The Eggtimer Quasar - A WiFi-enabled GPS/Altimeter

[cerving]

Eggtimer Rocketry is proud to introduce the Eggtimer Quasar, the replacement for the discontinued Eggtimer TRS.

On the altimeter side, it has 3 outputs: Drogue, Main, and a configurable AUX output that can act as an airstart timer or a backup Drogue or Main. Like the Eggtimer Quantum and Proton, it's WiFi enabled... all functions are remotely configured via a WiFi/browser interface (no Internet or apps needed): changing settings, arming/disarming, downloading flight data, and performing deployment tests.

On the telemetry side, it sends out GPS and altimeter telemetry (altitude, deployment status) once per second. It uses the same tried-and-true Eggfinder LCD receiver, with no firmware updates required to display the data (your LCD receiver "thinks" it's a TRS and displays the data accordingly). What it doesn't have is that annoying "pairing" process... it sends out GPS data almost as soon as your turn it on, so your LCD receiver can be set to TX/Mini device mode and skip the pairing screen. No more trying to get the timing just right to arm with your LCD receiver either... that's now done with your phone and the browser interface. It will be available in the license-free 900 MHz band, the EU/UK 869 MHz band, and the 70cm Ham band.

It's about 5 1/2" long, and can fit comfortably into a 29mm motor mount tube (yes, we've done it... the challenge is finding a battery that fits!). That was one of the issues with the TRS... it was pretty big and didn't fit well into a lot of rockets. See the picture below for a comparison picture.

The Eggtimer Quasar lists for $100, that's the same price as the TRS with the external antenna, but you're getting a lot more functionality for your money. We expect to be shipping them around the end of November... conveniently in time for the Eggtimer Holiday Sale, and yes, it will be discounted along with everything else. (Keep an eye out for the sale details...)

As usual, thanks for your continued support!

Cris Erving, Eggtimer Rocketry

 

[markg]

Very nice! Love the 3rd channel.

cheers - mark

 

[Worsaer]

Looks great Cris. I’m noticing the type of antenna. Will it support an SMA connector if desired?

 

[cerving]

The Quasar uses the same screw-on stubby antenna that the Eggfinder Mini uses, it will not directly accept an RP-SMA connector. We've tested prototypes with both types of antennas, and the stubby antenna works at least as well... it should, it's spec'ed at 2.4 dBi gain with a SWR of 1.2 at the center frequency. You probably wouldn't do any better with an external antenna, especially if you have to add a cable to it. The Quasar's PC board ground plane is much larger than an Eggfinder Mini, so the antenna works much better with it than it does with the Mini, and that includes being inside an AV bay with allthreads and other stuff (where it's most likely to end up in most builds). We've comparison-tested it in AV bays up to 12,000', and did not have any issues with the signal vs. putting it in a nose cone without as much junk in it.

 

[Hobie1dog]

 

[Kallahan11]

So you literally just sent out my invoice and then post this?

 

[cerving]

So you literally just sent out my invoice and then post this?

We can create more invoices... we have the tools and the talent.

 

[bad_idea]

Well this just radically changed the direction of the design I've been working on for a future build. Very exciting!

Do you have a rough figure for the assembled mass?

 

[cerving]

It's about 28 grams.

 

[bad_idea]

It's about 28 grams.

Fantastic. Thank you!

 

[ke8nai]

What’s the altitude limit on GPS? And can you receive multiple on a single ground station?

 

[NateB]

That looks great, and I think I have one of the last TRS you sent out. Does it still have the choice for separate batteries to isolate power to the deployment channels?

 

[Worsaer]

Cris, when possible, can you please also post a photo of the 70cm version, assuming the antenna is a bit different?

 

[n3tjm]

I need to update my Secret Santa Wish List . Note: If someone orders me one of these and the receiver for Secret Santa, here is the proof of my license

 

[Scott_650]

Cris - what difficulty level does the new Quasar rate?

 

[markg]

What’s the altitude limit on GPS? And can you receive multiple on a single ground station?

Ground station can only receive one at a time. I mounted 2 x ground station that share a GPS module into a single case to track multiple receivers for my two stage projects.

 

[cerving]

Answers to your questions...

1) The standard COCOM altitude limit is 18 km, with a 515 m/s and 4G accel limit. That's why you lose GPS data at boost... pretty much the same with all non-military GPS's. The GPS has a "balloon mode" that will go up to 80 km, with reduced accel/velocity limits... we intend to make that a settings option at some point in the future, you'll be trading off increased altitude limit for reduced sampling rate (like once maybe every 5 or 10 seconds instead of 20x/second.)

