Hi, I have a project wherein I am using a capacitive proximity sensor to sense whether or not there is a plastic in front of the sensor. The sensor is loaded in a car and if the capacitive proximity sensor senses a plastic is there a way like coding the Arduino so that the sensor sends a "there is a plastic in front" signal back the Arduino and make the car do something else?
I could easily code the car to do something else if the capacitive proximity sensor activates, but I only want it to activate or send back a signal if it senses plastic.
Make a little sketch that only reads and displays the value of the sensor. Then You will know how it is functioning. Next step is to install the proper libes of code in the car sketch.
missdrew:
Does this sensor send back anything to say what it senses?
Nope. I just need the capacitive sensor to send some sort of signal even if it is just a number.
I've never tested the sensor to be honest, but can I make it so that the capacitive sensor only activates and send a signal back to the Arduino when it senses plastics?
Edit: Base on my searches, I cannot find anything where it tells that capacitive sensors can easily differentiate plastics from other non-metallic objects.
Railroader:
Make a little sketch that only reads and displays the value of the sensor. Then You will know how it is functioning. Next step is to install the proper libes of code in the car sketch.
Base on my searches, capacitive sensors detect different non-metallic objects and sends a signal that it detected a non-metallic object.
Can I code the sensor or the Arduino so that the car will only do something (like turn around twice) when the sensor detects plastic and if it detects other non-metallic object, it will do nothing?
Can You Google on that JLC.... for its data sheet? I'm fiddling with a mobile for the moment.....
I'm afraid the sensor needs more than 5 volt to work.Vdd of 12 uo to 36 volt.
It looks like similar to an inductive sensor I use.
When it is activated it outputs Vdd. When it is not activted it will be leeking some signal also.
Railroader:
Can You Google on that JLC.... for its data sheet? I'm fiddling with a mobile for the moment.....
I'm afraid the sensor needs more than 5 volt to work.Vdd of 12 uo to 36 volt.
It looks like similar to an inductive sensor I use.
When it is activated it outputs Vdd. When it is not activted it will be leeking some signal also.
If you mean JLC International, it says no results found...
Railroader:
No. The entire designation of the sensor told in bold characters.
The data sheet just gives the various physical dimensions of available devices. There are loads of reports of people using the device with their 3-D printers. They indicate there is no QC in the device manufacturing, so the sellers are likely selling the "drop-outs" from factory testing. Each device also seems to need calibration for distance.
Paul
Uhm ... personally, i doubt it can work with plastic (or at least, most of the plastics) ... this chart says standard detection object iron ... for all the models of that family ...
Anyway, a capacitive sensor usually detect the variation of capacitance ... if the plastic you want to detect is totally insulant (and then does not alter the capacity of the head), how can be detected ? ... have you tried this point ?
I do not think this is possible if your goal is to detect any kind of plastic and differentiate it from any other type of material. Plastics vary hugely in just about every imaginable property. You might have better luck if you're trying to detect a very specific form but even then it's not straightforward. Do you have any information about the type of plastic you're trying to detect? Is it colored, transparent, opaque ....?
S.
srturner:
I do not think this is possible if your goal is to detect any kind of plastic and differentiate it from any other type of material. Plastics vary hugely in just about every imaginable property. You might have better luck if you're trying to detect a very specific form but even then it's not straightforward. Do you have any information about the type of plastic you're trying to detect? Is it colored, transparent, opaque ....?
S.
I am trying to make it so that it only detects LDPE's and aluminum wrappers.
You can probably detect easily aluminum (not just wrapper) cause being conductive, it alter the capacity of the proximity head (as any other metal) ... but about LDPE alone, i think not ...
And also, probably not "just" aluminum ... using a discrimination sensor (like the ones in coins mechanisms, as example) you can easily detect from magnetic and non-magnetic metals, but discriminate from different non-magnetic metals is a bit more difficult ...
Etemenanki:
You can probably detect easily aluminum (not just wrapper) cause being conductive, it alter the capacity of the proximity head (as any other metal) ... but about LDPE alone, i think not ...
And also, probably not "just" aluminum ... using a discrimination sensor (like the ones in coins mechanisms, as example) you can easily detect from magnetic and non-magnetic metals, but discriminate from different non-magnetic metals is a bit more difficult ...
I seem to find the discrimination sensor you're talking about that I could use (my searches only show those coin mechanisms)...
Can capacitive sensors give a numerical signal depending on what they detect and send that signal to the Arduino? For example for plastics they give the value of 54 which is sent to the Arduino, for wood they give a value of 50 which is sent to the Arduino, etc.
And if they can, can you program the capacitive sensor so that it only detects a certain value? If also yes, can you send a code example? Thanks!
No, i don't think so ... capacitive sensors just detect the proximity of an object for the variation of the capacitance, this depend both from the mass of the object, it's conductivity (or better said, dielectric constant), and the distance from the sensor ... as far as i know, there is no way for have specific values for specific substances just using capacitive sensors ... maybe using an array of specific sensors, mixed types (capacitive, inductive, optic, ultrasonic, conductimeters, and so on) with different characteristics, and using material samples with identical shape and distances can be possible to have some generic indications, but there are too much materials that have almost identical (or very similar) dielectric constants ...
I mean, you can easily sense the level of water inside a plastic tank with a capacitive sensor, cause the dielectric of water is 80, compared with 3 to 6 of the most of the plastics, so the plastic will not become detected opposite to water ... but, still as example, polyamide, sand, rubber, plexiglas, oiled paper, wood laminate, glass, mica, polystirene, porcelain, celluloid, and a lot of others, have dielectric constants from 3 to 6, almost impossible to discriminate between them with a capacitive sensor alone ...
Also, most of those capacitive sensors are just ON-OFF types ... some of them can have a sensitivity regulation, but just for set the triggering distance ...
Etemenanki:
No, i don't think so ... capacitive sensors just detect the proximity of an object for the variation of the capacitance, this depend both from the mass of the object, it's conductivity (or better said, dielectric constant), and the distance from the sensor ... as far as i know, there is no way for have specific values for specific substances just using capacitive sensors ... maybe using an array of specific sensors, mixed types (capacitive, inductive, optic, ultrasonic, conductimeters, and so on) with different characteristics, and using material samples with identical shape and distances can be possible to have some generic indications, but there are too much materials that have almost identical (or very similar) dielectric constants ...
I mean, you can easily sense the level of water inside a plastic tank with a capacitive sensor, cause the dielectric of water is 80, compared with 3 to 6 of the most of the plastics, so the plastic will not become detected opposite to water ... but, still as example, polyamide, sand, rubber, plexiglas, oiled paper, wood laminate, glass, mica, polystirene, porcelain, celluloid, and a lot of others, have dielectric constants from 3 to 6, almost impossible to discriminate between them with a capacitive sensor alone ...
Also, most of those capacitive sensors are just ON-OFF types ... some of them can have a sensitivity regulation, but just for set the triggering distance ...
Railroader:
You likely ask for a miracle sensor not invented yet. Search among space scientists tools for spectroscopic analysis of materials from space.
So... there is still no straightforward sensor that can detect plastics and aluminum wrapper (i.e. potato chip bag) only and accurately?
Aluminium can be detected but plastic.... It looks difficult using that type of sensor. Look at the theory of a capacitor. 2 electrodes, large plates with a well defined space between them, and a dielectric medium, Your test object, between the electrodes.