New tracker range test result

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$130 per tracker.

A tracker can be used at either end of the link. An optional ground station enclosure that includes a large battery, battery charger and external switch will go for $40. More photos and info soon. <snipped for brevity>
So $300 for both units and the case. I need to replace an RDF tracker I lost at Airfest which will cost me $140. So for the same price as an RDF I can get a full GPS transmitter. What's not to like?

Of course a big question is can the base station quickly switch between two transmitters? Of course I'm thinking of tracking a 2 stage where the booster is expected to get significant altitude and a GPS is warranted. That would really be a great setup.

And it sounds like a user could rig up their own 'base station box' if desired. Is that correct? Not sure it's worth the savings but I already have some interesting ideas for a case.

Looking forward to these going live on the website...


Tony
 

So $300 for both units and the case. I need to replace an RDF tracker I lost at Airfest which will cost me $140. So for the same price as an RDF I can get a full GPS transmitter. What's not to like?

Looking forward to these going live on the website...

Tony

Thanks for the support, guys.

And it sounds like a user could rig up their own 'base station box' if desired. Is that correct? Not sure it's worth the savings but I already have some interesting ideas for a case.
Tony

Yes, that's correct. Also, let's say you have trackers installed in a few different rockets at the field and you decide to lend a system to a buddy to use in a drag race. You will be able to use the phone app to turn a tracker that's installed in one of your rockets into a ground station that connects to your buddy's phone, without even taking it out of its av-bay.

Of course a big question is can the base station quickly switch between two transmitters? Of course I'm thinking of tracking a 2 stage where the booster is expected to get significant altitude and a GPS is warranted. That would really be a great setup.

We're definitely planning to have the phone app make it easy to monitor multiple trackers that are in flight at the same time, probably just by swiping the screen left or right to pull up the screen for the other tracker. As far as the hardware goes, the most robust way to do this would dedicate a ground station for each stage, and the data from both stages gets combined in the phone. The advantage with this approach is that each ground station can dedicate its airtime to each stage the way it would for a single-stage flight.

Here's a diagram:
ZAR4tpM.png


But there is another advanced feature we're planning that could provide an alternative... more on this soon.
 
I probably missed it, but what is the prefer power source for this guy:

1) ?S Lipo and what is the drain roughly (mA/h)?
2) Will you be selling a recommended battery with it?

This thing is super cool, and has changed my BF plans...must maintain some reserve funds.
 
I probably missed it, but what is the prefer power source for this guy:

1) ?S Lipo and what is the drain roughly (mA/h)?
2) Will you be selling a recommended battery with it?

This thing is super cool, and has changed my BF plans...must maintain some reserve funds.

1) 1S Lipo battery, about 0.07 Amps drain for the tracker and less when set up as a ground station.
2) Probably. The battery that will come with the ground station enclosure is this one:

https://hobbyking.com/en_us/turnigy...-w-2-pin-jst-ph-connector.html?___store=en_us

which should power a ground station for ~24 hour continuously.
For a battery powering a tracker, I like the 400 mAhr ones from Sparkfun:
https://www.sparkfun.com/products/13851.

It can also plug into the connector that's behind the battery door in the ground station enclosure for charging.
 
I have an updated website. I'm in the process of getting my normal www.featherweightaltimeters.com domain transferred to a new registrar, so in the meantime I set up the new site on a temporary domain, here:




This has more information about current and future features. I'll go into more detail on some of the more interesting ones over the next few days.

Edit: The domain transfer is complete so I updated the link in the logo above back to www.featherweightaltimeters.com
 
I had lunch today with a group of rocket guys. I showed them the tracker and we talked about the features. The response was very positive. The additional features will really add a lot of value. The ability for a single unit to be both a transmitter and a ground station was very appealing to us since we almost always fly as a group and the flexibility of units will be a big help vs. the wide variety of systems we now use.

Some of the advanced features are very powerful, including the relay function. I'm really interested to hear how that works. Could be very useful for sites like Argonia and BALLS.


Tony

ps: good luck with transferring the site. I've done that several times and it's always a huge PITA.
 
Some of the advanced features are very powerful, including the relay function. I'm really interested to hear how that works. Could be very useful for sites like Argonia and BALLS.

