New and need direction with a design project
darius_n
Posts: 6
Hello,
I'd like to apologize if this isn't in the right category, I just tonight came upon this site.
I've been directed towards this website from a university professor at McGill University in Montreal, Quebec, Canada. The reason I've been directed here is because I'm working on a design project for my engineering degree and it will involve the use of electronic components that she felt I could find alot of information on from this company / website, and I figured what better than to ask the community here.
I'm not very experienced with electronics beyond a basic circuits course, nor do I know much about all of these wonderful controllers and sensors that seem to be available from Parallax, but I'm hoping that people here can guide me in the right direction.
The design problem is the following:
Ten large machines are being used to gather crops, and often due to inexperienced operators and night conditions the machines collide with each other or other large obstacles and cause damage to the machines, thus rendering them inoperable until fixed. This costs alot of money to the machine owners.
The solution we're ( a collegue of mine and myself) are aiming for is a detection system that will warn the operators of large obstacles, or other machines in the near vincinity so that the operators can be more vigilant while operating the machines. We figured through limited discussion that the best way to do this is to set up a sort of infared sensor network on the machine that can detect when the machine is close or in a certain range of another large object and then light up a display pannel and having a tone sound off, thus warning the operator.
We're obviously looking for a cost effective solution here, but I'm open to any and all ideas. I've heard about sonar sensors, laser sensors, infrared sensors.... but quite honestly I'm not technically proficient enough at the moment to know which would be better suited for this problem.
We're about to submit out proposal document tomorrow, so we have alot of ideas on paper - but the feasibility and where I can get information on what to read or how to best complete this project is sort of lacking at the moment, and I'd like your input on what/where you think I might need to look into in order to become more technically proficient and understand better the components that Parallax has to offer and how we could use them in our design project.
Thanks for any insight.
Post Edited (darius_n) : 3/27/2006 2:30:51 AM GMT
I'd like to apologize if this isn't in the right category, I just tonight came upon this site.
I've been directed towards this website from a university professor at McGill University in Montreal, Quebec, Canada. The reason I've been directed here is because I'm working on a design project for my engineering degree and it will involve the use of electronic components that she felt I could find alot of information on from this company / website, and I figured what better than to ask the community here.
I'm not very experienced with electronics beyond a basic circuits course, nor do I know much about all of these wonderful controllers and sensors that seem to be available from Parallax, but I'm hoping that people here can guide me in the right direction.
The design problem is the following:
Ten large machines are being used to gather crops, and often due to inexperienced operators and night conditions the machines collide with each other or other large obstacles and cause damage to the machines, thus rendering them inoperable until fixed. This costs alot of money to the machine owners.
The solution we're ( a collegue of mine and myself) are aiming for is a detection system that will warn the operators of large obstacles, or other machines in the near vincinity so that the operators can be more vigilant while operating the machines. We figured through limited discussion that the best way to do this is to set up a sort of infared sensor network on the machine that can detect when the machine is close or in a certain range of another large object and then light up a display pannel and having a tone sound off, thus warning the operator.
We're obviously looking for a cost effective solution here, but I'm open to any and all ideas. I've heard about sonar sensors, laser sensors, infrared sensors.... but quite honestly I'm not technically proficient enough at the moment to know which would be better suited for this problem.
We're about to submit out proposal document tomorrow, so we have alot of ideas on paper - but the feasibility and where I can get information on what to read or how to best complete this project is sort of lacking at the moment, and I'd like your input on what/where you think I might need to look into in order to become more technically proficient and understand better the components that Parallax has to offer and how we could use them in our design project.
Thanks for any insight.
Post Edited (darius_n) : 3/27/2006 2:30:51 AM GMT
Comments
I think there are people who frequent this forum that may be able to help but we'll need a bit more detail. Like for example what kind of machine is it, a combine... a hovercraft? What are you trying to harvest and what are the field conditions? What are the "large objects" that are the obstacle? Cows, trees, buildings?
When I think of harvesting at night I think of things like lights to see where I'm going. Here in the midwest, there are lots of times when farmers work late into the dark during harvest season and they have big lights on their combines to see what they are doing. I'm having trouble understanding how an operator can see well enough to see what they are harvesting but can't see to avoid hitting another huge machine.
If I were having expensive machine damage due to lack of training, I think I'd intensify the training. That's just my opinion.
Lee
How far away are these machines from each other....obviously if you're concerned about collisions they'll get fairly close, but what's the furthest way they'll be?
Do you just need object avoidance? Or do you need to control them accurately enough down a path as well?
You could outfit each unit with a GPS and an RF transmitter that will send it's position out to some central computer that will then compute where each one is on a map.
Then you could transmit back to those units and have a stamp interrupt the machine to take action.
