Eggtimer Rocketry
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FAQs

 

What is the Eggtimer Quantum?

The Eggtimer Quantum is a WiFi-enabled flight computer, used for deploying parachutes and logging flight data for later analysis.  It can also be configured as a smart timer, for use with airstarts and other "on the way up" functions.  It has functionality very similar to the Eggtimer Classic Flight Computer, but with the addition of an easy-to-use WiFi interface.


What makes the Eggtimer Quantum different than other flight computers on the market?

It's WiFi-enabled with a browser interface.  That means that you can use just about any WiFi/browser-enabled device (phone, tablet, laptop, or even an iPod Touch) to configure it, view flight summary data, download detailed flight data to a spreadsheet or other data analysis program, and to remotely arm/disarm the deployment charges.  You can also remotely test "live" deployment charges, safely away from your rocket.

In addition, there are also a few features unique to the Quantum, such as FailSafe main chute deployment that can save your rocket from a freefall such as a drogue failure.


Do I need a special app on my handheld device?

Nope.  Just a browser.  We've tested it with a wide variety of devices and browsers.  Not having to put an app on your device means that you don't have to worry about an incompatibility later on with an earlier version of the app, you don't need to burn up some space on your device that you may want for cute cat videos and the like, and you don't need to worry about some virus creeping into your device from yet another app.


What security features do you have to prevent somebody else from arming/disarming my Quantum?

Each Quantum has a unique WiFi SSID, and a unique 8-digit passcode.  They would have to know the passcode in order to connect to it.  With 8 digits, that's 10 million combinations... not gonna happen.

In addition, in order to arm or disarm the Quantum you need to enter a 4-digit validation code that changes every minute.  To disarm it while it's on the pad, you also need to enter a validation code.  This is not something that's going to happen accidentally... you can't "pocket-dial" your Quantum.


What is the range for arming/disarming the Quantum?

Typically it's about 150'-200'.  We don't recommend that you try to stretch it, of course... typically you'll step 10'-20' away when you arm it.  There IS a buzzer on board to confirm that it's armed, but you may not be able to hear it beyond 10' or so; you'll get an arming confirmation on your remote device anyway so that's not really a big deal.


Why would I need to disarm the Quantum?

Typically this is because you go to fly and you burn the igniter without lighting the motor.  After waiting the appropriate amount of time (at least 60 seconds), you approach the rocket, disconnect the igniter, then disarm the Quantum.  Once you install a new igniter you can re-arm the Quantum then connect the igniter (we always make sure the altimeter is armed first before connecting the igniter... don't ask us why!)


What flight parameters can I change?

From your remote device you can change:

o Drogue channel: On/Off, delay from nose-over, output type (pyro/servo), output duration, servo direction/width

o Main channel: On/Off, deployment altitude, output type (pyro/servo), output duration, servo direction/width

o Ascent and Descent samples per second (defaults are ascent:20 descent:2)

o Launch detect altitude.   Default is 200'.


What post-flight data can I see on my phone?

From your remote device you can see, for the last 15 flights:

o Flight number
o ASL altitude of launch site
o Temperature at launch
o Launch detect altitude & elapsed time from launch
o Low-velocity detect altitude & elapsed time from launch
o Apogee altitude & elapsed time from launch
o Nose-over altitude & elapsed time from launch
o Drogue deployment altitude & elapsed time from launch (if drogue is turned ON)
o Main deployment altitude & elapsed time from launch (if Main is turned ON)
o Landing elapsed time from launch
o Maximum velocity and elapsed time from launch
o Average acceleration in G's at maximum velocity from launch
o Plus all of the settings for that flight

Clicking on the "Detail" link from the Summary page downloads a .CSV file with detailed flight data that you can process using Excel or other data analysis programs.  You get time vs. altitude and velocity, both filtered and unfiltered.  Milestone flight events such as apogee and deployments are marked, too.  Generally, you're gonna want to use a laptop or laptop-replacement type tablet to analyze this data, but we've used WPS Office on an iPhone & 7" Android tablet to get a quick graph right after the flight.

What kind of airstart capabilities does it have?

The Quantum's two channels can be configured as an intelligent timer, triggered by the start of your flight.  You can set delays from 0.3 to 20 seconds, and you can add qualifications on the firing for altitude@time, velocity@time, and/or breakwire.  

Due to the fact that you have to explicitly arm it by entering the 4-digit arming code, and that the output channels are "dead" until the flight's in progress due to the dual-ended switching, it's the safest timer available.  It would be virtually impossible to make it start on the ground, and you can remotely arm it (and disarm it, if you burn an igniter) from at least 100' away.  That's a lot safer than having to stick your face right next to the rocket to turn on some switch on your airstart timer.


How high will it work?

We've designed it to work at a little over 60,000'.  That should satisfy everyone except for the most extreme altitude junkies out there.

 
How big is it?

The Quantum is about .9" wide and 2.5" long, and about .5" high (there are parts on both sides of the board that add to the height).  It weighs about 20 grams.  It will fit inside a 24mm/BT50 tube, which is smaller than most of the batteries that you're likely to use.  A 29mm motor mount tube makes a great home for it... you can use a pair of 29mm screw-on motor mounts to cap off the ends and provide easy access to the Quantum.


What kind of battery does it take?

We recommend a 2S/7.4V LiPo battery, 300 mAH or larger.  WiFi is rather power hungry... bigger is better.  If you're flying a smaller project (like one of those nifty 29mm carbon fiber rockets) you can get away with a smaller battery if you keep track of the battery voltage and don't wait too long after arming before you fly.  We DO NOT recommend using a 9V alkaline battery... they just don't source enough current for the WiFi radio, so you may get reduced range and/or intermittent communications.


What kind of igniters/servos can I use?

The transistors can handle a lot of current, 8A and over 30W.  You shouldn't have any problem lighting anything that you want to try.  We've done hot-wire cable cutters with it, setting the output to several seconds.

For servos, you can use any standard pulse-width-modulated hobby servos.  Just make sure the the output voltage isn't too high for the servos, and you'll need to connect them in a special way and connect an additional resistor across the deployment channels for each one (instructions on this are in the User's Guide).


I see that this is a kit... how hard is it to build?

We try to make it as easy as possible, but we don't recommend it as your first kit if you've never done anything like this before.  It does use a few surface-mount parts so you'll need a good lighted magnifier and a small soldering iron (15W or less recommended) with a small tip (.032" chisel-tip recommended).  The surface-mount parts are all 1206-size, which is pretty large by SMT standards, the hardest parts to solder are the memory chip and the optosolators since they're  on .050' centers.  We include special .020" low-temperature no-clean solder to make the job easier.

If you've successfully built any of our kits, the Quantum should be a breeze.


Since everything is done with WiFi do I still need a serial cable?

Not necessarily.  You only need the cable for two things... viewing the WiFi passcode and updating the software. Since the WiFi passcode is printed on the label of the module, you only need the cable for that if you lose or forget it.  Software updates are a very occasional thing, so unless some new feature comes along that you "must" have or some bug is fixed that affects you then that's not a big deal either.  Nonetheless, if you don't have an Eggtimer USB-Serial cable we recommend that you get one... they're only $5 and they work with every product we sell.