modified a copy of protalk.c to capture one minutes worth of Blue Raven data to a text file so I could test my USB comms.

That program worked fine so I was all set to do something significant.

There was another AltAcc program -- proread.c which was used to download the AltAcc Flight Data that I was going to modify to issue the commands to download the Blue Raven summary, low_rate and high_rate data sets to text files and then I would eventually do accelerometer calibrations and etc.

This is where I stopped ( mid-May ) because Adrian released the Bluetooth Download App for Android which did everything I wanted.

Trust Adrian -- the Featherweight development cycle is pretty darn quick and from what I can see he is peddling as fast as he can

-- kjh

 

[manixFan]

@kjhambrick: I’m pretty sure he’s talking about the iFIP program for the Featherweight trackers. As you are well aware, that only works on iOS. In spite of never having actually used it to track a rocket (unless I misread his posts), he’s concerned it will have him walking in circles. He found the interface too difficult to use or trust, I’m not sure which.

There is no doubt it would be better and easier if there was an official Android app, and I’m hopeful there will be one sooner than later. But I think it’s poor forum etiquette to start trashing a well known and respected developer/manufacturer in the first two posts made, while not having any actual real world experience with the product. It’s possible to make valid criticisms without making unfounded accusations.


Tony

 

[Nathan Grennan]

@Nathan Grennan, what are you flying the tracker in?

I am just testing it on the ground, no rocket at the moment. It will launch in my level 1 rocket on July 16th.

 

[Nathan Grennan]

@kjhambrick: I’m pretty sure he’s talking about the iFIP program for the Featherweight trackers. As you are well aware, that only works on iOS. In spite of never having actually used it to track a rocket (unless I misread his posts), he’s concerned it will have him walking in circles. He found the interface too difficult to use or trust, I’m not sure which.

There is no doubt it would be better and easier if there was an official Android app, and I’m hopeful there will be one sooner than later. But I think it’s poor forum etiquette to start trashing a well known and respected developer/manufacturer in the first two posts made, while not having any actual real world experience with the product. It’s possible to make valid criticisms without making unfounded accusations.


Tony

Yes, I have not launched with the tracker. But I see no reason why it shouldn't be testable on the ground without a launch. It is just a GPS tracker. It is sharing the lat/long, and trying to navigate the person to the tracker.

 

[Nathan Grennan]

Ever since the Featherweight came out I’ve heard people who don’t like the iPhone or iOS complain or try to find other alternative.

But this would probably have been done already if it had been feasible for the size of potential customer market for the Featherweight.

And I wouldn’t expect that Adrian to see it in his business interest to give away the GPS communication protocols so that someone else can develop an app that can compete with his own offering. After all, he is doing this as a business instead of a community service for high power rocketry.

There is no GPS communication magic. All I need is the bluetooth configuration so I can get the equivalent of the GPS data that I can already get from the USB port. I will probably be able to figure it out on my own, it will just be harder, if he won't share the bluetooth configuration.

 

[Dan Griffing]

Years. From Day 1. There are several threads on this. Many purchasers see the same pitfalls as you mentioned.

I think some of the issues arised from the fact that the software developer was learning to code in iOS while creating/maintaining the Featherweight GPS software. If I am not mistaken, it was his first major project in the iOS platform.

I ran into some of the same troubles as you, and I am a tech-savvy engineer. The FW was my 3rd model of rocket GPS that I purchased, not my first. Yet, some things were not intuitive (and not documented), like the elevation bubble. I learned about that here in the forum. Overall, the features of the FW are pretty clever, once you figure them out.

@Conway Stevens summed it up pretty well - the software is a dedicated compass for the FW GPS. I got one mainly for the data logging, but that can get wonky, too.

I don't think Adrian will give you access to the data other than the ground station capability mentioned by @kjhambrick.

The new Blue Raven integration will hopefully solve the past problems.

Look at Missileworks T3 and Eggfinder for GPS units that are Android-capable. Many, many threads on the forum.