Map out all the obstacles in the field and have the 'central computer' command the machines to steer around them.
Ir range detectors are good, but only out to a certain range and then there's dealing with light conditions (modulating your output is required).
Laser range finders are good but $$!!
Ultrasonic may not give you the range you need to keep things safely apart.
Any range finder can be used to pan back and forth across an area looking for changes in obstacles.
Multiple IR sensors might conflict with each other...same with ultrasonic....so your timing and spacing has to be on!
Anyhow, there are ways around this ifyou give some more details!
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·
Steve
"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."
And I agree with Mr. Harker that they should probably spend more time training the people but the reality of the fact in this scenario is that these machines are used practically 24/7 with undertrained / underqualified operators thus resulting in MOST of the damages caused to the machines are due to operator negligence at night. These combines that they are operating do not have adequate vision for anything but front direction of the machine, and alot of damages are done when turning, or backing up. (Also running the machine into a ditch - but I think at this point in time it would be more complicated to solve the obstacle problem and ditch problem together, than simply the obstacle problem alone. Perhaps once I've nailed down one aspect I'll try to address the other)
I'll try to shed some more light on the situation here.
The machines are combines, they will be harvesting short crops like peas and beans.
The machines will probably be moving about 5-10 km/hr (I'll get back to you about the exact speed)
There should NOT be anything lower than the crops that machines could hit. We want to make sure the machines don't hit each other, or large trees, buildings, or other smaller trucks/vehicles like a pickup truck or car that managers drive out into the field when checking up on the guys etc. (It's happened about twice that somebody has almost gotten killed by one of these machines backing up - so it would be intresting to see if this system could be setup to detect a person also)
The machines will stop and go, and they will move around and turn - the machines also will need to operate within short distances of each other. I have a feeling that they need to be less than a few meters apart. (Again - I'll get back to you about the exact distance shortly)
What we've thought of was multiple infrared sensors located at key points on the machine, above the level of the crops. We were hoping to have perhaps 4-8 different infrared sensors on a machine all around, sort of covering 360 degrees around the machine (or at least the key cardinal points), and the sensors would be connected to a small light pannel that would light up corresponding to the infrared sensor that pickedup a disturbace/object in it's path. But as you mentioned steve_b there might be timming and spacing problems associated with this that I'm unaware at this moment in time how that would work.
We were told by a professor that GPS might not be accurate enough since our machines might have to work as close as a few meters apart. But I will look into what high end gps systems have as a resolution. (I know the military has some that are as accurate as 1m - but for civilian use; I understood they were much less accurate) The other problem with using GPS is that these machines are essentially like big rectangles (shape wise) and a gps will take a point and a radius - thus not effectively representing the shape of the combine machine, this was one of the main reasons we were directing ourselves towards other types of sensors.
Thanks for the replies
Darius
Position several about the machine, and read each one in turn.
This would return distance within the range of the unit, as well as detect "living" presence (as long at it was within the sensor's cone).
The code for this would be a simple modification of the demo program the sensor comes with.
The units are small, and somewhat inexpensive.
One drawback, I'm not sure how to mount them to protect them from weather.
....
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Just tossing my two bits worth into the bit bucket
KK
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Sounds to me like all you need is some better lighting and maybe a video camera for backing-up. And of course an operator who gives a damn.
Bean.
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"SX-Video·Module"·available from Parallax for only $28.95 http://www.parallax.com/detail.asp?product_id=30012
"SX-Video OSD module"·available from Parallax for only·$49.95 http://www.parallax.com/detail.asp?product_id=30015
Product web site: www.sxvm.com
Coming soon... Cheap 4-digit LED display with driver IC·www.hc4led.com
"Sometimes it is better to remain silent and be thought a fool, than to speak and remove all doubt."
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Now, yes you're right, why would Joe blow care about the warning system if he's not vigilant enough to avoid collision ? Well, we're assuming these are accidents and we'd like to treat them by giving the operator a heads up, and a signal to "watch out" or else you might hit something. As for the "false alerts" well, that's why I'm here asking for information and advice [noparse]:)[/noparse]
Thanks
Darius
In both cases, I suspect that the technology needed will not be cheap. While Parallax's sensors are indeed great for experimentation and small projects, I wouldn't want them to be in charge of notifying a poorly-trained operator at night that there's something 30 cm in front of them [noparse]:)[/noparse]
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Truly Understand the Fundamentals and the Path will be so much easier...
Post Edited (Tom Walker) : 3/27/2006 4:22:41 PM GMT
Interesting project. I think some more thinking on the process of harvesting will let you better define the needs of any system.
