motorized drawer

Discussion in 'The Projects Forum' started by estevo, Dec 26, 2012.

  1. estevo

    Thread Starter New Member

    Dec 25, 2012
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    I am looking for a simple as possible circuit for a motorized drawer. The drawer needs to be opened with a push of a button then close when the button is pressed again. I am thinking I may be able to use a servo lever or screw drive plunger to push and pull the drawer so what I need from you experts is a simple circuit to do this maybe including a 555 to control the servo plunger or lever. I have seen the plungers with included circuitry for this but they are too expensive to use in this application.

    I plan on building a lot of these for a application so I can't just tear apart a cd drive or something like that I need to be able to buy all of the parts from a supplier as needed.

    Any help asap will be greatly appriciated because this project may help our small business from going under in this crappy ecnonomy. Thanks in advance
     
  2. John P

    AAC Fanatic!

    Oct 14, 2008
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    I see this is your first posting here, but you've fitted perfectly into the Allaboutcircuits tradition by asking for help without specifying anything useful about what you need. How heavy is the drawer, how far does it have to move, how fast, what are the constraints on mechanism size, power source, potential contamination, safety--and there's sure to be more.

    Please consider your problem not as you see it, with full knowledge of how it fits into your product, but how it's going to appear to a stranger who knows nothing except what you've explained.
     
  3. nerdegutta

    Moderator

    Dec 15, 2009
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    What type of drawer?

    How heavy is it?

    What will it be made out of?

    What will it fit into?

    What is the powersource?

    Specs on the motor?

    The amazing part is the asap thing...
     
  4. MrChips

    Moderator

    Oct 2, 2009
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    What a delightful idea. Use a windshield wiper motor.
     
  5. nerdegutta

    Moderator

    Dec 15, 2009
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    And with the wiper circuit, you have 3-4 open/close settings. And one might be intervals. GREAT!
     
  6. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    Put kksmith in find box for some hints.
     
  7. estevo

    Thread Starter New Member

    Dec 25, 2012
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    I really appreciate your help on this project and please xcuse my lack of information needed. Unfortunately my electronic experience is in audio so I am not familiar with, robotics but I will anwer your questions as best as I can.This drawer will be aprox 6" x 8" and, 2" deep and made of thin guage metal, the amount of travel will be aprox 6" as far as room available for the drawer, motor and power supply, to save room I will probably have to use a rotary servo with linkage. , I am making the complete item so I will design the enclosure around the drawer and power mechanism, the drawer including contents will not weigh over 1 lb. The speed is not criticle but I am thinking 1"to 2" a second . I may have to disassembe a finished item like a wind shield motor mentioned to obtain what I need but if possilble to save time and cost, I would like to buy all of the required parts individually then assemble them. I will also design the power supply around what is required so that is not a problem, I am thinking a 12vdc 1A to 3A. since these servos need a digital signal to make them operate I need help on design of a circuit. If this is still not enough information let me know ai may have to end up hiring an engineer but since we are a small company with shallow pockets I am trying to avoid that expense. Again I appreciate any assistance that can be offered to this project.
     
    Last edited: Dec 26, 2012
  8. MrChips

    Moderator

    Oct 2, 2009
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    Estevo, this is a very doable project and I hope we can collectively find you a working solution right here on AAC.

    I think the biggest problem will be finding the room to mount the motor.
    How many drawers are there on this equipment or cabinet or is it single drawer?
    How much space is there behind the drawer and the back wall or is there space behind the back wall, or on either side of the drawer?

    Here are some options:

    1) Rack and pinion on the side or underneath the drawer
    2) Lead screw underneath the drawer

    I think the electronics is straight forward. You will need two limit switches to sense open and closed positions.
     
  9. estevo

    Thread Starter New Member

    Dec 25, 2012
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    I really appreciate the offer to help and will get back with you on the dimensions.

    Estevo
     
  10. John P

    AAC Fanatic!

    Oct 14, 2008
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    Other options:

    Friction wheel against bottom of drawer.
    Timing belt.
    Various ways of pulling a cord, though I'd call that one a dubious idea.
    Air cylinder (sounds unlikely, but that "designing an Automatic pop-up target using a geared DC motor" project has turned into a pneumatic system).
    Linear motor?
    Rail gun--oops, can't discuss that here. And I don't think it can run both ways.

    Edited to say, you might not need limit switches. If your drawer just moves between end points, you could sense the current and cut the power when the motor stalls.
     
    Last edited: Dec 27, 2012
  11. gootee

    Senior Member

    Apr 24, 2007
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    If you had the room, a lead-screw would be very simple. Imagine a threaded rod, with a nut on it. Imagine the nut is securely attached to the bottom of the drawer and cannot turn, with the leadscrew oriented in the direction the drawer is to move. Turn the leadscrew (threaded rod) and the drawer moves. All you need is a reversible motor, coupled to the leadscrew with a short piece of rubber or plastic tubing. You could probably use an audio-type chipamp or a power opamp to run the motor (LM1875 or LM675 ?).

    You might not want to use the common "allthread" rods from a hardware store, for the leadscrew, although they might work for quite a while (probably use a long "coupling nut", if you do use allthread). But it depends on how the drawer is going to be used, and how much. There are two other main types, called Acme rod and Ball-Screw rod. Acme is a lot cheaper than ball-screw. It has "square" threads. Ball-screw is usually used only when you need very good precision and very little backlash (slop) when reversing. I guess you'll also need a couple of mountable bearings or bushings, to support, and fix in place, the rod, one at the drawer-front end, and probably one for pass-through of the rod, near the motor.
     
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