Not sure what you mean by "margin of error." All consumer GPS units are good to about +/- 3m. Once you are that close, you should see your rocket.

I’ve been using the Featherweight since it first came out after switching from two Eggtimer gps units.

It’s a great gps but what I like best is the audio callouts of the altitude, apogee and descent velocities in whatever voice I choose. It’s not as advanced as “Kate” but it’s half the price and you can buy them.

I connect my iPhone to a Bluetooth speaker and folks gather around the hear every launch. The apogee and downward velocity confirm that the drogue chute has opened even when the rocket is too high to see. And the app always leads me to where the rocket has landed, even in hilly terrain.

 

[Nathan Grennan]

Nathan --

If you're talking about the Featherweight Blue Raven Android App, there are a number of Development threads here in this sub-forum.

If you're talking about what I was working on, then abandoned here goes ...

When I bought my Blue Raven ( Apr 26, 2023 ) the FIP Program didn't work because it was programed for one of the earlier Ravens ( not sure which version ).

But I was able to connect via Putty on Win10 and minicom on Linux and I could snag the data stream on either OS, so I figured that with the Blue Raven Manual and a little code, I could come up with a Linux Program to get at my Data.

I started with the C Source code for an unreleased AltAcc development program called protalk.c -- this was a debugging program for the AltAcc which enabled 'babel mode' so I could mess with the AltAcc's raw readings.

Program protalk.c captured 256 pairs of AltAcc pressure and acceleration data to a text file ( 16 seconds worth of 16-Hz data ) and it was the basis for program probate.c -- the AltAcc Calibration Program.

I modified a copy of protalk.c to capture one minutes worth of Blue Raven data to a text file so I could test my USB comms.

That program worked fine so I was all set to do something significant.

There was another AltAcc program -- proread.c which was used to download the AltAcc Flight Data that I was going to modify to issue the commands to download the Blue Raven summary, low_rate and high_rate data sets to text files and then I would eventually do accelerometer calibrations and etc.

This is where I stopped ( mid-May ) because Adrian released the Bluetooth Download App for Android which did everything I wanted.

Trust Adrian -- the Featherweight development cycle is pretty darn quick and from what I can see he is peddling as fast as he can

-- kjh

Is "Bluetooth Download App for Android" in the Play Store? Is there a URL for the apk?

Edit: I found the Blue Raven app. I see it too is in Firebase, not the Play Store. :\

 

[DaHabes]

I would say given it goals and style, it is good enough. Will it get you within the margin of error that you generally see from Google Maps? Yes. Is that good enough to find a rocket? Very likely. On the other hand my experience is that if you don't understand the limitations caused by the margin of error it will lead you on a wild goose chase. It will lead you left, then right, then left, then straight, then back left. It will keep feeding you new data and you will circle the general area.

I also found the black circle that I was trying to keep the red/green circle in at the bottom very non-user friendly. In that it wasn't just the red/green circle moving, but the black circle too. Sometimes both would move off the edge of the screen. So it was more complicated that just following the arrow. I did try ignoring this, and going to what I was saying above the arrow would lead me astray and in circles.

Speaking of the iOS app. That it is only installable via TestFlight is very weird. I work in the tech industry. I have worked with TestFlight before. It is meant for internal use only not external use. I am surprised Apple hasn't shut the account or app down. I would love to hear what has prevented them from getting Apple to approve the app into the App Store. I get it makes it easier and faster to get code out to users, but that sounds like the need for a beta program not what I would call beta only.

The alternative that I found was just to take the given lat/long to a mapping app and it would have directly gotten me to within my own arm span of it. Which I think would be simpler, and better.