For instance, when harvesting with a combine type machine, it is just not efficient nor effective to expect any machine to be going in any direction at any speed. You need contraints; for instance, the machines I work with generally follow a row-by-row pattern, down a long row with a turn at the end. Preferably the machine doesn't have to back-up during the turn. Secondly, if more than one machine is working on a particular plot, who says they have to be right beside or behind each other? Put some space between them. I mean, you're harvesting low crops so visibility shouldn't be an issue.
When I first got into machinery automation, many of the "bean-counters" thought technology would let them hire dumber and dumber operators. What happened was that the high tech machinery was more easily put out of commission by inept operators and required more maintenance. Now, more progressive managers see that technology lets an already smart ( or well trained ) operator get the most out of the machine....but it won't operate the machine!
Anyhow, if you start out with machines expected to be separated by some distance, the accuracy of general GPS is probably OK. Or, for better accuracy, use one with a local differential transmitter and increase accuracy to less than a meter or so. Then, set up a system of Stamps with wireless transmitters which do two things: first, they broadcast their GPS position, then secondly listen for the GPS coordinates of their neighbors. All machines in a field do the same. If the coordinates sent and received start getting too close, an alarm is sounded.
It would make an interesting project ( ie not trivial) in its own right to workout the communication protocols. But, if you could buy it at Wal-Mart, everyone would already have one!
Regards
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·1+1=10
Ultra-sonic solutions will be able to detect things within 10 feet of each other, I believe.
Perhaps you need a 'layered' solution -- GPS for generic navigation, then ultra-sonic for 'close-in' avoidance warnings.
Along with the light beacon idea....use RF beacons.
If you google for some HAM beacon or fox & hound games, you might find some interesting circuits.
What you do is give each machine an rf transmitter with a different frequency. Each machine then has a filter for each of those frequencies and an rf power meter.
Switch between the filters to read the S/N ratio of each transmitter....when the Signal gets too high, then you must be near another one....sound an audible alarm and call attention to the driver.
Hard part might be the rf power meter part. It'd be nice to have something output a voltage for its indicated power...then maybe use the stamp to read that.
Use a dipole antenna for all around sensing.
Down the road you might look at a rotating antenna....this might give you the option of direction....although, if you can read the power for a frequency from multiple machines, you could easily triangulate where they are.
I like RF....this sounds fun!
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Steve
"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."
Jonathan
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www.madlabs.info - Home of the Hydrogen Fuel Cell Robot
In theory, you could get some of the 'line-sensor' modules, make a bigger 'work-space', put lines on the base representing the rows the combines are harvesting, and see how often your two BOE-bots come close, avoid each other, or collide with each other or the walls.
I cant explain my gratitude folks, in less than a few hours here I've gotten so much material to start reading about and understanding how things work, that I actually feel exicited about all these ideas being thrown out there. I definitly have to lookinto ultrasound, and RF - so far those are the two things that have stuck with my limited knowledge so far. But you all are being a great help in stoking the fire.
This project will have to be completed by december, so I have plenty of time to work on a basic system and hopefully create a a more complex system. I like the GPS infor that I'm reading also - it definitly sounds possible now as before I had slight knowledge about it, and thought it was a lost cause.
Well, thanks for now [noparse]:)[/noparse] - I have to present a presentation about my finished propsal tomorrow, and I'll definitly be suggesting some ideas that have been presented here as best as I can, and with what's been suggested I feel almost certain that I might start one thing, and end up with some complete different (more effective) system thank to you folks here.
Cheers
Darius
That being said; I can see it being a little pain in the butt to farmers who've never had to think of something like this to always now think of "Taking their transmitter" with them.
So far, I'm intrested quite a bit in the RF detection of each machine towards one another... and I'm assuming from what's been said here Ultrasound would be a better choice compared to IR to detect small pickup trucks, or persons around the larger combines.
How would they be secured and not-prone to damage from weather/environmental conditions. Let alone the vibrations that a large combine machine would be emitting. (Would the machine operating be a problem for any other sorts of sensors?) So if perhaps RF transmitters and recievers were used for the machines, what do you think would be a viable method to pick up other objects around the combines whether they be man, truck or tree ?
Thanks [noparse]:)[/noparse]
Darius
I've used post-processing DGPS and received sub-meter accuracy.· This again requires one GPS to be located at a surveyed benchmark, and both GPSs to record data from the same satellites.· The software then calculates the error·between the 'fixed' GPS and the surveyed point, then applies that·correction to the 'mobile' GPS.
If your university has a Civil Engineering program you should be able to get a great deal of information from them.
Good Luck,
Brian
We have submitted our propsal for the project and it was approved
We've put an acknowledgment in our report of all you folks here in these forums for your help, and we'll try to keep you informed on the progression of this project.
Thanks, and you'll be hearing from us sooner than later hopefully, as it's the end of the semester, finals are here and then during the summer we start to construct this system.
Darius