Eggtimer Quasar FAQ’s

What does the Eggtimer Quasar do?

The Quasar is a combination 3-output recording altimeter and GPS tracker.   For many rockets, it’s the only electronics that you’ll need to recover your rocket… it handles deploying the parachutes and tracking your rocket so you can easily retrieve it after landing.

How does the Quasar help you find your rocket?

When in flight, the Quasar constantly sends out the GPS location of your rocket to an Eggfinder LCD receiver on the ground.   When your rocket lands, you use the “last received data” from your LCD receiver to locate your rocket… either directly from the LCD receiver, or using a navigation app on your phone.   You basically tell it to “take me there”, and follow the navigation instructions.

What is required for a complete Quasar GPS tracking package?

At a minimum you’ll need a Quasar and an Eggfinder LCD receiver.  The LCD receiver has a 2-line display that gives you the GPS coordinates of your Quasar, among other things.   Typically, you would take the GPS coordinates and plug them into a navigation app on your phone, and tell it to “take me there”… that would lead you to your rocket.   We also offer some options for the LCD receiver.   We recommend getting the LCD-GPS Module, which adds navigation capability to your LCD receiver; it will do the “go there” navigation for you without having to use your phone.   We also have a Voice Module that will allow your LCD receiver to speak the current altitude during flight, deployment events, and when used with the LCD-GPS Module it can speak your distance and bearing to the rocket.   Very handy for those long drive-out recoveries… you don’t have to keep looking at the display.

Do I need a Ham license to use it?

The Quasar (and the LCD receiver) are offered in region-specific license-free bands for North America, Australia/New Zealand, and EU/UK.   We also offer a 70 cm version that requires a Ham license.   The advantage of the Ham version is that you’ll get about twice the range in open air, and there are a lot more channels to choose from (300!).

What is the range for GPS/telemetry?

The 900 MHz version of the Quasar should be good for at least 20,000′ of range when installed in a typical AV bay, and probably over 30,000′ when installed in a nose cone with no metal interfering with the signal.   You can expect about twice that if you’re using the 70 cm Ham version.   That’s a straight line-of-sight range… obviously any obstructions will reduce that range.

Will putting the Quasar in an AV bay with metal allthreads reduce the range?

Putting an Quasar in an AV  bay with steel allthreads definitely has an effect on the range… the question is, How much?   That’s hard to say… however, in our tests with 54mm, 3″, and 4″ fiberglass rockets we did not see a significant degradation of the signal up to the limit of the motors we had with our test rockets (14,000′ with a 75mm 5-grain M).   For most users, with a typical launch site waiver of under 20,000′, we don’t think you’ll see any issues.   It would be better, of course, to put it in the nose cone with no metal around the antenna… however, you’d have to make allowances for the deployment charge wires and the like, so you may not want to do that.

Besides the GPS coordinates, what other telemetry data does the Quasar transmit?

With the current (1.01a) firmware, the Quasar sends out real-time altitude, deployment channel status, and on landing it sends out the apogee.   Future firmware updates will transmit real-time velocity and maximum velocity.   Real-time velocity is mainly useful on the way down (you’re not going to be looking at the display on  the way up!), to help you get an idea of how fast it’s coming down.   You can get that, of course, by looking at the change in the real-time altitude call-out, but it’s nice to have it tell you that without having to figure it out.

What is the advantage of the Quasar’s WiFi interface over “other” altimeters?

The WiFi interface provides an easy way of remotely configuring, arming/disarming, downloading data, and deployment testing.   Nothing other than your phone (or tablet) is required… it uses the WiFi built into your remote device, along with its browser.   “Other” altimeters may require a special cable or display that must be connected directly to the altimeter to make changes or download data; that makes it difficult to make changes out in the field (for example, changing your Main deployment altitude from 700′ to 500′ because of higher than expected winds).   A lot of people with those altimeters just leave them at the factory defaults because of the hassle… with the Quasar, it’s a snap… just click on the Change link from the main screen and make the change.   You can even do it at the pad, right before arming for flight.

Do I need to have Internet at my launch site to use the Quasar?

No.   The WiFi interface is a connection directly between your phone and the Quasar… the Internet is not involved in it.   You DO use the same WiFi manager and browser on your phone that you would use for Web pages, but it’s not on the Internet.

Do I need to load any apps on my phone to use the Quasar?

Not for the Quasar’s altimeter functions.  The Quasar uses the existing WiFI manager and browser on your phone.   

If you are using the “vanilla” LCD receiver without the LCD-GPS Module, you’ll probably need to get a navigation app to track your rocket… there are a lot of them out there, you just need one that you can enter GPS coordinates into so you can tell it to “take me there”.   If you have the LCD-GPS Module in your LCD receiver, you don’t need any apps at all… the LCD receiver will provide that functionality.

What output settings are available?

Drogue:  0-3 secs from nose-over by 0.1 sec, 3-30 secs by 1 sec.; pulse width from 1 to 9 seconds or continuous.

Main:  AGL 100-500′ by 50′, 500′-3000′ by 100′; pulse width from 1 to 9 seconds or continuous.

AUX:  Drogue and Main modes: Same as above; Airstart mode: Delay from launch detect of 0.3 to 30 seconds, with optional altitude@time and velocity@time qualifiers.

What if I don’t want to use one of the outputs?

Easy, you can turn any or all of them off from the deployment settings… just set it to OFF.