I purchased the iPad just to use my Featherweight. I did look into getting a iPhone off Facebook Marketplace and Craigslist. My concern with buying $100 phones off someone was "What are the odds they were stolen?". Another concern was if such a cheap phone was going to be supported by Apple for much longer. I know Apple is one of the best about support, but the cheapest phones were "iPhone 7"s. My primary phone is Android. I also have multiple old Android phones. I even own a Samsung Android tablet. Edit: I also wanted to get familiar with the system ASAP, because I have a launch on July 16th for my level one certification. I purchased the Featherweight, because my biggest concern is losing the rocket and then failing the certification.

The FW app is more than adequate. I have never had it fail me in finding a rocket. Best thing about the app? When the bird is in the air and out of sight, it still points to it, so you can find it in the air when it comes back into view. This is especially valuable when the upper-level winds are 10x what they are at ground level; you'll never locate it in the air without this feature. It is always better to have a visual before it lands and not rely solely on the GPS coordinates. The app does that for you.

 

[kjhambrick]

Nathan --

Changing gears here ...

Can you share your plans for your Level 1 Flight this Sunday ?

-- kjh

 

[Conway Stevens]

Yes, I have not launched with the tracker. But I see no reason why it shouldn't be testable on the ground without a launch. It is just a GPS tracker. It is sharing the lat/long, and trying to navigate the person to the tracker.

Trying to test this trackers functionality on the ground is like trying to determine how a car will run/drive while sitting parked and never moving.

Nathan, how many satellites do you have lock with? On the ground depending where you are you may have poor satellite view. If thats the case then its not going to work right. At home i am lucky if i get between 5 to 6. At the launch site i usually end up with 15 to 24. Also the flight movement changes things in how it operates. Your not getting any of the triggers gor gps track from movement. There is no vocal output until flight, the horizontal/azimuth reading does not function til its in the air. Movement/flight and the speed it moves is what updates the position and creates a trackable function. Without movement in flight your not utilizing the software and how it updates position and track signal unitil you fly it.

Without flying it i think you're jumping the gun on what it does or how it works. Plus criticizing the app or its function and developer with never really using it. Use it several times in flight get used to it and how it works.

 

[Conway Stevens]

Is "Bluetooth Download App for Android" in the Play Store? Is there a URL for the apk?

Edit: I found the Blue Raven app. I see it too is in Firebase, not the Play Store. :\

Nope not in playstore yet. Its pretty new. The Blue Raven was just released as a product a few months ago the Featherweight web page has release notes on its software a its still under work and new features/functions/debugging and other stuff are being worked out.

 

[Nathan Grennan]

Nathan --

Changing gears here ...

Can you share your plans for your Level 1 Flight this Sunday ?

-- kjh

I built a LOC IV rocket with a 38mm motor mount. I have already flown it at a club event with a couple G motors. I have purchased 38mm H100 motors. I have run the data through OpenRocket. I expect it to go up around 1100 feet with the H100 motor. I don't have a drogue chute. Hence why I have the GPS tracker. My biggest concern is not recovering the rocket. I do have an altimeter to get the altitude for the flight.

The launch site has hills/mountains three miles east, and others five miles southwest. I expect the rocket will go about one mile away at most. Given that the area is so flat recovering the rocket should be pretty straight forward.

Since I previously launched it I added some fluorescent yellow paint on the tip of the nose cone, and stripes on the body. The parachute is red, and so has good visibility. I have a swivel to avoid the parachute lines tangling.

The only thing I really have left to figure out is where to put the GPS tracker in the rocket. The two choices are the payload bay or in the nose cone. The payload bay is the easy answer. The nose cone would involve cutting into the bottom to make a hole big enough to get the tracker in, and coming up with some way of securing it inside.

 

[kjhambrick]

Nathan --

I like the LOC-IV a lot and I REALLY like the H100-W Motor ( 2+sec of beautiful smoke and flame and it is LOUD !

One good thing about your 1100 ft expected Altitude is that you'll get some experience with what you can see in the air -vs- what you see on the screen ...

One Q: How much does your LOC-IV weigh without a motor ?

