the Fluctus flight computer

[darrenf]

Looks like everything worked, just backwards. Maybe just a simple wiring issue.

Having the option to be able to assign outputs to events does mean you have twice as many opportunities to flip things around by accident.

The Fluctus never fired the main. I’m looking at the logs in the EggTimer which did fire both channels to see if that was backwards somehow. Just haven’t had a chance to dig through it all yet. I’ll get to it this weekend and report back. Could just be that the nose cone came off under g forces.

 

[darrenf]

@Ulyu Do you know if there is any danger of the Fluctus being interfered with or interfering with any of the other trackers currently on the market, like the Egg Timer series, etc? At a big launch, such as LDRS coming up multiple devices on the same frequency could pose a problem.

 

[kjhambrick]

@darrenf --

Nice Flite !

Do you mind sharing your raw data files here on TRF ?

Thanks !

-- kjh

 

[Rocket_Col]

So, I flew the Fluctus today. It worked like a champ. Of course I entered the main deployment altitude thinking in feet but as we all know it was meters. Fortunately there wasn't much wind and it didn't drift far from the main coming out at 400 meters instead of 400 feet. Big issue is I couldn't see my computer screen at all even though the skies were overcast. When the iOS app comes out it will be very helpful at the launch site.

Edit to add... After some forensics today, the Fluctus never fired the main chute, because it was set to 200 meters (I did remember while setting it that it was in meters, just in the heat of the moment of the flight I forgot that I set it correctly) AND the vertical velocity was greater than 40 meters per second, which since it was already under main it was falling at 3.5 meters per second. I changed the AND statement to an OR statement as it should have been in the first place. My mistake there. Hoping to fly it again this coming Sunday.

Looks like the nose was knocked off. Did you use shear pins?

 

[Ulyu]

Here is my flight from this past Saturday in my rebuilt Andromeda now known as WhistlePig. First flight with the Fluctus. Haven't figured out for sure why the main came out early yet. It was not a malfunction of the Fluctus, that much I know for sure.

Nice flight ! Too bad you got the logic operator wrong.
By the way, in case you missed that, the latest version you're using already has presets and details built right into the software, including the same dual deploy events you did. It's available via the drop down menu at the bottom left of the configuration tab.

Do you know if there is any danger of the Fluctus being interfered with or interfering with any of the other trackers currently on the market, like the Egg Timer series, etc? At a big launch, such as LDRS coming up multiple devices on the same frequency could pose a problem.

Like on any system that uses radios, there could probably be conflicts, yes, but I don't know the details of the frequencies and modulation that eggtimer uses, so I can't predict what might happen. (In the worst case it will just jams the telemetry, so there's no real “danger”...)
The best thing to do is to prepare for this eventuality and change the radio channel if this kind of problem occurs (incidentally, it's got me thinking that I should add the ability to switch radio channels in the mobile app... it might be handy to be able to do this without taking out a laptop).

 

[ksaves2]

@Ulyu Do you know if there is any danger of the Fluctus being interfered with or interfering with any of the other trackers currently on the market, like the Egg Timer series, etc? At a big launch, such as LDRS coming up multiple devices on the same frequency could pose a problem.

ONLY fly compatible trackers and deployment electronics PERIOD. Ground test before flight. Sure have a friend who's flown the same EXACT installation you have, might be able to forego a ground test. To ground test, put contained ematches sans 4f on the deployment channels. Set rocket upright turn on the altimeter(s). Turn on the trackers and let the whole thing sit for 45 minutes to an hour. Listen closely when turning on the deployment devices during the test to see if you hear them reset/recycle. Do that into a flight and it will be a lawn dart. Sometimes the deployment electronics will blow the channels/chute(s) on the pad (if lucky) or blow on ascent where a cardboard rocket will be a zipper. Sometimes the deployment channels will lock out and not function when they should.
I've witnessed many failures from first time Rf tracking fliers who didn't do a full up ground test (sans 4f of course) and lose their rocket and much of their
hardware due to damage.
If flying a combo GPS tracker/deployment altimeter on the same board, one can be comfortable that the maker got all the Rf bugs out of the system before selling it on the open market. It's separate components one needs to be concerned about and fully ground test before a new, first time launch attempt.