For those who haven's seen it yet on the website, here's a diagram of the relay function:

BHJ617n.png


Here's how it works:
When the tracker sends GPS data to the ground station, it does it in a cycle. First the tracker sends data to the ground station, then the Ground station sends back an acknowledgement to the tracker, and then there is some time available for listening on other radio channels dedicated for public coordination. During that time, the tracker listens for other trackers and the ground station listens for other ground stations. The trackers are listening on a "lost and found" channel that the trackers transmit on when they are out of contact with their phone and ground station. When a tracker hears from a found rocket, it sends that data back to its own ground station and then to the phone app. When a phone app sees that a new rocket has been found, it tells the ground station to transmit that information during the public coordination period, which allow all the other ground stations in range to get the same information.

This might sound complicated, but it will all be happening in the background so if your rocket lands behind a hill, you'll just see a new updated location of your rocket as soon as another rocket carrying a Featherweight tracker launches into a clear line of sight to the your rocket.

A caveat here is that the code isn't done yet, though I have been planning for this since I started about 10 months ago. At BALLS this year, we did test out part of it by stashing a tracker on the playa out of direct radio range from the flight line. Then when we flew Kevin's rocket, it picked up data packets from the "lost" rocket.
 
Yup. I'd volunteer to fly a solar powered repeater blimp tethered to my pop up stakes at Airfest next year :)
 
Adrian, this looks simply awesome. Exactly what I would expect from Featherweight and then some.

Couple of questions:

To use the apps (either the currently available iPhone one, or the "still-to-come" android one), I'm assuming they will work without a data plan (or cell service), yes? What about using an iPad?

I know the final production version doesn't quite exist yet, but what will be the dimensions and weight?

s6
 
Adrian, this looks simply awesome. Exactly what I would expect from Featherweight and then some.

Couple of questions:

To use the apps (either the currently available iPhone one, or the "still-to-come" android one), I'm assuming they will work without a data plan (or cell service), yes? What about using an iPad?

I know the final production version doesn't quite exist yet, but what will be the dimensions and weight?

s6

I have an iPhone 7 (with a plan) and an iPhone 5c and and old iPhone 4(?). I expect to test with all of them while only having one on a data plan. I also have a Samsung Android, some other smaller Android and a Nexus 7 - all with no plans. I expect them all to be validated. I have been looking into an iPad mini for development and validation (as well as a possible production test environment). .... Maybe the only thing that will have a problem without a plan is if we implemented integrated maps type display...?

I think the production version (except assembled by Adrian) is pictured above next to the pen and quarter...(?). :)
 
At BALLS this year, we did test out part of it by stashing a tracker on the playa out of direct radio range from the flight line. Then when we flew Kevin's rocket, it picked up data packets from the "lost" rocket.

Adrian - I think you should also tell them how the tracking works so well that when you went to retrieve the 'stashed tracker laying in a plastic bag on the playa at BALLS', you managed to actually drive right over it while going to get it... :smile: "priceless!" :smile:
 
I love this idea. How about a loitering blimp/drone instead of waiting for another launch?

I was just saying to my dad a little while ago that I expect to see large balloons with these at launches.

Sent from my HTC6535LVW using Rocketry Forum mobile app

Yup. I'd volunteer to fly a solar powered repeater blimp tethered to my pop up stakes at Airfest next year :)

That sounds like fun, and as far as the electronics go, that should certainly work.

Adrian, this looks simply awesome. Exactly what I would expect from Featherweight and then some.

Thanks; that's very kind of you.


Couple of questions:

To use the apps (either the currently available iPhone one, or the "still-to-come" android one), I'm assuming they will work without a data plan (or cell service), yes? What about using an iPad?

I know the final production version doesn't quite exist yet, but what will be the dimensions and weight?

s6

They will work without a data plan or cell service as long as you can download the app while you're at home, over WiFi. We have been planning to support an iPad and Kevin is looking into how difficult it will be to support the different screen sizes. It would be nice to have at least one large-form factor display, especially for someone like the LCO.

The dimensions (without the antenna) are 1.66 inches by 0.8 inches. The mounting holes are 1" apart horizontally and each is .25" off of the centerline. I haven't gotten around to weighing one yet, but I should be able to do that soon.
 