As for locating your FW GPS, I'll leave that to the experts here -- I am still a Walston Guy who attaches his trackers to the drogue harness inside a coupler tube with a duck-tape sheath for the antennas

-- kjh

 

[Conway Stevens]

I built a LOC IV rocket with a 38mm motor mount. I have already flown it at a club event with a couple G motors. I have purchased 38mm H100 motors. I have run the data through OpenRocket. I expect it to go up around 1100 feet with the H100 motor. I don't have a drogue chute. Hence why I have the GPS tracker. My biggest concern is not recovering the rocket. I do have an altimeter to get the altitude for the flight.

The launch site has hills/mountains three miles east, and others five miles southwest. I expect the rocket will go about one mile away at most. Given that the area is so flat recovering the rocket should be pretty straight forward.

Since I previously launched it I added some fluorescent yellow paint on the tip of the nose cone, and stripes on the body. The parachute is red, and so has good visibility. I have a swivel to avoid the parachute lines tangling.

The only thing I really have left to figure out is where to put the GPS tracker in the rocket. The two choices are the payload bay or in the nose cone. The payload bay is the easy answer. The nose cone would involve cutting into the bottom to make a hole big enough to get the tracker in, and coming up with some way of securing it inside.

Instead of making crazy work and a potential issue in the nose cone I'd recommend the Av bay with the altimeter.

 

[Dan Griffing]

Yes, I have not launched with the tracker. But I see no reason why it shouldn't be testable on the ground without a launch. It is just a GPS tracker. It is sharing the lat/long, and trying to navigate the person to the tracker.

Some of the Featherweight features in the app (such as the audio reporting of the ascent, apogee and descent) are activated by the detection of launch conditions. These features cannot be tested on the ground. The lock-in of the landing gps location after landing is also one of these features.

 

[Nathan Grennan]

Trying to test this trackers functionality on the ground is like trying to determine how a car will run/drive while sitting parked and never moving.

Nathan, how many satellites do you have lock with? On the ground depending where you are you may have poor satellite view. If thats the case then its not going to work right. At home i am lucky if i get between 5 to 6. At the launch site i usually end up with 15 to 24. Also the flight movement changes things in how it operates. Your not getting any of the triggers gor gps track from movement. There is no vocal output until flight, the horizontal/azimuth reading does not function til its in the air. Movement/flight and the speed it moves is what updates the position and creates a trackable function. Without movement in flight your not utilizing the software and how it updates position and track signal unitil you fly it.

I don't know how many satellites I had at the time I was testing it in the park. What I can tell you is by just going off the lat/long given by the iOS app, and plotting that in Google Maps it gave me an extremely accurate location. I had hand placed the tracker, in a plastic ziploc bag, in the grass, and hence I knew where it was.

There are two methods.

One, use the app and follow what the arrow says. It is directing you via the arrow based on real-time data. GPS data naturally has a margin of error, and sometimes you get a very noticeably off lat/long returned. I have seen this while further testing it in my backyard. The tracker is in a fixed location with good sky visibility. It won't move in reality unless I move it. Most lat/long readings are within 10 feet. Yet every so often there will be one that can be up to about 100 feet off in any direction. During my experiment in the park I suspect the app and arrow direction were suffering from bad real-time data. The value of real-time data during flight is clear, but in most circumstances once it has touched down real-time data has a much higher risk of misleading you given the 100 square feet margin of error.

Two, read the lat/long from the app and plot it in some mapping software. During an actual launch I expect this would actually have two phases. The first phase is while it is in the air, and you either loose signal based from a combination of distance and touch down. So I will get the lat/long of where it was seen last. I can then get myself to around that location. The second phase will be at the last known location hopefully getting the signal again for a second reading. Then just repeat the process. Take the lat/long, map it, and travel to it. There could be edge cases here, but those are the basics.

I think the second method is much simpler, and less error prone. This would be especially true if you filter the lat/long for outliers. Which is what I have already done in my Golang/Linux code, and will do in my Android code if I can figure out how the bluetooth works. I did make some serious progress on bluetooth last night.

