I have project in mind that would run on compressed air from the CO2 cartridge.
I would like to do all the pneumatic valves management from Arduino. Now, is there a safe and reliable way to operate various compressed air devices with microprocessor? Maybe using some relays?
What actuators are you working with I am also interested in doing something like this, never occured to me to use a CO2 cartridge though, clever idea.
It should be possible to control the actuators
I've worked with a lot of pneumatic systems at a oil refinery before I retired. I've heard of running pneumatics on N2 and of course air, however I think CO2 might be a problem, as it tends to freeze up as it's venting through the various small orifices that pneumatics switches and controls use?
Lefty
retrolefty, you are right on the money. CO2 freezes as soon as it exits the orifice. But it is cheap and ubiquitous.
Anyway idea is to make lunar lender, with a flight time of maybe 60 sec., running on compressed air and Arduino dong valve opening and closing. But the whole can not be bigger than 6" (15cm) and weigh less than 2 oz (1 Kg).
What other source of compressed gas, that is safe for domestic use can there be?
idea is to make lunar lender
You setting up a bank on the moon?
Don't fully automatic paintball guns use electronic actuators? They seam to do pretty good without having to worry about any freezing issues from the CO2.
digimike
thanks for the tip. I'll research on that
PaoulS
just a table-top one. moon landing, real one in 60's, was my favorite techie adventure
Digimike is correct in his statement that many paintball markers use CO2 as a propellant; after 5 years I have yet to see any freeze ups even on humid days.
DROBNJAK's needs to clarify his weight specification of “less than 2 oz (1 Kg)”.
If less than 2 oz (56.7 grams) then he is likely snookered since it would be impossible with the current technology to fit even the smallest Arduino MCU IC, battery, sensors, CO2 valve and CO2 storage into that little weight.
At 35 oz (1 Kg) the project is a lot more interesting, however one of the big challenges now becomes the amount of energy in the form of compressed CO2 (in a tank) that is required to loft/hover or fly the lunar lander.
DROBNJAK what are the flight characteristics of the device that need to be met? Does it need to hover or does it need to navigate either from point-to-point or on some particular path?
Remember that at 1kg, you will need to be able to store and deliver in a controlled manner enough CO2 to produce more than 1kg of thrust for 60 seconds. Assuming that it will be moving at slow speed and the aerodynamic drag will be negligible; then the amount of thrust required in excess of 1kg will be dependent upon the height you need to obtain plus any energy required for horizontal movement.
What other source of compressed gas, that is safe for domestic use can there be?
Please use CFCs.
We had an extreme cold winter in europe. 
You may want to look at propane (fairly inexpensive) or R-134, or perhaps some other liquid propellant.
just a table-top one. moon landing, real one in 60's, was my favorite techie adventure
DROBNJAK, I think you need to describe your idea better; here's what I think you may be going after (and if not, it would still make for a cool Arduino project):
You essentially want to create a physical "lunar lander" game of some sort; table-top size (perhaps a 1-2 meters on a side?) - so there is a base, with craters, landing areas, etc; and you are given so much "fuel" plus everything else to (hopefully) simulate a landing (and/or takeoffs).
As others have mentioned, you are not likely to get all of that (co2 and such for propulsion) inside the space and weight limits you have given yourself. Plus, you have to deal with regular gravity, instead of 1/3 gravity.
I want to propose an alternate (if somewhat less realistic) solution:
Use thin kevlar string (or thin fishing line) and electric motors. Place four of these motors, one each at the corners of the base table, and extend vertically a "tower"; set up a small winch reel on the shaft of each motor, around which the string is wrapped. These four lines would then lead up the tower, over a small steel loop, and down to a "point" - which is connected to the top of your "lander". Your lander would also contain its own microcontroller and such, with a simple wireless communication system - to allow communications from the master control microcontroller.
Essentially, the master microcontroller, thru h-bridges, would reel in and out the lines to allow you to place the lander nearly anywhere within the boundary of a cube described by the height of the towers and the area of the table-top board (practically, it will be smaller than this, but not by much). You could control the speed of the motors to simulate different gravity parameters (programmable, of course! Want to land on mars? no problemo!); there would also need to be feedback encoders on the motors, and there will be some interesting 3D math to solve to convert coordinates to reel/string/line lengths, but nothing impossible.
Using the wireless system to the microcontroller in the lander (powered by a battery), you could set things up to have it light LEDs for the "engines", make sounds, vibrate, whatever! If you can find a small enough 2-way communications system (maybe bluetooth?), you could have it feedback to the main controller its "orientation" status, or its "impact" on landing; or you could tell it to "explode" or whatever.