How does remote arming work?   I’m used to using a switch to turn on my altimeters…

By default, the Quasar won’t arm for flight until you explicitly arm it remotely, that’s done by entering a 4-digit code into a verification box and submitting the page.   The code changes every 60 seconds, and also every time you refresh the page.   This prevents you from “pocket arming” your Quasar.    In order to arm the Quasar, all enabled outputs must have continuity… it won’t allow you to arm if you don’t, and the page will show you which one is the problem.   Remote arming is safer than arming with a switch, particularly for rockets with airstart motors; you don’t have to stick your face next to the rocket and fiddle with some switch while it’s on the pad.   

In addition, the Quasar (like the Quantum and Proton) have “dual-switched” outputs… the outputs are essentially “dead” until you arm the Quasar AND a launch has been detected AND the first triggering event occurs.  Unlike most other altimeters, there is no direct connection between the battery and an igniter; both sides of your igniter are isolated from the battery.

How do I perform remote deployment testing?

Remote deployment testing is easy… you simply connect to your Quasar and go to a special test page.   You select the output that you want to test, enter the validation code (just like arming for flight), and it will count down from 5 and fire your charge.   You can do this from at  least 100′ away if you wish… ideal for large rockets with several grams of pyro powder in the charge wells.   It’s much safer and easier than running a wire outside your AV bay and touching the leads to a battery.

Will it trigger a hobby servo for non-pyro deployments?

Yes, any or all of the three outputs can be configured to trigger a servo during deployment events (i.e. on the way down).   It can be used with “trapdoor” or similar mechanisms for non-pyro recovery.  There’s a special header for servos on the board, we recommend that you use a separate battery to power and servos, along with a few external components (some resistors for signal isolation and capacitors on the servo power for filtering)… it’s in the User’s Guide.

Can it be used to fire a second-stage motor?

Yes.   It acts as a timer, from when launch is detected.   For safety, you can optionally set some criteria for triggering… altitude@time, and velocity@time.  In order for the airstart to occur, you must have reached the minimum altitude and/or velocity at the time of triggering.   If either of the selected safeties doesn’t occur, the motor won’t be triggered and the channel will be disabled.

What data does it collect?

The Quasar collects real-time altitude, velocity, and “milestone” events (i.e. launch detect, deployments).   This is pretty typical of recording altimeters.   By default, on the way up it samples at 20 times per second and on the way down it sample as 2 times per second.    These rates are configurable in the Settings screen.   The Quasar saves your last 14 flights, on a rotating basis.   There are also pads to connect an OpenLog datalogger to capture the GPS/telemetry data, which can be imported into Google Earth or similar programs after the flight.

How do I view the data after the flight?

After landing, a summary page of your flight is immediately available from the WiFi interface… once you retrieve your rocket, you simply connect to the Quasar with your phone’s WiFi/browser, and you’ll see it.   You get apogee, maximum velocity, average acceleration at maximum velocity, deployment events, etc., along with the time-of-flight that they occurred.   After you get back to your worktable and reset the power, you can download detailed .CSV-formatted data which can easily be imported into Excel or other data analysis programs to give you nice pretty graphs.   

How big is it?

The Quasar is about 140mm (5.5″) long, 27.7 mm wide (1.09″) and 12.5mm (0.5″) tall.   It weighs about 28 grams (1 oz).   It will fit comfortably into a 29mm motor mount tube with a 1/8″ sled… which is the standard nose-cone tracker mount for a lot of the rockets that we use for testing.   You may find that the hardest part is finding a battery to fit… with a 38mm or larger tube, that’s really not much of a problem, you can easily get a 2S Lipo in the 500-800 mAH capacity range into that tube.

What batteries does it require?

The Quasar requires a 2S/7.4V LiPo battery, we recommend using one rated 500 mAH or more.   It draws between 100 mA and 250 mA while operating, depending on what it’s doing; flight after launch requires the most power because it’s constantly transmitting data, but once it lands that power goes way down because the transmissions occur less frequently.

What is the output current limit?

The outputs on the Quasar use special automotive-type drivers, current-limited to 10A.  Unlike simple FET’s, they can’t burn out from a dead-short.  The outputs are current-limited, temperature-limited, and short-circuit protected, and will automatically shut off in the event of a potentially damaging condition.   Unlike other altimeters, you don’t have to worry that your battery is “too big”, as long as it’s a 2S Lipo.

How hard is the Quasar to assemble?

We’re not gonna lie, it’s not the easiest kit we make… it’s mostly surface mount parts, and there are a lot of them, on both sides of the board.   We DO pre-mount the baro pressure sensor and the GPS module for you, and the surface mount parts are mostly 1206-sized parts and SOIC packages (.050″/1.27mm pitch), so they’re definitely hand-solderable by someone with some previous soldering experience.   We recommend a 15W or so pencil iron or (preferably) a temperature-controlled soldering station, and you’ll NEED a lighted magnifier of some kind (we light ring lights).   If you’ve built any of our SMT kits, you should be able to handle a Quasar… it may just take longer due to the number of parts.   We provide the solder, so that’s one less thing that you have to worry about.

OK, I’m sold… what does the Quasar cost?

The Eggtimer Quasar kit lists for $100, regardless of the regulatory band.   See our Purchase page for prices of the LCD receiver, LCD-GPS Module, and Voice Module… an entire GPS/altimeter package with a GPS-enabled receiver and voice capability is much less than what many other vendors charge for just the GPS transmitter alone.