 

[Nathan Grennan]

Some of the Featherweight features in the app (such as the audio reporting of the ascent, apogee and descent) are activated by the detection of launch conditions. These features cannot be tested on the ground. The lock-in of the landing gps location after landing is also one of these features.

The lack of a lock without a launch I would consider a issue. I could see circumstances where either the battery in the iOS device dies, the app crashes, etc where you won't be in "launch mode" and yet you will still want to track down your rocket.

 

[watheyak]

I was trying to avoid weighing in on this but here goes...

These are all solutions with no problem.

Even without a launch detect you can still track your rocket just fine. So can everyone else with a Featherweight tracker which is a great feature. I've also never had the app crash. And I remember to charge my phone.

Also it seems much simpler to deal with an occasional 100' error that lasts a few seconds than to write an entire app using super-sleuthed Bluetooth info. And even if you had the lat/long in a mapping app, your phone GPS is still going to suffer the same errors, leading you astray for whole seconds at a time.

I think the overwhelming consensus of users is that the current app leads you straight to your rocket. I have had 100% success with startling accuracy to great distances. It trounces all other GPS units on the market in this area.

Thebalp is also the best BY FAR of any other GPS unit on the market. Despite the TestFlight and iphone only issues. Maybe I'm a bit jaded, but I used to wander through the desert with a handheld transceiver connected to a laptop trying to do what you do. Not only is putting lat/long into a map app a step backwards, it's not the way I would ever want to go find a rocket. Not anymore.

I highly recommend that you try the whole process out in actual conditions before reinventing the wheel.

 

[Conway Stevens]

I don't know how many satellites I had at the time I was testing it in the park. What I can tell you is by just going off the lat/long given by the iOS app, and plotting that in Google Maps it gave me an extremely accurate location. I had hand placed the tracker, in a plastic ziploc bag, in the grass, and hence I knew where it was.

Again this is about learning the function of the App. If you go the the satellite screen. Aka the first screen it will tell you how many satellites that have a lock as well as how strong the connection is between the ground station and the tracker.

There are two methods.

One, use the app and follow what the arrow says. It is directing you via the arrow based on real-time data. GPS data naturally has a margin of error, and sometimes you get a very noticeably off lat/long returned. I have seen this while further testing it in my backyard. The tracker is in a fixed location with good sky visibility. It won't move in reality unless I move it. Most lat/long readings are within 10 feet. Yet every so often there will be one that can be up to about 100 feet off in any direction. During my experiment in the park I suspect the app and arrow direction were suffering from bad real-time data. The value of real-time data during flight is clear, but in most circumstances once it has touched down real-time data has a much higher risk of misleading you given the 100 square feet margin of error.

Your assumption of it using only real time data is incorrect. When the ground station and tracket have line of sight or are able to pick up signal with each other. It will use the live data. Should the signal get lost. Such as loss of quality of transmission from the tracker to the ground station. Example. I flew a rocket to 32,000ft agl and had good track up and down to the ground. I had 21 sats connected. But once the rocket landed on hilly distant terrain about 5.2 miles away the live data to the ground unit stopped. But what it used was last known good coordinates. It pointed me to that and again as i got closer i could see the arrow change and point and distance got smaller. Once i got to an area where the 2 units established signal with each other it changed a little but guided me right to the rocket within about 5 ft from it.

Your testing is flawed and the issue you have is not existant due to such. Learn the app. Use it and enjoy. You will find it works awesome. I have also never had the app crash, battery run dead. Btw the App tells you the base station voltage and the tracker voltage so you know what they are and your phone should also show charge. I can usually get 3 flights from a 600/800 mah 1s battery and the base station and the phone.

