Eggtimer Quantum - A WiFi-Enabled Flight Computer

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A piece of 1/4" od (1/8" id) pvc tubing about 1/8" high as a spacer on the top works too. Use a 1/4" long piece below the PC board so the optoisolators clear your sled. #4 x 3/4" machine screws are ideal assuming your sled is 1/8" thick FG and you're using nylock nuts.
 
kevinkal said:
I have some 3mm nylon screws, and some 4-40 steel screws to mount with.. but both of them have a problem with one of the two narrow mounting holes. The screws clip the WiFi board. How should I go about mounting this? Perhaps some silicon tubing as a conformal washer, used with a longer screw? How do you mount your quantum?
Click to expand...

I use 4-40 nylon screws on my Quantum to avoid the metal screw contacting parts on the board. You can also try 3/16 x 1/16 x 1/16 rubber o-rings on the 4-40 metal screws. Slide them on and use instead of a washer. If you also put an o-ring on bottom side of board it holds screw in place. I found these small o-rings at Home Depot.
 
cerving said:
Juicy is good... it's big and won't fry easily.

The typical deployment output circtuitry has one of the two legs connected to a common (ususally +V if you're using FETs, but we use BJT's so it's GND) and the other leg switched on/off by your deployment transistor, by the processor. The reason that NAR/TRA requires a disconnect on the deployment power is that you only have one thing - the transistor - between your battery and the igniter. If the transistor should fail (i.e. a fried-shorted FET) or you have some kind of glitch in your circuitry then your igniter is going to fire the instant that you provide power to it.

The Quantum basically includes a switch for the deployment power (an 8A/60W FET) that doesn't come on until near-apogee in flight, in addition to the standard BJT on the "+" side of the igniter. There is no direct connection between the igniters and the deployment power. For continuity testing purposes there is a 4.7K resistor on either side of the igniter to +V and GND, it lights up the optoisolator but the current through the igniter is going to be well under 1mA. For the igniter to fire, BOTH the FET and the BJT have to be turned on. They're controlled by separate outputs on the processor, and by separate events in the software. It would be virtually impossible for these to happen outside a real flight (or a user-initiated test). I was thinking primarily of airstart safety when I put this in, but I believe it also satisfies the NAR/TRA requirements for a L3 deployment power disconnect. Opposing opinions are encouraged and welcomed, of course... :)
Click to expand...

Now that the Quantum has been out and flown for a while, has its switched deployment power been accepted to satisfy NAR/TRA requirements for L3 deployment? It would be nice to cut down on the number of mechanical switches, but I'm concerned about trying to explain this feature in the L3 electronics package paperwork, and then gain oversight understanding and approval.

I was thinking of running dual redundant Quantums. I assume I could just switch WiFi connections to configure and arm each one separately.
 
sl98 said:
I use 4-40 nylon screws on my Quantum to avoid the metal screw contacting parts on the board. You can also try 3/16 x 1/16 x 1/16 rubber o-rings on the 4-40 metal screws. Slide them on and use instead of a washer. If you also put an o-ring on bottom side of board it holds screw in place. I found these small o-rings at Home Depot.
Click to expand...

I do the same in reverse, using 4-40 nylon stand offs and std screws.

Will get my rear in gear , update one resistor and do the update on two Quantums later today .. I also found a wifi switch that did not have the continuity terminal blocks soldered on

Kenny
 
kevinkal said:
Now that the Quantum has been out and flown for a while, has its switched deployment power been accepted to satisfy NAR/TRA requirements for L3 deployment?
Click to expand...

2.4 The capability must exist to externally disarm
all pyrotechnic devices on-board the rocket.
In this context, ‘disarm’ means the ability to phys
ically break the connection between a
pyrotechnic system and its power source.
 
jderimig said:
2.4 The capability must exist to externally disarm
all pyrotechnic devices on-board the rocket.
In this context, ‘disarm’ means the ability to phys
ically break the connection between a
pyrotechnic system and its power source.
Click to expand...

That could be as simple as running the negative lead off the battery & ground wire of the quantum or wifi switch out the vent hole for a single twist & tape connection

Sad , but meets the requirement

Kenny
 
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jderimig said:
2.4 The capability must exist to externally disarm
all pyrotechnic devices on-board the rocket.
In this context, ‘disarm’ means the ability to phys
ically break the connection between a
pyrotechnic system and its power source.
Click to expand...

KenRico said:
That could be as simple as running the negative lead off the battery & ground wire of the quantum or wifi switch out the vent hole for a single twist & tape connection

Sad , but meets the requirement

Kenny
Click to expand...


Thanks for the replies. For some reason, I had it in my mind that each pyrotechnic charge needed to have it's own switch/disconnect downstream of the altimeter. The case of an altimeter that contains a capacitor comes to mind, I'm thinking of the little capacitor that in on the two StratoLoggerCF altimeters that I have. Simply switching off or disconnecting the battery could still leave a charged capacitor on the altimeter which might be construed as a "power source" ~inline with the igniters. I don't know what the purpose of that capacitor is.. power filtering, output current boost, or perhaps even speaker output? I'm probably thinking "too much" on this detail.