 

[darrenf]

ONLY fly compatible trackers and deployment electronics PERIOD. Ground test before flight. Sure have a friend who's flown the same EXACT installation you have, might be able to forego a ground test. To ground test, put contained ematches sans 4f on the deployment channels. Set rocket upright turn on the altimeter(s). Turn on the trackers and let the whole thing sit for 45 minutes to an hour. Listen closely when turning on the deployment devices during the test to see if you hear them reset/recycle. Do that into a flight and it will be a lawn dart. Sometimes the deployment electronics will blow the channels/chute(s) on the pad (if lucky) or blow on ascent where a cardboard rocket will be a zipper. Sometimes the deployment channels will lock out and not function when they should.
I've witnessed many failures from first time Rf tracking fliers who didn't do a full up ground test (sans 4f of course) and lose their rocket and much of their
hardware due to damage.
If flying a combo GPS tracker/deployment altimeter on the same board, one can be comfortable that the maker got all the Rf bugs out of the system before selling it on the open market. It's separate components one needs to be concerned about and fully ground test before a new, first time launch attempt.

I think you are confused as to what I am talking about. I'm talking about a large event where many devices in many different rockets will be powered on at the same time.

 

[darrenf]

@darrenf --

Nice Flite !

Do you mind sharing your raw data files here on TRF ?

Thanks !

-- kjh

Not at all. Once I get the Eggtimer info pulled I'll post them both.

 

[ksaves2]

I think you are confused as to what I am talking about. I'm talking about a large event where many devices in many different rockets will be powered on at the same time.

No, I'm not confused at all. Power up two trackers on the same frequency unless they are of an advanced type that can pipe multiple positions on the same channel and that frequency will be toast. I just want to get into the prospect of flying discrete components. Sure if a maker/manufacturer is flying several devices on the same board they're selling, they'll be danged sure to be certain all the components play well together for the device they are advertising. "The greatest multi-deploy altimeter, GPS tracker and in flight computer ever INVENTED (sic) on one board. If that goes bad, unsuspecting fliers that get dissed and could kill a new start company that muffs up.
The issue is mixing different Rf trackers including home made with deployment devices. Start doing that without ground testing and may be visiting "lawn dart" territory.
At a "large launch" it's important to have a frequency board like R/C guys started back in the 50's thereon to avoid conflicts for telemetry and control. Makes life a misery if one wants to fly and finds out someone else is "on frequency" and "IT'S" a beech to take down their rocket to change tracking or control frequency.
There may be digital trackers out there now that can operate on the same frequency discretely without interference but they came after my "prime time" of flying. Kurt

 

[OzHybrid]

1. That's a good idea... I'll make the software remembers the selected channel every time it reopens, thank you.
   
   
2. Thats also a good idea, it's already something I've been asked to do, and it will be done. It'll just take a bit of time because I need to set up all a warning and rule verification system, but it'll happen for sure.
   To go into more detail, the way it will be implemented is that a warning will be displayed in the control center if Fluctus detects continuity on a pyro output, but no rule was configured for this same output.
   
   
3. Yes, you can now switch the telemetry display and speaker to imperial in the new software version. It's coming soon !
   (however, note that the configuration will still have to be performed in international metric units)
   
   
4. No, that's not planned, but if I remember correctly Google Maps works even without an internet connection (it just need some GPS satellites in view).
   So by scanning the QRCode generated in the Fluctus Control Center, your smartphone will be able to guide you to the rocket even if no map is downloaded.

Google Maps(GM) will work without the internet IF you have downloaded the map to your phone beforehand.
Open GM, log into them with your Google account(if not already logged in), click on your login logo at top right, Offline Maps is 5th option down. Select it. Select area of map you want to download. Wait........ done.