Two, read the lat/long from the app and plot it in some mapping software. During an actual launch I expect this would actually have two phases. The first phase is while it is in the air, and you either loose signal based from a combination of distance and touch down. So I will get the lat/long of where it was seen last. I can then get myself to around that location. The second phase will be at the last known location hopefully getting the signal again for a second reading. Then just repeat the process. Take the lat/long, map it, and travel to it. There could be edge cases here, but those are the basics.

I think the second method is much simpler, and less error prone. This would be especially true if you filter the lat/long for outliers. Which is what I have already done in my Golang/Linux code, and will do in my Android code if I can figure out how the bluetooth works. I did make some serious progress on bluetooth last night.

Again... no one but you appears to see an issue with any of it or its use. And you havent used it yet? Not sure how you judge it having an issue.

As Watheyak mentioned seeing lots of fixes for problems that dont exist.

 

[watheyak]

Again this is about learning the function of the App. If you go the the satellite screen. Aka the first screen it will tell you how many satellites that have a lock as well as how strong the connection is between the ground station and the tracker.



Your assumption of it using only real time data is incorrect. When the ground station and tracket have line of sight or are able to pick up signal with each other. It will use the live data. Should the signal get lost. Such as loss of quality of transmission from the tracker to the ground station. Example. I flew a rocket to 32,000ft agl and had good track up ahd down to the ground. I had 21 sats connected. But once the rocket landed on hilly distant terrain about 5.2 miles away the live data to the fround unit stopped. But what it used was last known good coordinates. It pointed me to that and again as i got closer i could see the arrow change and point and distance got smaller. Once i got to an area where the 2 units established signal with each other it changed a little but guided me right to the rocket within about 5 ft from it.

Your testing is flawed and the issue you have is not existant due to such. Learn the app. Use it and enjoy. You will find it works awesome. I have also never had the app crash, battery run dead. Btw the App tells you the base station voltage and the tracker voltage so you know what they are and your phone should also show charge. I can usually get 3 flights from a 600/800 mah 1s battery and the base station and the phone.






Again... no one but you appears to see an issue with any of it or its use. And you havent used it yet? Not sure how you judge it having an issue.

As Wayne mentioned seeing lots of fixes for problems that dont exist.

Oops! I don't want Wayne pinned for that snarky response. That was me, Scott Wathey. Dunno why my sig doesn't have my name anymore. I'll fix it.

 

[SkyFire]

I lost an Airstrike 354 flying a CTI J430. It was found in the desert 9 months later in the desert by a construction worker. (See pic)
After that launch I got a Featherweight tracker.
Have been walking right to my rockets ever since!

 

[Conway Stevens]

Oops! I don't want Wayne pinned for that snarky response. That was me, Scott Wathey. Dunno why my sig doesn't have my name anymore. I'll fix it.

I knew it was you somehow auto correct made your screen name Wayne. Even though i know Wayne as well that flys with you down in AZ. Lol.

Snarky? Lol. No.. good advice

 

[ONAWHIM]

Back to @Nathan Grennan , best wishes on your cert flight.

I am adapting a LOC RNWS (removable nose weight system) and repurposing it as an avionics bay for tracking using the Featherweight GPS tracker. Perhaps that concept is a little over the top but I like to try stuff.
I have taken the nose cone with the tracker installed and went hunting for it. It works.

As others have pointed out trust the tracker system to get you to your rocket.

 

[Nathan Grennan]

I was trying to avoid weighing in on this but here goes...

These are all solutions with no problem.

Even without a launch detect you can still track your rocket just fine. So can everyone else with a Featherweight tracker which is a great feature. I've also never had the app crash. And I remember to charge my phone.

These just come across as never happened to me and excuses.

Also it seems much simpler to deal with an occasional 100' error that lasts a few seconds than to write an entire app using super-sleuthed Bluetooth info. And even if you had the lat/long in a mapping app, your phone GPS is still going to suffer the same errors, leading you astray for whole seconds at a time.

You touch the core issue. Ideal with 10 feet measurements vs worst case real-time 100 square feet measurements. You could call this small, but I think it could save people some time.

