Eggtimer Quark FAQs
What is the Eggtimer Quark?
The Eggtimer Quark (just Quark from now on) is a simple two-channel deployment controller. Primaily used with high-power rockets, it allows you to fire two parachutes during flight: A small "drogue" chute that brings the rocket down from apogee to a controlled but fairly rapid descent, and a larger "main" chute that brings the rocket down from a much lower altitude to a soft landing.
This prevents your rocket from drifting thousands of feet, if not miles, from the high altitudes that are attainable with larger motors. Even at lower altitudes it's convenient, because you don't have to walk as far to your rocket. Less recovery time, more flying time...
How much does it cost?
The Quark is the lowest-cost two channel deployment controller on the market, at only $20. Like other Eggtimer Rocketry products, we sell it as a kit... you have to solder it together. In exchange for a little work on your part, you save a lot of money.
How hard is it to build?
The Quark is mostly surface-mount parts, so we don't recommend it for beginners. However, the parts are large by SMT standards, and we make the pads extra large so you have a lot of surface area to solder onto. You WILL need a lighted magnifier, though, and a good soldering iron with a very small tip. We include some special extra-fine low temperature solder to make the job easier on you.
What options does it have?
You can configure the Main chute for fire at 300', 500', 800', or 1000', using simple jumpers. For use as a backup controller, you can add one second to the Drogue chute delay, so it will fire a little bit later. This covers about 99% of the situations that you would be likely to require electronic deployments with.
What batteries do I need to use with it?
You can use just about anything from a 100 mAH 1S/3.7V LiPo all the way up to a 3S/11.1V LiPo. For most purposes we recommend using a 2S/7.4V LiPo pack, but 9V batteries work well too, and a lot of people use them. We recommend Duracell 9V batteries, since they have welded cells internally that won't come loose in flight. The Quark only draws about 8 mA, so it will run for many hours on just about any battery that will fire your igniters.
What igniters can I use with the Quark?
The Quark uses the signature optoisolated bipolar-transistor architecture that's in the Eggtimer Flight Computer and the Eggtimer TRS. It's highly immune to voltage dips caused by high-current igniters, because the bipolar transistors provide a natural current-limiting function (in this case, about 3 or 4 amps). You can use just about any ematch on the market without any problems, assuming that your battery can fire it; 2S/7.4V LiPo batteries work with almost anything which is why we recommend using them. We've even fired the standard Estes igniters with the Quark... but we don't recommend using them for deployment igniters, of course!
What if I only want to use one channel? Can I disable the other one somehow?
Yes, by simply using a 100 ohm 1/4 watt resistor in place of the igniter on that channel. For example, if you are going to use the motor's ejection charge for your drogue and you only want the main parachute function, you'd connect a resistor across the drogue outputs.
Is the Quark "mach safe" so it won't fire the parachutes during boost?
Yes. Like the tried-and-true Eggtimer, deployments are inhibited until launch has occurred and you've slowed down below 100 ft/sec for over one second continuously. Since this only happens shortly before apogee, mach transitions that occur well before that will have no effect on deployments. We also use a software filter to smooth out the baro-derived velocity to ensure that pressure-related "spikes" have minimal effect on the readings, including the ones on the ground; you don't have to worry about parachutes popping due to some wind gust while your rocket is sitting on the pad.
Can I ground-test my ematches and batteries with the Quark?
Yes. You use the programming jumpers to initiate a test, by simply inserting the appropriate jumper before power-on and removing it once the last-altitude beeping starts. You'll hear a "Ready for test" beeping, at which time you replace the jumper and the test will start after a long warning beep. By using a simple switch with a long piece of wire and a few socket pins in place of the jumper, it is possible to perform a "live" deployment charge test safely away from the rocket.
Do I get any data out of it?
Yes, it beeps out your apogee after every flight, and it also beeps out the last flight's apogee when you first turn it on. In addition, there is also a simple serial output that you can use to test the operation of the baro sensor, and it streams live altitude data out the serial port during flight. You can feed this data into the Eggtimer Telemetry Module (available soon) to get a real-time altitude display using the Eggfinder LCD receiver, and you can feed the altitude data into a computer and capture the data for display using Microsoft Excel or other spreadsheets/graphing programs.
Can I use screw terminal blocks with it?
Yes, on the deployment outputs. It's a build option... you mount the SMT parts normally, then mount all the through-hole parts and the terminal blocks on the bottom side. It requires one 4-position .150"-pitch terminal block (not included).