I've been using Schurter 110/220v rotary switches and MW screw switches to control power to altimeters, which source their output current from the same switched battery. (I have the jumper wire installed on my Eggtimer Quantum.) Does a single switch to power the altimeter and thus it's outputs satisfy the L3 requirement when used in a dual redundant configuration?
 
You will need to make the case of what "physical" disconnect is effective. In the case of storage capacitors most should be completely discharged after a given period of time off. If that is the case and you have a standard procedure that insures that this time has passed prior to "loading", then a power disconnection should be justifiable. Its your L3CC that will make the ultimate decision.
 
A physical disconnection of a separate deployment battery will be 100% effective in the Quantum... there's no storage capacitor. For a L3 project, I would recommend using a separate deployment battery, it's totally glitch-proof. Note that the physical disconnect is a NAR requirement... TRA allows electronic power disconnect, although as has been previously mentioned it's up to your TAPs to decide what constitutes a disconnect. Feel free to have your TAP contact me if they have any questions about the Quantum's deployment power disconnect... I'd love to explain it to them, since it's different than any other altimeter.
 
Usually if you will get a email from the manufacturer (mmmm, Cris...) stating that the unit can be fully disconnected from the power supply when off via either a switch between the battery or that the Quantums system is safe enough without the separate switch ( I used a Quark and RRC3 on my L3 flights, so both Cris and Jim) then you have a good opening argument. My L3CC allowed me to use only a single screw switch between one leg of the battery and the altimeter, and on the RRC3 I jumpered the alts switch terminal so that a single screw switch on the battery was also the power on.
 
I need a launch controller capable of foreign a FirstFire Jr starter this past weekend, but only has an Estes AA powered controller. After a bit of pondering, the Quantum came to mind. I had a 1000 mAh 2s LiPo battery and phone ready with the Wi-Fi SSID setting.

It worked great. Just accessed the Test interface, confirmed channel continuity, entered access code (great feature), and pressed Test. Web page displays a great 10 - 0 count down and launch 5 flights perfectly.

I know this was not Chris' design intent for this, but it worked great!

Thanks for all your great kits Chris.
 
Firing an igniter like that was one of the design requirements for airstarts. Flight testing of the airstart software build is proceeding, I'm hoping for a release in the early Spring. It would help if we had just a little less rain here so Lucerne Valley wasn't a big mudhole all the time...
 
Did a few more 2-stage tests at TRASD yesterday... worked fine. Now I gotta build something out of FG, because I suck at guessing how much powder to use for little cardboard rockets (and I have the blown-up tubes to prove it).
 
Both. Two Quantums in the AV bay... one for separation charge/igniter, one for DD deployments.
 
I actually meant 'which one blew up the tube' :)

I'm assuming the dual deploy did, but I suppose that you might be able to burst the interstage and still get good staging. The first time, at least.
 
Oh yeah, that one was on an Estes Mongoose, AT D21 to AT D10. It only had one Quantum... one channel for the airstart (the booster was blast-separated, that worked just fine) and the second for the parachute at apogee. THAT one blew up the tube... I guess the parachute and wadding was a bit tight in the BT50 tube. The actual flight was just fine, although that D10 took about two seconds to light, it was the recovery that was a little sketchy.
 
D-D in a Mongoose?!! (!!)

Good heavens, how were you planning on getting the sustainer back without an Eggfinder wedged in there, too?

Wait, wait, don't tell me. An open patch of desert roughly the shape and size of Rhode Island?
 
Yup. The Quantum fits just fine, if you leave out the terminal blocks. There IS an Eggfinder in there too... more details on that one in about a month or so. :wink:
 
I witnessed both staged flights and Cris let me peek at the updated eGG screen in his phone. . Pretty cool.

Kenny
 
cerving said:
There IS an Eggfinder in there too... more details on that one in about a month or so. :wink:
Click to expand...

Am I reading too much into this or is there a new / improved product that I will just have to add to my Egg collection?!?!
 
The next Bong launch coincides with Cider Summit Chicago - so I'll be pouring rather than flying.

So aim for March, please!
 
cerving said:
Oh yeah, that one was on an Estes Mongoose, AT D21 to AT D10. It only had one Quantum... one channel for the airstart (the booster was blast-separated, that worked just fine) and the second for the parachute at apogee. THAT one blew up the tube... I guess the parachute and wadding was a bit tight in the BT50 tube. The actual flight was just fine, although that D10 took about two seconds to light, it was the recovery that was a little sketchy.
Click to expand...

Been there and done that a few times. This was posted before but demonstrates what happens in a tired old 4" rocket with a cardboard tube: [video=youtube;hMvT9BKzbUg]https://www.youtube.com/watch?v=hMvT9BKzbUg[/video]

Fincan survives and is going up for the second rebuild...... I'll put a glass wrap on the sustainer at least in the upper portion this time.

Blew two more rockets with cardboard tubes too. I feel your pain Cris.

Kurt
 
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