 

[ksaves2]

Google Maps(GM) will work without the internet IF you have downloaded the map to your phone beforehand.
Open GM, log into them with your Google account(if not already logged in), click on your login logo at top right, Offline Maps is 5th option down. Select it. Select area of map you want to download. Wait........ done.

Sheeeooooot!!! I did that years ago when I still could only get slow DSL at home and there was fiber optics at work. I'd go there on the weekends when
no one was working and bandwidth was low. I'd download photomaps to GPS rocket tracker at varying resolutions for use on the launchsite and didn't have
an internet connection. Many of my Ham APRS tracking programs would allow that too so I'd be downloading with multiple devices at once.

Was nice to see if one avoided a barn, tree, lake or stream or see that they have to cross over that "road to the south" to get into that next cornfield to recover the rocket. There was nothing like a photomap then and still nothing like them now.

 

[SolarYellow]

At a "large launch" it's important to have a frequency board like R/C guys started back in the 50's thereon to avoid conflicts for telemetry and control. Makes life a misery if one wants to fly and finds out someone else is "on frequency" and "IT'S" a beech to take down their rocket to change tracking or control frequency.

I'm pretty sure that if you have the complete interface device, Eggfinder products can be reprogrammed to operate on any of the available frequencies by the user, even at the field. So a frequency board would be a great idea.

 

[ksaves2]

I'm pretty sure that if you have the complete interface device, Eggfinder products can be reprogrammed to operate on any of the available frequencies by the user, even at the field. So a frequency board would be a great idea.

Well sure........... But if one has to break into a loaded rocket to get access to the Eggfinder "product" to CHANGE the frequency on the tracker AND the receive station it makes it a good idea to post what frequency one is interested in flying with BEFORE THEY GET TO THE MAJOR LAUNCH! Only for coordination mind you so one avoids a tedious "reprogramming". Yeah it can be tedious breaking into a prepped rocket if you don't know already!
If there's some frequency control before hand then folks can pre-plan their tracker frequencies to avoid conflicts or at least coordinate when their tracker will be on and off air. I had to change an E.F. frequency one time on site and it was a MAJOR PITA!!!!! I can't emphasize that enough! One big PITA to do an onsite frequency change plus I had to have the damned laptop to do it! I couldn't track down the person who was on the same frequency I was on to find out the particulars either.
Makes me want to only attend invitation only launches like in the days of old. At least being a Ham I knew my Ham trackers wouldn't interfere or be interfered by the "unlicensed" E.F. stuff of which I own several 900Mhz units too. Cerving as I recall does Ham stuff too on request now unless he stopped it.
Not as many Ham radio/rocket fliers back then (and no unlicensed stuff) though I did help a Ham/rocket flier find his Big Red Bee APRS/GPS tracker. Had a Kenwood D7Ag handi talkie ham radio interfaced to a Garmin 60Cs(Csx) handheld mapping GPS with a serial cable. The poor fellow had the lat/long units set wrong in his Garmin mapping GPS to track. I saw he was in distress and couldn't find his rocket with positions coming in. I looked at his receive station Garmin GPS, saw the units were wrong and fixed it in the setup. We both walked out to the rocket as it was in receiving range and transmitting a good position.
To see the happiness on a fellow flier's face when they thought their pricey project was lost and I did some simple manipulations to find the rocket intact is to use the cliche' is "priceless". Probably the only time that would happen to me to see a fellow flier recovering a rocket they thought was totally lost.
Yeah, I did tell him what I had to do on his Garmin GPS to get it to indicate the rocket's position. I think it had something to do with using decimal lat/long positions as opposed to degrees, minute, seconds units as the Garmins came with pre-loaded. Easily changed in the setup screens.
I found that out with ground testing of my units early on long before this flight occurrred. The positions made no sense so I read the Garmin manuals more. Thank heavens the Garmins had the capability to change the lat/long units to whatever the enduser needs!
I had a GPS map in hand when folks thought that Rf tracking with Yagi's and pricey attenuators were the cat's meow.
A Kenwood D72A with an interface cable to an ancient handheld Garmin 60 Cx or Garmin 60Csx mapping GPS is still a killer mapping rocket field tracker that can be read in sunlight mind you. Sure there's stuff on one's phones now but I can't read mine in the sun as well as I can my ole' Garmins I take out with me hiking every time. Keeps my hiking distance honest. Plus works with rockets AND THE BATTERIES ARE REPLACEABLE!!! Unlike a lot of stuff now!