I think the overwhelming consensus of users is that the current app leads you straight to your rocket. I have had 100% success with startling accuracy to great distances. It trounces all other GPS units on the market in this area.

Thebalp is also the best BY FAR of any other GPS unit on the market. Despite the TestFlight and iphone only issues. Maybe I'm a bit jaded, but I used to wander through the desert with a handheld transceiver connected to a laptop trying to do what you do. Not only is putting lat/long into a map app a step backwards, it's not the way I would ever want to go find a rocket. Not anymore.

I highly recommend that you try the whole process out in actual conditions before reinventing the wheel.

My strongest motivation is to get rid of needing iOS. I think there is an untapped market of Android users who would be interested in Featherweight without the iOS requirement. I say this, because I have talked to one. It has a secondary benefit of letting me use my Android phone instead of a tablet. I have already talked about why I didn't go with an iPhone. I am also learning things, and that is fun. I know more about how bluetooth works than I did before. I have also learned how you can debug bluetooth on an iPad with a MacOS laptop. I have gotten more experience with writing Golang. I have learned more about offline mapping apps on both iOS and Android. Sometimes it is about the journey, not the destination.

I have heard some talk of Adrian putting the iOS app in the App Store or making an Android app. Given that I clearly see the product of the Featherweather GPS tracker has been around for five years, I am not holding my breathe.

I do this kind of stuff professionally. If this was work, I would agree with you. But I would also be pushing Adrian do things like get it into the Play Store if he was my co-worker. Given this is personal, not professional, and it is my own free time I am going to do it. I am interested in writing my own Android code using Bluetooth if possible. If it gets well enough I will open source and share it. I will even put it in the Play Store.

I have had thoughts of selling the iPad if I can write my own Android app. On the other hand I have considered writing my own iOS app, and publishing it to the App Store. This all hinges on if I am successful in making something usable.

I also don't care if people don't use my theoretical Android app. This is part of the idea of open source. Scratch your own itch, and share with others. They can take it or leave it.

 

[Nathan Grennan]

Back to @Nathan Grennan , best wishes on your cert flight.

I am adapting a LOC RNWS (removable nose weight system) and repurposing it as an avionics bay for tracking using the Featherweight GPS tracker. Perhaps that concept is a little over the top but I like to try stuff.
I have taken the nose cone with the tracker installed and went hunting for it. It works.

As others have pointed out trust the tracker system to get you to your rocket.

Thank you.

Yeah, I am already thinking about RNWS for post level 1.

 

[Nathan Grennan]

Again this is about learning the function of the App. If you go the the satellite screen. Aka the first screen it will tell you how many satellites that have a lock as well as how strong the connection is between the ground station and the tracker.

I am aware. I just wasn't looking at it at the time.

Your assumption of it using only real time data is incorrect. When the ground station and tracket have line of sight or are able to pick up signal with each other. It will use the live data. Should the signal get lost. Such as loss of quality of transmission from the tracker to the ground station. Example. I flew a rocket to 32,000ft agl and had good track up and down to the ground. I had 21 sats connected. But once the rocket landed on hilly distant terrain about 5.2 miles away the live data to the ground unit stopped. But what it used was last known good coordinates. It pointed me to that and again as i got closer i could see the arrow change and point and distance got smaller. Once i got to an area where the 2 units established signal with each other it changed a little but guided me right to the rocket within about 5 ft from it.

I understand it has worked for others. But I have also heard others talk about using the lat/long in a mapping method too. I am not saying the first method can't work. I am saying given my experience, even if it is niche, I have seen it's issues. I do understand it may work better during an actual flight. Reproducibility comes from being able to do things repeatedly. Launching rockets requires me to go out the middle of nowhere on certain days to fly with a group. That isn't easily reproducible.

