Disclaimer:
I don't know anything! No, really. I just came up with this idea, but I have no idea how to code and program. That said, I'm going to take this homebrew coding on as a new hobby. I'm literally starting from the very bottom. The adventure should be fun though!
Here's the idea:
I want to build an automated indoor blimp. I have 30 foot ceilings in my apartment and I thought it would be cool to have this little craft sailing around all day. I was reading the article on proximity sensors and it got me thinking. I just need to fill a ballon (or similar craft/vessel) with helium, and attach an Arduino powered propellor to it. I'd want this thing to slowly fly around my apartment, avoiding walls (a la proximity sensors), and flying in a random pattern. I'd need the propellor to articulate so it can change direction and fly around a room in a random path. It would only need quick bursts from the prop as it will just sail under it's own buoyancy. That is, when an obstacle or wall is detected, it fires the reverse thruster just enough to get it going the other way. Once the distance increases from the obstacle, the motor shuts off and away the blimp sails. The vessel will be filled with just enough helium to keep it at a specific altitude with all the components on board.
Down the line, maybe I'll have it report back to processing and have it map the room in at least a 2D format.
filled with just enough helium to keep it at a specific altitude
Does your air density vary so much in height? You probably take care to keep the heated air above your head only
I fear you have to do something actively for this. ( another distance sensor to the ceiling, controlling the volume/pressure of your blimp ? )
Alternatively, a helium balloon lifting 90% of its cord off the ground is pretty stable, but by far not that cool.
I got a toy indoor helicopter, which flies for 5 minutes until recharging. That's enough because controlling it manually means
a) you usually crash it much earlier
b) if not, it becomes annoying
I understand your goal is to have it cruising for hours, at least...
Any guess about power supply ?
At the moment, everything you've mentioned is last on the punch list. That's the easiest part. Because this thing is going to sail very slowly though the air and fire the motor for very short bursts, I don't imagine power consumption to be big. It's certainly something that a a bunch of Li-ion batteries can handle.
I need help focusing on the parts list and programing.
Maybe begin with some sort of toy RC balloon and use it as a start point? perhaps something like this:
That would cover a lot of your vehicle hardware needs. Hack that sucker down to motors and props and throw the rest in your junk box
I'd do my prototyping with the UNO but you'll probably need to shed a lot of weight for flight trials. Maybe a Nano? Maybe something even more stripped?
You will need positive altitude control because you'll never get it to remain stable at a given altitude otherwise. Can you use some sort of range finder to measure the distance to the floor or ceiling? The 'flying fish' balloons look extremely cool and are hopefully quieter than the propeller-driven blimps I've tried - those are too loud to be ignored - but don't seem to have reverse, which might be a problem.
The vessel will be filled with just enough helium to keep it at a specific altitude with all the components on board.
When my children were of an age to be amused by helium balloons, we used to joke after a few days when they were sinking to the floor (the balloons, not the children), that the balloons would "live" longer if you gave them an occasional hug.
Sure enough, the balloon would be given a brief cuddle and magically rise again to the ceiling.
The very brief contact with body heat was enough to cause the gas to expand, increase buoyancy and allow the balloon to rise into the warm air at the top of the room, where it would expand even further.
It would only need quick bursts from the prop as it will just sail under it's own buoyancy.
Unfortunately... no. That's like saying you just need to give a car a quick burst of power then it will roll down the road under it's own inertia. The fact is the air introduces a significant amount of drag to anything moving through it.
To see for yourself, get a neutrally buoyant balloon and give it a small push on the side. See how far it goes across the room.
The vessel will be filled with just enough helium to keep it at a specific altitude with all the components on board.
When my children were of an age to be amused by helium balloons, we used to joke after a few days when they were sinking to the floor (the balloons, not the children), that the balloons would "live" longer if you gave them an occasional hug.
Sure enough, the balloon would be given a brief cuddle and magically rise again to the ceiling.
The very brief contact with body heat was enough to cause the gas to expand, increase buoyancy and allow the balloon to rise into the warm air at the top of the room, where it would expand even further.
Active altitude control is almost essential.
A small heating element? It would be power hungry but may be cool to experiment with...
A small heating element? It would be power hungry but may be cool to experiment with...
Easiest is the up/down propeller solution of the BalloonCraft sample and hot air in the top part of your room, to have the blimp float on it.
For long time traveling eventually supported by automatic ballast weight drop (use sand instead of lead to be RoHS compliant) ...
Hoff70, thank you for that find! I happen to have a helium tank around and 22 foot ceilings. I ordered one.
Regarding your "Hack that sucker down to motors and props and throw the rest in your junk box", I think it already is hacked down to almost the minimum, weightwise.
iZepp - I like your attitude. It rejuvenates mine!
I think, however, that the Arduino is probably too heavy, not to mention its batteries. May I suggest a different twist? It also doesn't require sacrificing the blimp itself.
Say you mount only the proximity sensor(s) on the blimp. You keep the Arduino on the ground, with it's hefty power supply and hack and control one of the handheld controllers with the Arduino. It looks like only 3 digital pins are needed, for on/off of the three blimp motors.
You need to communicate and control the sensors via a radio link though. You might sequentially ping the forward, downward and right or left sensors in sequence. When you have your elevation and distances to the barrier ahead and left and right, then you ARduino program decides which motors to pulse on and for how long. Maybe even turn on the elevation fan until height reaches xxx.
The sensors take only 2ma so the batteries for them would not be too heavy.
It does introduce the problem of how to get the data back from sensors transmitted and received at your ground Arduino base.
Perhaps some R/C coolies will chime in!
Maybe the weight can be solved with just more helium and/or larger balloon.
If so, you could suspend the Arduino basket below the blimp and have 4 small wires going to the blimp ground and each of the three motors.
To enable dual, wireless and Arduino control, you would need to use 2 diodes in an "or" configuration, so that either the ARduino or the existing wire can provide current for a motor, yet current would not backflow into the Arduino or existing blimp circuitry.
The vessel will be filled with just enough helium to keep it at a specific altitude with all the components on board.
When my children were of an age to be amused by helium balloons, we used to joke after a few days when they were sinking to the floor (the balloons, not the children), that the balloons would "live" longer if you gave them an occasional hug.
Sure enough, the balloon would be given a brief cuddle and magically rise again to the ceiling.
The very brief contact with body heat was enough to cause the gas to expand, increase buoyancy and allow the balloon to rise into the warm air at the top of the room, where it would expand even further.
Active altitude control is almost essential.
With a continuously running propeller you have power to maintain altitude if there is some sort of control surface - measuring altitude is an issue (a barometric pressure sensor will do the short term but you have to compensate for changes in atmospheric pressure over time...
Something like a small brushless motor computer fan could be adapted - cut off the external frame, extend the fan blades somehow, as light as possible. These fans typically run at anything from 7 to 15V, btw, are fairly efficient and light.
Perhaps the simplest altitude control is to have the fan push upwards as well as along, and turn the fan on and off to maintain height. This has the advantage that when the battery dies it gently floats down and can be retrieved...