 

[cerving]

FYI, the Eggtimer Quasar can be frequency-programmed through the WiFi interface, without a physical connection. That's one of it's nicer features.

 

[pbahorich]

I ran a radio range test the other day. The Fluctus was mounted inside a 38mm fiberglass AvBay coupler. I had a #8 stainless allthread immediately behind it, parallel to the antenna with maybe a 1mm gap between the allthread and Fluctus antenna at the antenna's widest point. I had the transmitter mounted on a fencepost atop a hill. I was 6.1 miles (9.8 km) away with the Steady ground station on another hill (essentially unobstructed view) and was able to communicate with the Fluctus. SN ratio indicated on Steady was about 2 dB. I would not have any qualms about sending Fluctus to 50k feet altitude.

 

[Voyager1]

I ran a radio range test the other day. The Fluctus was mounted inside a 38mm fiberglass AvBay coupler. I had a #8 stainless allthread immediately behind it, parallel to the antenna with maybe a 1mm gap between the allthread and Fluctus antenna at the antenna's widest point. I had the transmitter mounted on a fencepost atop a hill. I was 6.1 miles (9.8 km) away with the Steady ground station on another hill (essentially unobstructed view) and was able to communicate with the Fluctus. SN ratio indicated on Steady was about 2 dB. I would not have any qualms about sending Fluctus to 50k feet altitude.

Impressive result! However, I’d be even more impressed if you conducted this test over flat, or even better, rough terrain and achieved similar results without the advantages of elevation and line of sight. That would be a more realistic scenario.

 

[pbahorich]

Impressive result! However, I’d be even more impressed if you conducted this test over flat, or even better, rough terrain and achieved similar results without the advantages of elevation and line of sight. That would be a more realistic scenario.

I was very intentional in my test. I was interested in determining the max altitude I would feel safe with.

It is impossible for a 900 MHz system to achieve similar results over rough or even flat terrain, since they are essentially line of sight.

The way GPS rocket trackers work is that the receiver stores the last position received (immediately before landing) and guides you to that after landing. So having a great range on the ground is not important. It just needs to be good enough for the last few feet as you walk up to the rocket. I usually get a visual before the receiver re-acquires anyway. So long distance (miles) range in rough or even flat terrain is not a realistic scenario.

 

[carfixer1]

I hope mine shows up in time for Airfest!

 

[darrenf]

Here is my flight from this past Saturday in my rebuilt Andromeda now known as WhistlePig. First flight with the Fluctus. Haven't figured out for sure why the main came out early yet. It was not a malfunction of the Fluctus, that much I know for sure.

Video courtesy @jnmiller

So, after closely looking at this video it's clear the violence of the drogue ejection caused the nosecone to pop off when the shock cord went taught. I'm going to extend the drogue cord and wrap a little tape around the neck of the nosecone to give it a bit more friction. It will be flying next week at LDRS and I'll report back.

 

[cerving]

So, after closely looking at this video it's clear the violence of the drogue ejection caused the nosecone to pop off when the shock cord went taught. I'm going to extend the drogue cord and wrap a little tape around the neck of the nosecone to give it a bit more friction. It will be flying next week at LDRS and I'll report back.

A smaller drogue charge may be in order too... I have a tendency to do the same, about half of the time my nose cones pop off, even with shear pins.

 

[SolarYellow]

Does that not show up in ground testing?

 

[cerving]

Does that not show up in ground testing?

Not always. If you have the nose cone pinned during drogue testing, sometimes it will hit the ground and the nose cone won't pop off.

 

[darrenf]

Not always. If you have the nose cone pinned during drogue testing, sometimes it will hit the ground and the nose cone won't pop off.

