which microcontroller to use?
we are planning a bot that will use two servos to hunt for a radio beacon, which microcontroller should we use? I knoew everyone has their favorite but we want the cheapest, simplest controller available, I was looking at parallax SX series but maybe I should go with the basic stamp 2?
Comments
On the other hand, the Stamps are really simple to use, but they're more expensive.
Do consider the Propeller. The Protoboard is only $30.
what we are doing is taking a radio beacon in a remote location, using the stamp to run 2 hobby servos to home in on it using 2 recievers with dipole antennas, looking thru the documention about it and it looks like a good match.
A Propeller USB Protoboard runs $40, but is ready to go with only a few cables (mini-USB to USB, power cube or battery pack).
A Stamp Super Carrier Board is $20 and you may need a USB to Serial adapter ($20 with cable) if you don't already have a compatible one. You'll also need a Stamp module ($50 to $80 depending on features).
where are you seeing the BS1 for $30? also on recommendations it says
BASIC Stamp Modules
OR purchase one of the minimum requirement options and download manuals online:
- BS2 OEM + Serial Cable + Breadboard + Power Connector
I have a serial cable, breadboard and power connection will have to be custom for our project anyway.So I'd need the BS2 OEM for $30 or do i need a stamp with it?
I was just suggesting that you look at it. It's quite limited in terms of program size, but your task seemed simple enough. The BS2OEM is probably more suited to your task.
The BS2OEM is the Stamp, just using non-surface mount parts to form a larger "module" than the BS2 24-pin Module.
I am off to the oshkosh airshow and wont be back for 3 weeks, i'll probably be ording it when I return.
oh, I've been vauge about the application. directed rocket recovery system. a steerable parachute, and possibly guidance for the rocket itself in later design phases. if the BS2OEM works we shoudl be able to grab a few homework boards and use them instead.
oh I bet you'd like to see some video of our project http://www.youtube.com/watch?v=Yaz_t6IBAKs
Post Edited (tater) : 7/22/2009 3:16:23 PM GMT
Gads, Tater! What a beast that thing is! Did you set off NORAD alarms on launch? [noparse]:)[/noparse])
- Howard
... who never graduated past an Estes D engine...
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but thats not what the stamp is for, I figgure i need about 3-4 of them for recovery guidance for the HALF scale (18 ft long 40" dia)
anyone wanna do the programming? hey parallax? want some free* advert space?
*free as in send me some stamps to get it working [noparse]:)[/noparse]
well, forget the freebee stamps, why not go full scale and go for the next X-prise? hehehe
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and probably wouldn't give parallax full ad space, unless they want to start ordering all the supplies i need(about $2k for the half scale, $20k for the full) but I could see their name full length along the leading edge of one of the fins for the hardware i'd need from them
granted, i'd prefer to sell off space on the rocket in 2x4ft slots, but i'd be flexible.
You know that the Wisconsin Space Grant Consortium contest three years ago was high power spot landing, presumably using steerable parachutes, right? No-one got the steerable chute thing working properly - my group had successful flights with simple radio-controlled deployment of normal parachutes, and won a "non-engineering" prize. Are you planning to steer the whole thing, or just the capsule, using a more standard chute for the booster part? I assume you're going to use radio control for steering, right? You're not planning on autonomous guidance?
The best design that I saw was from a UWM team, and had servos mounted in a parafoil-style parachute, and the servos were intended to steer the chute by selectively collapsing cells in the parafoil. That solved what seems like the biggest issue to me: how to prevent the mechanism from being torn apart by the stress of parachute deployment. I'd think that the sudden yanking on the shroud lines that happens when a chute opens is pretty likely to damage even a very high quality servo (though I admit I haven't looked into the real expensive upper end of the servo price range). Unfortunately, the UWM rocket was destroyed when they were accidentally given a motor (K550) with an ejection charge installed, rather than a plugged one. Their rocket wasn't designed for motor deployment. The results were ugly.
I can understand the headaches on guideable(?) recovery, havent researched it yet, like the collapsing cells idea, and might steal it. and we do plan on autonomous guidance in the future, but we figgured doign the recovery first will soften the paranoids to the active guidance on large model rockets. I bet bunny would like it if we could steer a rocket safely away from people in a lawn dart moment.
back on topic, 2 BS1s for fin guidance, one for capsule recovery, another for booster recovery(4 total maybe). ham radio for beacons with modified foxhunters for telling the stamps where.
I am planning on having a couple 7ah gel cells on the half scale for power, hybrid motor with an avg thrust around 1000n and will need to use bong i think. when i get back to the HQ (dogsitting now) i'll be laying out my master plan for the next 6 months.
I'm sure this has been thought of before, but why is this a big problem. Assuming that the rocket is fairly large (aka, indoor space isn't much of a concern) then can't you have a retractable bar that is braced against the structure of the rocket? Basically, it would have all the lines of the parachute attached to it via a loop in the line, with the lines continuing on to the servos. The chute deploys, the bar is slammed into, and a few seconds later the bar retracts and the servos get a couple of inches of jerk.
I tried to draw a picture, but it was in paint and it looked terrible.
It's doable, I imagine, and probably something that rocketeers should be working on, as it'd have quite a few applications. But whenever I think about this kind of thing, I run into the question "how do you have a part that is strong enough to hold up to those kinds of forces and yet can be moved?" (and keep in mind that it also has to be fairly light, and that the power supply for moving it can't be a big heavy thing either). Five years' worth of college rocketry competitions have shown me a lot of engineering groups' proposed solutions to these kinds of problems - and have shown me a lot of ways that things can go wrong:
http://tinyurl.com/5dkba5
http://tinyurl.com/563ard
http://tinyurl.com/5cuaz5
http://tinyurl.com/69lecz
http://tinyurl.com/6pm9zw
http://tinyurl.com/6yrrvk
http://tinyurl.com/5k8dek
http://tinyurl.com/6qr4a7
http://tinyurl.com/58wcnw
http://tinyurl.com/5bkuc2
I don't think you guys have posting anything off topic or out of the forum's scope... I mean, a rocket with electronics is just a robot without treads and gripper arms, isn't it?
> how to prevent the mechanism from being torn apart by the stress of parachute
Aren't the bunge cords on the chute supposed to buffer that??·· Cool videos --- yikes, the one's with chute failure are *painful* to watch!
cheers
- Howard
(itching for some nichrome wire)
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I've been busy, might be getting something interesting up soon
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Some kind of rigid device to absorb the yank and then be retracted would be a good alternative, if you could figure it out.
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Tia'Shar Manetheren