Sensor application for detecting height of a plant.
edlikestoboogie
Posts: 71
Although this question is not microcontroller specific, the basic stamp forum seems to be most active. I will build the prototype of this model using the BS2.
I have this radical idea for a machine that trains a plant. Basicly a wooden box is suspended above the plant by a rope that is connected through a pulley onto a motor controlled by the BS2. The box will also have a sensor that is detecting the height of the plant by offsetting the sensor's position by a foot below the box. The box will have a small piece of string about a foot's length to keep the plant up. The idea is to keep the string connecting the plant and the box at firm tension. This will be done by sensing the plants height and pulling the box with the motor. I have included a rough drawing outlining this concept. My question is: what kind of sensor should I use to detect the plant's height? I can't think of what to use. Infrared wouldn't work, because I feel like the plant is so skinny, that it might not be able to detect it. Plus this would be used on sunny days, which might mess up its readings. I was thinking about using the sonar device that parallax uses. The one to detect distance for robots. Any suggestions?
I have this radical idea for a machine that trains a plant. Basicly a wooden box is suspended above the plant by a rope that is connected through a pulley onto a motor controlled by the BS2. The box will also have a sensor that is detecting the height of the plant by offsetting the sensor's position by a foot below the box. The box will have a small piece of string about a foot's length to keep the plant up. The idea is to keep the string connecting the plant and the box at firm tension. This will be done by sensing the plants height and pulling the box with the motor. I have included a rough drawing outlining this concept. My question is: what kind of sensor should I use to detect the plant's height? I can't think of what to use. Infrared wouldn't work, because I feel like the plant is so skinny, that it might not be able to detect it. Plus this would be used on sunny days, which might mess up its readings. I was thinking about using the sonar device that parallax uses. The one to detect distance for robots. Any suggestions?
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Comments
take and make two "7" brackets, orient one 180 degrees from the other so that the two shorter sides can hold onto one another. this is the tricky part, take a force sensor· and you sandwich it where the two "7" brackets meet one another. one "7" is attached to the string leading to the BS2 motor, the other bracket attaches to the spring leading to the plant, see diagram. and parallax gives demo source for interfacing this sensor with your BS2.
/ / / / / │ ────────│ │ <──┼──────── Flex force sensor └─────── │ / / / / / | |<----------To spring and plantNot sure how successful the setup will be, but it's possible you can interface the Ping sensor as well, it can measure to the millimeter if this is sufficient, don't know the resolution of the force sensor. I'm running a Propeller, Ping))), and have them interfaced with the PC using the Prop Terminal (a debug window for the prop), the resolution is good, update·speed is unbelievable!
You may want to give the propeller a look having ALOT more processing power, a TON of more memory, and twice the I/O pins. and once you get the concept of the SPIN language it's cake to interface stuff with minimal components like·sensors, mouse/keyboard, TV's, CRT Monitors, LCD's, you name it! I came from the BS2 (I have two), it's a cool MCU, but the prop can just blow it out of the water!
Take your project for example, you can easily interface an LCD display, the force sensor, a Ping))) sensor, a little winch motor, keyboard and mouse for an input, have it do some data logging... all in parallel, without it even breaking a sweat!
In any case, good luck with it.
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Definetly a E3 (Electronics Engineer Extrodinare!)
"I laugh in the face of imposible,... not because i know it all, ... but because I don't know well enough!"
Post Edited (RinksCustoms) : 6/11/2007 6:17:31 AM GMT
http://forums.parallax.com/forums/default.aspx?f=5&m=3282
And one more recent for the Propeller:
COIL_demo.zip
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Tracy Allen
www.emesystems.com
In the Propeller Education Kit Labs, there is a lab that deals with metal detection.· This particular lab uses a single loop coil constructed from a piece of hookup wire only 3 inches long.· Using the circuit configuration in the lab, a spring/coil in place of the 3 inch hookup wire should be a piece of cake. You will however need to lower the resonate frequency as it will likely be much less for the spring than the single loop coil which is about 50MHz.
Under "Counter Modules and Circuit Applications" from the 'Propeller Education Kit Labs"·link above·PE-Kit-Counters-Lab-v0.81.zip
Take a look at the PDF on page·43 - "Metal Detection with PLL and Positive Detector Modes and an LC Circuit"
Quote from LAB:
"Inductors are coils that when placed in a circuit have the capacity to store energy. They get used in many types of applications, one of which is metal detection. There are lots of different kinds of metal detection instruments aside from the ones you may have seen passed over the sands on just about any beach on any given weekend. Other examples include instruments that identify the type of metal, check for stress fractures in metal surfaces, and precisely measure the distance of a metal surface from an instrument.
Even though there aren’t any inductors in the PE kit, there are lots of wires that can be shaped into metal loops. When current passes through a metal loop, it becomes a small inductor. This portion of the lab demonstrates how a cog can use two counters, one in PLL mode and the other in POS detector mode, to send high-frequency signals into an LC (inductor-capacitor) circuits input, and infer the presence or absence of metal by examining the circuits output signal."
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Beau Schwabe
IC Layout Engineer
Parallax, Inc.
Post Edited (Beau Schwabe (Parallax)) : 6/11/2007 4:20:18 PM GMT
There must be more to it than that though, I must admit I have no idea what is required to train a plant!
Rich H
The more weight that goes in to this wire (or more tension created) the strings frequency increases.
Like plucking a guitar string and turning one of the headstock keys to tighten the string. The frequncy/note of the string increases with tension.
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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."
edlikestoboogie, why do you want to train the plant in that manner? Grape vines etc etc have been in training for ages, on trellises and all kinds of supports, but I had never heard of a tensioning system.
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Tracy Allen
www.emesystems.com
Post Edited (Tracy Allen) : 6/12/2007 4:16:23 AM GMT
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Definetly a E3 (Electronics Engineer Extrodinare!)
"I laugh in the face of imposible,... not because i know it all, ... but because I don't know well enough!"