2) Like all Eggtimer products, you need a separate receiver for each transmitter. However, like the TRS, the GPS and altimeter telemetry are integrated so you only need a single receiver for both types of data. We intend to expand the telemetry that you can get out of a Quasar... real-time apogee comes to mind (you don't get that on a TRS). That will require some LCD firmware changes, our goal in the initial release was to replicate what the TRS did since the TRS is now EOL, so we didn't want to have to make you update the LCD firmware too.

3) The 70cm version looks identical... the antenna is the same form factor, except with a different color stripe (it's red instead of yellow). Ditto for the 869 MHz EU/UK version... the stripe is teal.

4) We're calling the build a 5 out of 5, based on our Focus Group. The build is similar to a Proton. All the itsy bitsy parts are on the bottom side.

 

[MrEd]

I think I could build a rocket around this. Sign me up!

Great job Cris!

 

[WoShuGui]

Cris,
This looks awesome. Is there a way to have set a separate deployment switch/battery like TRS?

 

[cerving]

Cris,
This looks awesome. Is there a way to have set a separate deployment switch/battery like TRS?

The Quasar is designed for a single 2S Lipo battery, it does not have a separate battery input for deployments. Due to the dual-switched architecture (like the Quantum and Proton) it really doesn't need it. BOTH sides of your outputs are isolated from the battery, there is no direct "common" connection between your ematches and the battery like there are with "other" altimeters. Essentially, there is a WiFi Switch on the deployment power, and it's not turned on until you arm the Quasar AND a launch has been detected AND the first output event occurs. If you really want to add a mechanical switch, you can put it on the battery, once you turn on power the Quasar starts transmitting GPS coordinates almost immediately (unlike the TRS, which required that you were armed for flight before it sent out GPS data). This has in-flight recovery implications too... if your battery connection comes loose and the Quasar resets, it will still send out your GPS location data.

 

[heada]

Will it support other battery configurations? 3S, 4S? I have a few 4S 1300mAh 120C batteries that I use for other devices in single battery mode and I'd like to standardize on a single battery for larger av-bay configurations.

 

[cerving]

No on the 4S. You CAN use a 3S, but there's generally no advantage to using one, all it does is to get the regulator hotter. If you are trying to use a solenoid release or hotwire as a cable cutter that might be a good application, but for a standard pyro deployment a 2S is more than adequate. BTW, that goes for all of our altimeters (except the ION/Apogee)... a 2S Lipo is the preferred power source. I'm not aware of anybody that specifies a 3S or 4S, and I know of a few that would fry instantly if you tried to use them with one.

 

[jhill9693]

Sweet! I look forward to getting mine.

Any chance you could do an even smaller one without the deployment channels? I’d love an Ion with GPS (or the equivalent).

 

[cerving]

It wouldn't be that much smaller or cheaper, so it's not really worth doing. I have a board from over a year ago that was originally supposed to be just that, but I never wrote the firmware for it.

 

[GrouchoDuke]

Dude, nice. Congrats on the new product!

 

[heada]

No on the 4S. You CAN use a 3S, but there's generally no advantage to using one, all it does is to get the regulator hotter. If you are trying to use a solenoid release or hotwire as a cable cutter that might be a good application, but for a standard pyro deployment a 2S is more than adequate. BTW, that goes for all of our altimeters (except the ION/Apogee)... a 2S Lipo is the preferred power source. I'm not aware of anybody that specifies a 3S or 4S, and I know of a few that would fry instantly if you tried to use them with one.

I had hoped it'd support 4S as the TRS v2.07 user guide spec'd 4.5v to 30v and yes, the 4S I use powers a solenoid.

I use 2S 450mAh 50C on my Quantums so I can use them for this as well. Looking forward to putting in an order when released.

 

[jhill9693]

It wouldn't be that much smaller or cheaper, so it's not really worth doing. I have a board from over a year ago that was originally supposed to be just that, but I never wrote the firmware for it.

Thanks. If I wanted to share a battery between an actual Ion and Mini, could I do that? If so, are there any special considerations?

 

[cerving]

Thanks. If I wanted to share a battery between an actual Ion and Mini, could I do that? If so, are there any special considerations?

Slight hijack, but if you have Mini C3 (the one with the pre-mounted GPS) it supports a 1S Lipo, so you could use the same 1S battery for both of them. I did it when I was testing the Mini, with the 350 mAH battery that we sell for the ION.

 

[MikeT]

Holiday Sale I can't wait.

 

[RockeTiltometer]

Cris - well done...Frank