Need some ideas on a circuit.

Discussion in 'General Electronics Chat' started by Kip, Jan 29, 2013.

  1. Kip

    Thread Starter New Member

    Jan 29, 2013
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    0
    Good Day,

    My wife put on my honey do list a automatic trashcan in and out device.

    Basically a trashcan on a base plate with linear rails that comes in and out of the cabinet automatically. Using a capacitive sensor, maybe a kick plate switch, she waves her hands in front of the sensor or kicks the plate sensor, the cabinet door opens and a motor drives the trashcan out of the cabinets, and then pulls it back in. I was just unsure of the direction to go about it. I was thinking a DC motor for ease of changing the directions with some limit switches. maybe a pot for speed control. maybe a good place to get such motors, controls, etc. recommended sizes , etc.. I just have not played with many motors outside of high end RC cars. Any input would be greatly appreciated.

    Thank you so much..

    Kip
     
  2. russ_hensel

    Well-Known Member

    Jan 11, 2009
    818
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    Microcontroller -- arduino
    Motor controller, possibly an arduino shield
    Op amps for sensor signal conditioning
     
  3. toffee_pie

    Active Member

    Oct 31, 2009
    162
    7
    wtf........
     
  4. ScottWang

    Moderator

    Aug 23, 2012
    4,853
    767
    How about the size of trashcan?

    Do the capacitive sensors as this?

    That is one kind of the proximity switch, you should care about the measuring ranges of the sensor.

    Probably they has NPN OC and PNP OC type, if you want to buy it, then you have to look the details.
     
  5. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    I would use a set of IR LED and Phototransistor receiver in parallel with a small divider between them so the phototransistor only sees reflected LED light. Set them above the door (tight under the counter top) then she can wave her foot or hand to cause it to activate.

    The easier option that most families use, however, is a voice activated system - the wife usually yells "get off the couch and take out the garbage". The sensors respond faster with higher pitched, shrill voices from the transmitter.
     
  6. ramancini8

    Member

    Jul 18, 2012
    442
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    Two limit switches and two PBs coupled with a dc motor geared to two tracks and door opener. Push out PB, door opens, and can comes out until limit switch stops it. Push in PB can goes in, door closes, and limit switch kills action. Unless your wife is habdicapped this is a lot of work for nothing.
     
  7. Kip

    Thread Starter New Member

    Jan 29, 2013
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    Thank you guys so much for the great responses.

    I just love seeing the ideas flow. Yes it is a lot of trouble for a trash can, but my wife is a gourmet cook and is always in that kitchen making great stuff for our family. She does not like having to touch the trash can while she is cooking. It’s the small efficient details like this one that make a professional kitchen run smooth and with great results.
     
  8. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    Would you feel comfortable programming an IC to help with this task? Many microcontrollers now have a "touch" input, which is just a capacitive pad for input.

    If you want to build this using only relays and limit switches, that can be done as well.

    How far does the can need to slide in/out? What will the maximum weight of the can be?

    The "hardest" part of this will be in the mechanical area. Everything from air cylinders to a large rack and pinion could be used. The important part in all of them is that the rail(s) holding the can are rigid enough to not flex/bend/break when extended with a 50lb load on the unsupported end.

    Have you had any plans for that? Keep in mind that most will require that you have same room behind the can as it will extend out, due to rails retracting. Exceptions are using something like sliding drawer rails that collapse on themselves when retracting (they aren't very strong, though).
     
  9. Kip

    Thread Starter New Member

    Jan 29, 2013
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    Yes I have considered the mechanical aspects of it. I already have the base built using HD Linear rails. (Very strong) I was just looking for a DC motor setup with some torque and speed control.

    Thanks for your input.. Always appereciated.
     
  10. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    Were you looking at a rack and pinion type system that will work with the rails you have currently? Have you located a long enough toothed rack?

    If you have a pull scale, how much force does it take if you fill it half full of unopened soup/sauce cans? That might give a good idea of max load.

    A PICAXE is simple to use and can drive an H-Bridge, it also has touch inputs. The other common choice is Arduino, but that may be overkill.
     
    Last edited: Jan 29, 2013
  11. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    You could mount the tracks on an incline so the can slides out by gravity when triggered (Released), then pulled back by a motor with cable on a spool. That way, the retractable drawer sliders might work for you without having too much space behind the can for the sliding frame.
     
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