Even without anything to keep the nose cone in place it did not come off in ground testing for me.

 

[Ulyu]

Yes, the actual ground station has no Bluetooth connectivity, so the only way to connect it to a phone is via an OTG cable.

I'm planning to make a much more compact, battery-powered and bluetooth-capable version of the ground station.
This will make the Fluctus mobile experience much better, and it's also related to another gps tracker project I have in mind.
(keep in mind that I haven't started developing this thing yet, so don't expect it anytime soon...)

Here it is, a first (very) rough prototype of the Steady Bluetooth ground station:

The new wireless firmware and app are already 100% working though, both on Android and iPhone.

I just need to redesign a suitable hardware.

 

[darrenf]

Here it is, a first (very) rough prototype of the Steady Bluetooth ground station:

The new wireless firmware and app are already 100% working though, both on Android and iPhone.

I just need to redesign a suitable hardware.

I will definitely be ordering this as soon as possible. I love the speed of your development.

 

[jgarbus]

Ulyu,

Could you add an additional feature to the "Directly go to flight mode" setting? Could you add an addition feature that if checked, it has to wait for GPS lock prior to arming?

Also, I noticed that the flight clock is running while in wait launch when using the "direct to flight mode". Shouldnt this clock wait until launch detection to start?

 

[Ulyu]

Could you add an additional feature to the "Directly go to flight mode" setting? Could you add an addition feature that if checked, it has to wait for GPS lock prior to arming?

I can do that, yes, but I don't really see the use case for this feature, why would you want something like that ?
I find it almost dangerous to arm only when the gps is locked, because then it means you have no idea whether fluctus is armed or not when you launch the rocket (unless you check it remotely via telemetry, but then what would be the point of automatic arming ?).

Also, I noticed that the flight clock is running while in wait launch when using the "direct to flight mode". Shouldnt this clock wait until launch detection to start?

Yeah that might be counterintuitive. In reality, the T 0 is indeed at launch when you look at the black box data, but it's not the same value that's displayed in the telemetry interface.
I'm going to check if I can lock the timer at T 0 while waiting for the launch detection without breaking anything, and if it's good I'll implement that in the next update.

 

[jgarbus]

I can do that, yes, but I don't really see the use case for this feature, why would you want something like that ?
I find it almost dangerous to arm only when the gps is locked, because then it means you have no idea whether fluctus is armed or not when you launch the rocket (unless you check it remotely via telemetry, but then what would be the point of automatic arming ?).



Yeah that might be counterintuitive. In reality, the T 0 is indeed at launch when you look at the black box data, but it's not the same value that's displayed in the telemetry interface.
I'm going to check if I can lock the timer at T 0 while waiting for the launch detection without breaking anything, and if it's good I'll implement that in the next update.

Specific the the GPS lock, I have been leaving the laptop and base back at Launch control and taking my project out to the pad, set it up and arm it. It would be nice to know if the GPS is locked prior to leaving the pad. So maybe it isn't waiting for lock to arm but maybe changing the blink rate of the LED or something. Just nice to know everything is fully ready before walking away from the pad.

 

[pbahorich]

I am really looking forward to trying out the BT version and ground station!

On the BT version of Steady, I suggest means to prevent the antenna from breaking off when it is carried in a pocket for the 2km trek out to rocket in the desert and back. This is a typical Saturday launch day for me. I definitely get more than my 10,000 steps on these days...
Here is one idea:
Mount the antenna on the side (like Featherweight). You could use a kickstand type device to keep Steady on its edge when it is sitting on the prep table, if that is even necessary.

 

[Ulyu]

Specific the the GPS lock, I have been leaving the laptop and base back at Launch control and taking my project out to the pad, set it up and arm it. It would be nice to know if the GPS is locked prior to leaving the pad. So maybe it isn't waiting for lock to arm but maybe changing the blink rate of the LED or something. Just nice to know everything is fully ready before walking away from the pad.

Ok I understand, what I will do is add a beep with a recognizable tone if the gps is locked while it's waiting for launch detection.