Smallest size electronics payload ever!?

[FROB]

Yes, folks, this is yet another poll, though there is purpose to this, if you vote and i hope you do, and even better if you post a detailed explanation of your preference, you could be richly rewarded! *
* (1 free rocket electronics draw for all participants who comment)

[Meat]

I am still pretty new to all of this so my comments wont really help a whole lot but I think its great subject .

[jj94]

I chose 38mm, but I should have done 18 or 24. At first I thought you meant what diameter rocket you would want it in. I chose 38mm cause it's closest to a BT-60. Then I realized you meant motor diameter. I'm a bit slow today. I have some 18/24mm rockets that I wouldn't mind putting an altimeter in.

[Microspeed]

I picked 13mm. If you could get enough functionality out of a 13mm board (at least altitude recording, perhaps/preferably a timing--deployment/airstart/etc. output, or more, it could be used in almost anything bigger. Plus, there are plenty of boards out there for the 24mm size and up that have deployment capabilities (PerfectFlite, G-Wiz, and up), and 18mm boards that will do recording (PerfectFlite). I thought I remember there once being a 13mm recording altimeter, but I haven't seen anything about it recently, but it would be a lot of fun to have something to put in those micro scale models (oh, the staging, clustering, airstarting, strap-on-ing possibilities...).

[Adrian A]

I picked 13mm. If you could get enough functionality out of a 13mm board (at least altitude recording, perhaps/preferably a timing--deployment/airstart/etc. output, or more, it could be used in almost anything bigger. Plus, there are plenty of boards out there for the 24mm size and up that have deployment capabilities (PerfectFlite, G-Wiz, and up), and 18mm boards that will do recording (PerfectFlite). I thought I remember there once being a 13mm recording altimeter, but I haven't seen anything about it recently, but it would be a lot of fun to have something to put in those micro scale models (oh, the staging, clustering, airstarting, strap-on-ing possibilities...).

Then there's the Parrot altimeter, which has barometric and accelerometer recording and 3 programmable outputs, fits in an 18mm tube and only weighs about 9 grams. To get it to fit in an 18mm tube, you need to order the version without the output screw terminal block, or get it with the screw terminal block and then sand off the corners.

I have a prototype baro-recording-only altimeter that will fit in a 13mm tube, but I put the development for it on hold. It may get restarted, though.

[FROB]

Hey Adrian, i have indeed read really good things about your altimeter- seems like a real top notch product!
...So now that we've both given your product a plug, as a rocket builder and flyer, would care to share which way you vote on the poll and why?

[MarkII]

I think that the Pico timer might fit into a Micromaxx body tube. I'm not sure what is required to power it, though. Some of my wife's quartz wristwatches have movements that would fit into a 10.5 mm (BT-3) tube, and possibly into a MMX tube. Someone with a little ingenuity (not me) might be able to adapt such a movement to perform some flight event, such as staging...

... or dual deploy...

Mark \\.

[Adrian A]

Hey Adrian, i have indeed read really good things about your altimeter- seems like a real top notch product!
...So now that we've both given your product a plug, as a rocket builder and flyer, would care to share which way you vote on the poll and why?

I voted for 18mm because it's the smallest size into which you can fit a full-featured altimeter, but on second thought I should have voted for 13mm because if I had a bare-bones 13mm altimeter I would use it for my club's A altitude record.

[FROB]

Hi Josh,
Actually you're not as slow as you think- were right the first time!

To clarify, the dimension in the poll refers to what size body tube the circuit has to fit into - in reality, it would be slightly smaller to get into a typical coupler with some clearance for tall components.
I assume though that is most critical in minimum-diameter rockets, where motor and body tube size is the same- that's why i used typical motor sizes.

In any case if the body tube diameter you would use doesn't correspond to any of those listed, please give the exact size (like BT-60) in your comments.

Thanks!!

[brianc]

I selected 13mm, but only because you omitted the MMX sizes...

[FROB]

MMX eh?.... thats 6mm - not easy .... wait..maybe if....
well, i suppose it could be done, but what about power? i don't know of any batteries that would fit! how would you power it?? it needs 3 volts.

If you're serious, well i could probably shrink my 13mm design just to claim the record.
Let's see...Barometer, 1 or 2 led's, 1 pushbutton, no room for a buzzer. Altitude read out by led's. I don't suppose you need this to work up to 100,000 feet? Could be certified for TARC use though.

One Pyro output? do you really need it? that means you have to fit another battery somewhere with enough juice to light an igniter - solve that and I'll ad it in there.
Homemade xmass light igniters work with as little as 50mA @ 3v, but that wont fit in the nozzle.