Your testing is flawed and the issue you have is not existant due to such. Learn the app. Use it and enjoy. You will find it works awesome. I have also never had the app crash, battery run dead. Btw the App tells you the base station voltage and the tracker voltage so you know what they are and your phone should also show charge. I can usually get 3 flights from a 600/800 mah 1s battery and the base station and the phone.

I don't think my testing is flawed. I would agree it is incomplete. I agree I have more things to learn.

Again... no one but you appears to see an issue with any of it or its use. And you havent used it yet? Not sure how you judge it having an issue.

As Watheyak mentioned seeing lots of fixes for problems that dont exist.

This is a very small sample size. There are also many different possible variables that could affect the outcome like app version, iOS software version, iPhone vs iPad, iPhone hardware version, iPad hardware version, compass calibration, each persons exact device can have slightly unique behavior, my exact ground station, my exact tracker, location can matter, etc. A classic professional issue that is a meme, works on my laptop.

Edit: One factor that could affect how well the app works, does the device have a cell signal. I am using an iPad without a cellular chip. Most people are probably using an iPhone. Part of the reason I say this is it is part of what I learned in the process of trying to deal with mapping apps, and learned just how hard it can be to get them to work well without a cell signal.

 

[manixFan]

I’ve been using the Featherweight since it first came out after switching from two Eggtimer gps units.

It’s a great gps but what I like best is the audio callouts of the altitude, apogee and descent velocities in whatever voice I choose. It’s not as advanced as “Kate” but it’s half the price and you can buy them.

I connect my iPhone to a Bluetooth speaker and folks gather around the hear every launch. The apogee and downward velocity confirm that the drogue chute has opened even when the rocket is too high to see. And the app always leads me to where the rocket has landed, even in hilly terrain.

As a way to backup flight data in case all goes wrong, I screen record the iFIP for all my flights. I posted a how-to elsewhere, but it’s actually really simple. The main two items are making sure audio is not muted and screen sleep is disabled. In addition to the iFIP voice, you can also choose to record audio from the microphone as well, which can be useful to record audio notes during the flight.

For what it’s worth, below is a screenshot with both the directional arrow and elevation bubble green while tracking a descent that started at 24,500’.


Tony

For those who aren't familiar with the software, the green arrow at the top means the phone is pointed at the the rocket, the green bubble indicates the phone is being held at roughly the same elevation as the rocket appears from that location. (The indicators turn red if they are far off the rocket.) I have found it to be very useful feedback. The other values should be self-explanatory. (Of course the iFIP makes a CSV file of flight data, but the screen recording is more immediately available.)

 

[thzero]

Already done via blueraven software.

As a dedicated Android user, I think there is a lot of grasping at straws in the thread. Last thing, even on my level 2 flight, was iOS and the app crashing. Of course, as things go, didn't need it on that flight.

The device does not require cell service. I use an older iphone without any type of cell service.

And frankly, 1000' in altitude? You really don't need a tracker. Sure adds a level of comfort but with a 4" rocket like that shouldn't have an issue. Have never put one in my micro magg even when running Hs on it.

But as far as mounting... Cut the base off the nose cone, it's plenty sturdy, and shove a centering ring in above the shoulder. Then you have options to create a plywood sled that you bolt into centering ring. Did that on my level one, and bunch of other rockets including the above micro magg and works just fine.

P.s. think you'll find that there are quite a few people here that do software of all sorts here both "professionally" and "unprofessionally". But good luck, especially with golang on Android.

 

[Buckeye]

I have had 100% success with startling accuracy to great distances. It trounces all other GPS units on the market in this area.

Thebalp is also the best BY FAR of any other GPS unit on the market.

Do you have any evidence and data to support these claims? I started with GPS recovery in the early days of 2009 or so. I use two other brands of GPS in addition to the Featherweight, and they are all equally good in finding my rockets. Many of my recoveries are measured in miles. I would say accuracy is the same for every civilian GPS device: +/- 3m.

I haven't tried the "Thebalp" unit, so I can't comment on that one.