Adrian - I think you should also tell them how the tracking works so well that when you went to retrieve the 'stashed tracker laying in a plastic bag on the playa at BALLS', you managed to actually drive right over it while going to get it... :smile: "priceless!" :smile:

After we picked up Kevin's rocket I was driving us back to the stashed tracker, in the usual BALLS-with-a-rental-car manner.

"Hey Kevin, are we getting close yet?"
"Huh.... the range is getting larger now... Which side of your tracks did you put the tracker on?"

:facepalm:

I did some dumb stuff that weekend, but driving over my own tracker prototype at 90 mph I think took first prize.

But after I bent the antenna back into shape, the tracker still worked.
 
Forgive me if I missed it reading all these posts....have you mentioned how many channels [if that's the correct term] or units can be used at a launch without interfering with one another. For reference I use the
Telemega and has 10 . The Missile works comes with an assigned freq. that only each user has [over 40,000] I think. Each is serial numbered so more can be added to each persons individual stash. i.e.. you can request several units on your freq.

Is this pertinent to your system or do you use some other method. You seemed to have knocked this out of the ball park...congrats!
Thank you in advance
 
Forgive me if I missed it reading all these posts....have you mentioned how many channels [if that's the correct term] or units can be used at a launch without interfering with one another. For reference I use the
Telemega and has 10 . The Missile works comes with an assigned freq. that only each user has [over 40,000] I think. Each is serial numbered so more can be added to each persons individual stash. i.e.. you can request several units on your freq.

From post #103

For a LoRa receiver to start reacting to a signal, it has to be on the same frequency (out of 50-100 typical channels), with the same selected bandwidth (out of 3 typical choices), and the right spreading factor (out of 7 typical choices) and the same coding rate (out of 4 choices, though most people will probably opt for 1 of the 4 options). So the chances of an unintentional connection are pretty small. Transmissions on a different frequency won't affect the receiver at all, while transmissions that are on the same frequency but don't match up the other three factors just look like noise to the receiver, reducing the receive sensitivity by a few dB during the overlap in transmission.
 
From post #103

For a LoRa receiver to start reacting to a signal, it has to be on the same frequency (out of 50-100 typical channels), with the same selected bandwidth (out of 3 typical choices), and the right spreading factor (out of 7 typical choices) and the same coding rate (out of 4 choices, though most people will probably opt for 1 of the 4 options). So the chances of an unintentional connection are pretty small. Transmissions on a different frequency won't affect the receiver at all, while transmissions that are on the same frequency but don't match up the other three factors just look like noise to the receiver, reducing the receive sensitivity by a few dB during the overlap in transmission.

Thanks Les for finding that! I scrolled back a ways looking for it and then got side tracked by something in one of the posts... :smile:

So if I use the low end of the choices 50 * 3 * 7 * 1 = 1050. or the high end 100 * 3 * 7 * 4 = 8400 possible pairs.

I believe it is our intent to have the units auto adjust their frequency based on units at the field that day (they will communicate between each other on the 'public' channel). I think Adrian will have more thoughts and inputs on that. [Adrian is the expert on the hardware / radio side for sure.]
 
So on the receive end it uses B/T to communicate go the iPhone. How long before an Android app or lacking that can the
raw NMEA strings be streamed to an Android device as is? OS interoperability is something desirable if one would like to run the live data through another terminal app. Kurt
 
So on the receive end it uses B/T to communicate go the iPhone. How long before an Android app or lacking that can the
raw NMEA strings be streamed to an Android device as is? OS interoperability is something desirable if one would like to run the live data through another terminal app. Kurt

I have a little more work to finish the over the air firmware updates (I can update the BlueTooth firmware but need to also handshake with Adrian to update the radio firmware). Once that is done, I switch back to cleaning up the iPhone interface so it has at least the tracking capability at BALLS but with hopefully cleaner screens and BTLE pairing. That would then be 1.0 for iPhone at which point I'll be looking at the Android 'co-version'. I originally was thinking of just separate code for both and I work to develop the iPhone for a feature and then duplicate the effort for Android (not necessarily double since some of the hard part is figured out the first time). There now appear to be some cross platform development environments but I'm not sure if that makes it easier or harder (there is plenty of examples of stuff for iOS and Android but less for the cross platform environment...)