Maybe you could sign me up 25 people who want one with say a $10 refundable deposit?
I figure it would cost ~ $50 ea. Probably less but not more.
If anyone really wants something just for mmx size, send me a pm - if i get enough interest, consider it done.

[Micromeister]

Ah HMMMMM!!!! you missed a couple models sizes!!!

I have and used a micro altimeter that fits nicely with it's supercaps in a 10.5mm model body
and staging timers that work will in .281" and .316" (T2+ and T2++) size body tubes

As batteries packages and Supercaps get smaller these items i'm sure will also go down in size

[FROB]

Ah HMMMMM!!!! you missed a couple models sizes!!!

I have and used a micro altimeter that fits nicely with it's supercaps in a 10.5mm model body
and staging timers that work will in .281" and .316" (T2+ and T2++) size body tubes

As batteries packages and Supercaps get smaller these items i'm sure will also go down in size

Hey thats awesome! - do you sell these ?
can you share anything more about the design? - or how you power them? I know nothing about Micromaxx- what igniter's or e-matches can you use and with what power source to get something that small to work reliably?
You mentioned supercaps - but i haven't found anything smaller than 8mm dia.(0.314) that has enough capacity and low enough ESR. Same for batteries.

Are those common MMX body tube sizes? sorry for all the questions, I've become very curious since you guys bought up MMX- that's an all new topic to me.

[WillMarchant]

http://www.picoalt.com/

[MarkII]

Minimum-diameter Micromaxx tubing (like FlisKits BT-2.5 or ASP T-MM) has an OD of 0.281" or 0.282". BT-3, or T-10.5, is also commonly used in Micromaxx model construction.

I have heard of using super-capacitors to fire igniters in staging or air-starts, but I have never heard of them being used to power on-board avionics. Smaller super-caps could probably fit into a BT-3 tube. Micromeister will probably provide much more info.

I am quite surprised to see electronics used to stage MMX motors; it is something that I have been thinking (and dreaming) about for the past 4 years. I figured on using the PicoAlt micro-timer, but I wasn't sure if it would be wise to put an electronics package that was even as inexpensive as that one into a micro model. A combination of my lack of knowledge of electronics and my lack of financial resources has prevented me from pursuing the idea since then. Those with deeper pockets than my admittedly quite shallow ones have apparently been able to follow up on the idea, though.

Mark \\.

[FROB]

...I am quite surprised to see electronics used to stage MMX motors; it is something that I have been thinking (and dreaming) about for the past 4 years....

I didn't expect that either. how high can these things go anyway?
As far as staging, i think the 'chad' method easier, certainly lighter, and a lot cheaper, if not quite as reliable- with engines less than $1 ea, you can keep trying till it works perfectly. Is that not possible? Or does the new MICRO MAXX NE engines solve that?

I would imagine, these things being so small, that its quite easy to loose them outdoors in tall grass etc. If that's the case, a tiny beeper or flashing LED might be more useful. Do you agree?

I think it would be possible to make a tiny altimeter to fit inside BT-2.5 powered by a tiny supercap. It wouldn't hold enough power to reliably light an igniter, but it could power the altimeter for the flight and allow it to store its data to eeprom. In a BT-3 model, you can stack 2 or 3 watch batteries to power the thing instead, so it can keep going and flash a bright LED as a visual locating beacon after the flight, giving the altitude as a flashing pattern.

to keep cost down, it could detect launch when an external battery connection is broken:
There could be 2 tiny, low-friction pin sockets on the edge of the board that you'd line up with 2 tiny holes in the side of the airframe, so you can poke in a power "umbilical" of 24AWG solid wire from a pair of alkaline cells that stay on the ground near the pad. That would also charge the supercap.

Or for a few bucks more i can have a tiny 8G 3D accelerometer detect launch, and also log its data during the flight. That has some other benefits too, since it can act as user input device to program it.
That also might be handy to detect burn-out for use in staging. In that case you'd probably be limited to BT-3 size to hold a big enough supercap to do the job, with the lowest current igniters such as Q2G2.

I'd probably sell it as a kit with a couple of different size supecaps & battery clips that you can change depending on what you're doing.

How does that sound?

Hmm... it 'd be interesting to be able to do some a micro-scale models like a Delta III or Delta IV-heavy, with working drop-off boosters, eh?
Now i have to get some MMX igniters and run some tests....

[FROB]

http://www.picoalt.com/

Doh! now i remember....thanks for the reminder.