Put a black backdrop behind the rear-most towers, and the strings would be nearly invisible. Something like this would be the high-tech equivalent to the old-school "chopper rescue" spinny thing (can't remember what it was called) that were toys a long time ago (at one time as a kid, I had one that used a fan to act as the Starship Enterprise from TOS - if I hadn't broke it, then scavenged the motor - the thing would probably be worth a few bucks today).
If that is what you are going for, here's some inspiration...
CSingleton:
Sorry, I confused oz with lbs, I am European. Lunar lender is to be around 2 lbs or 1kg.
I would like it to fly/hover about 30-60sec. That should be realistic, practically you would have enough for one landing attempt. Same as real astronauts.
Main problem are valves. They need to be electronically operated. The only ones I found, ones used for air muscles, are 7cm (2.5") long and made of brass. Since you'll need six of them, that is huge amount of bulk and volume. Almost no room left for gas tank.
Other idea is to use Processing with joystick for control. And other idea is to use shock absorbers from RC cars on the legs of the lender.
But main obstacle is not the big booster engine, but the whole bunch of smaller nozzles that are meant to keep the vehicle vertical and stabilized.
Have you done any research on the actual lunar lander and the trainers NASA used to train the Astronauts how to use the actual lander? They had a heck of a time making the trainer simulate lunar gravity.
digimike:
I only have seen that video when Armstrong ejects midair after the simulator begins to malfunction. It would be nice if you had a good link with more info. I can read about landing on the moon again and again, without ever getting even slightly bored :
anyway, while we are gathering ideas and knowledge in this thread, if anybody wants to try it,there is my favorite lunar lender game. It had been done by some Flash programmers here in UK. They are quite into Arduino themselves.
DROBNJAK
Don't get me wrong, with the incredible developments that have happened in RC aircraft over the past five years and their successful commercialization there might be hope for you and your project yet. However, until you solve the problem with storing and deploying (in a controlled manner) the energy for the main thruster . . . maneuvering thrusters are a moot point.
If you want to continue to receive helpful answers on this topic from the forum members, I think that you should follow CrOsh's recommendation that you better define the intended use of the lander and its requirements. To date you have just tossed a relatively simplistic description of what you want to do.
anyway, while we are gathering ideas and knowledge in this thread, if anybody wants to try it,there is my favorite lunar lender game. It had been done by some Flash programmers here in UK. They are quite into Arduino themselves.
That was a pretty fun version of that game - although I think my all time favorite would be the text-only version (a version can be found in one of David Ahl's BASIC Games books; to truely appreciate it I am told it needs to be played over a 300 baud teletype, I never got that chance as I was too young).
As far as your simulator is concerned, I really don't think you are going to be able to do it - whether its 2lbs or 2 ounces; simply because you are fighting the earth's gravity. You are trying to stuff 10 pounds of potatoes in a 2 pound bag.
These are what they used to train the Apollo astronauts, I believe:
http://www.astronautix.com/craft/apoollrv.htm
Notice how big they were compared to the single test dummy pilot...
;D
Most of that space was for engines and fuel, just to counteract the earth's gravity for the simulation and training. It won't scale down, unfortunately (if it could, we would have all sorts of cool toys available by now).
If you are insistent upon a non-tethered vehicle, then I would suggest thinking about how to do it in another medium in which you can make the vehicle neutrally bouyant for the size you are looking at; a large clear acrylic tank (not cheap) filled with water or mineral oil could work. Electric motor thrusters could be used as the "rockets".
CSingleton
Problem is I do not know much. Last weekend I managed to hook up 16x2 LCD to Arduino, with "Hello World". I really need help from guys who know more stuff.
cr0sh:
Thanks for the great link. I am reading it right now.
If any of you guys is trilled enough to do this one, just fire away. It would be very exciting if anybody can complete this one. As "cr0sh" rightly observed, there are so many RC model components that most things are already resolved.
It is unusual that nobody in US hadn't picked this one up before? It should be a question of national pride.
As "cr0sh" rightly observed, there are so many RC model components that most things are already resolved.
I didn't "observe" that, another poster did; but thanks for the attribution!
It is unusual that nobody in US hadn't picked this one up before? It should be a question of national pride.
In a country divided up over a health care bill because it might -gasp- somehow fund abortions? Are you joking?
The vast majority of my fellow countrymen, notwithstanding the few on here and elsewhere, are tards who would rather scream about doing something, instead of doing it.
Then, when they do "do it", it gets offshored.
Your biggest issue will be to get enough porpellant and still keep the weight down. So the proposal for strings is a simple solution of course. But once you would allow for strings, why not provide the propellant from outside? Somehow in the style of this:
Udo