So long story short, I think the iPhone 1.0 will be done in mid December or over the Christmas holidays. My desire is to be starting on the Android version over the Holidays at the latest.

Our goal and highest priority is to have apps across iOS and Android that are fully integrated and customized for the Featherweight Tracker. We want users to be able to get their trackers/GS in the mail, install the app, turn the units on, pair them easily, and be ready to go - without having to figure out what other software needs to be downloaded and chained together...

[I may admire those that can download stuff from various repos and put it all together and it works, but we can't produce a product that uses that model and expect to have any time for future development (we would spend all our time on support trying to explain how to get it working)... ]
 
The short answer might be for Android only users to wait then? I suspect then that that tracker sends more than
just NMEA strings over the link to work with the planned terminal software.
 
Thanks Les for finding that! I scrolled back a ways looking for it and then got side tracked by something in one of the posts... :smile:

So if I use the low end of the choices 50 * 3 * 7 * 1 = 1050. or the high end 100 * 3 * 7 * 4 = 8400 possible pairs.

I believe it is our intent to have the units auto adjust their frequency based on units at the field that day (they will communicate between each other on the 'public' channel). I think Adrian will have more thoughts and inputs on that. [Adrian is the expert on the hardware / radio side for sure.]

Kevin and Les, that's right. We're designing this from the start to support a scenario at a big launch with hundreds of users.

An extra complication I haven't discussed yet is that not all of those combinations are going to be appropriate for a given situation, because two of the factors (spreading factor and bandwidth) also control the data rate and how sensitive the receiver is. The settings that give longer range have a slower data rate, and vice versa. In our case we're going to use an adaptive data rate approach that decides what settings to use for the next packet based on the measured signal strength readings from the previous packet. This way, when someone is turning on and checking their system at the flight line with their units close to each other, fast data rate settings will be used so that each transmission will only take 5%-10% of the available airtime. This will allow several users to share the same channel with the same settings without interfering with each other. Then after launch, as the range goes up the adaptive system will shift toward the longer-range settings. For a flight going to the edge of space, it will take 1-2 seconds for each update.
 
The short answer might be for Android only users to wait then? I suspect then that that tracker sends more than
just NMEA strings over the link to work with the planned terminal software.

Kurt - yes the packets have additional data so aren't actually NMEA strings.

For Android, it is certainly in our best interest to get comparable software for Android as quick as possible... :smile:
 
I have an old iPhone 4s that I want it to work on. Screen is kinda small though. I also have a 5c and 7. 5c seems to be nice tradeoff as far as screen space and small size... I’ll try compiling for older revs until it tells me a feature is not supported...


Sent from my iPhone using Rocketry Forum
 
For those who haven's seen it yet on the website, here's a diagram of the relay function:

BHJ617n.png


Here's how it works:
When the tracker sends GPS data to the ground station, it does it in a cycle. First the tracker sends data to the ground station, then the Ground station sends back an acknowledgement to the tracker, and then there is some time available for listening on other radio channels dedicated for public coordination. During that time, the tracker listens for other trackers and the ground station listens for other ground stations. The trackers are listening on a "lost and found" channel that the trackers transmit on when they are out of contact with their phone and ground station. When a tracker hears from a found rocket, it sends that data back to its own ground station and then to the phone app. When a phone app sees that a new rocket has been found, it tells the ground station to transmit that information during the public coordination period, which allow all the other ground stations in range to get the same information.

This might sound complicated, but it will all be happening in the background so if your rocket lands behind a hill, you'll just see a new updated location of your rocket as soon as another rocket carrying a Featherweight tracker launches into a clear line of sight to the your rocket.

A caveat here is that the code isn't done yet, though I have been planning for this since I started about 10 months ago. At BALLS this year, we did test out part of it by stashing a tracker on the playa out of direct radio range from the flight line. Then when we flew Kevin's rocket, it picked up data packets from the "lost" rocket.

After seeing this, I’m imagining people losing a rocket in the corn, then sending more rockets up over the corn to find the first one...

“There was an old lady who swallowed a fly...”
[emoji12]


Sent from my iPhone using Tapatalk Pro
 
After seeing this, I&#8217;m imagining people losing a rocket in the corn, then sending more rockets up over the corn to find the first one...

I'm imagining someone writing some code to relay the data stream to a drone and have it home in on it.
 

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