Project: Fully Automated Coffee machine

Discussion in 'Modding' started by swamprat, Aug 7, 2006.

  1. swamprat

    swamprat Member

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    Im getting sick of having to walk from my computer to the kitchen to make myself a coffee. I take 1 heaped spoon of nescafe, 3 sugar pills, 1/4 of milk and drink it in 2 mins tops. I have thus decided to make a fully automated coffee machine.
    It must be able to:
    1. Store the water
    2. Boil the water
    3. Store/cool the milk
    4. Add the same amount of water everytime
    5. Add an adustable amount of coffee
    6. Add an adustable amount of milk
    7. Add an adustable number of sugar pills
    8. Stir the coffee
    9. Have a cleaning cycle
    10. Possibly have an easy adaptation for a grinder/ perculator system incase i move on from instant
    11. Run off mains power

    The ultimate aim is for this machine to be operated via a computer connection.
    Ambitious, hell yeah.
    I am designing each portion of the system independently and integrating later on.
    The system may be powered via both a PSU and plug in power. The PSU outputs DC power (or so i was lead to believe) which means that the solenoids i require, i could make myself. Which means that the stroke length and power requried are easily met. The plug in power would be utalised for canabilised components that run off mains power. This could lead to a powerboard being integrated into the system so only 1 external power cord is required.

    Sugar despenser

    [​IMG]

    The solenoid requires a stroke of 3mm with 9.8N of force (900-1000g will trigger the dispenser)
    The despenser is of 3.2 cm diameter in the body, 6.8cm high in the body and the top is 1.2 cm high.
    I am still trying to figure out what can be used for the component that will adjust the pulse to the solenoid so that suffient time is allowed for the return force of the dispenser's top (spring powered i think) to close the solenoid plunger. Suggestions would be welcome

    Milk despenser

    Currently unplaned. I am thinking of having a syringe type system where the starting position of the plunger is what is used to determine the amount of milk dispensed. however this would either require physical interaction or a very complicated solenoid system. For the preset quantities ie sugar, milk and coffee, i think aslong as the settings dont have to be ...set.. for each cup, a bit of tinkering will be acceptable. This is designed as a system for an individual so that settings shouldnt need to be changed frequently.

    The storage of the milk i'm thinking will be via a small portable fridge, of the style seen in dick smith stores. I dread the idea of creating my own cooling mechanism to keep milk below 4 degrees with 30 degree ambients and a requirement for low noise. These small fridges operate off mains power so this connection would be left.

    Cleaning
    The portion of the system exposed to the milk will be the hardest to do because of hygine requirements. This is where the cleaning cycle comes in. The cleaning for the water system simply is to prevent stagnated water so is much easier and the cleaning for the mixing system is just as easy as the boiling water is added directly into there, meaning steralisation is simply a matter of runnign the system without adding milk coffee and sugar. Maybe adding detergent instead.

    Coffee Dispenser

    As yet, no ideas

    Water measure

    This is a very simple component. The water volume does not need to be adjustable so the main water storage tank simply drains into a tube/pipe of the desired volume. The lower end of this pipe is closed by default with a solenoid operated valve/blocker. When the system starts, the upper end closes with a solenoid valve, confining the desired volume of water. The lower value then opens and lets the water drain. Once this has occured, the lower value closes again and the upper valve opens. These can be operated by a single directional solenoid with a spring powered return mechanisim as they will only move from the default position for a very short time.
    ```````````````````````````````````````````````| pipe|
    ie; top valve-default open; spring (unstreached)--------00000-pull solenoid
    (000 = opening, ----- = solid)```````````````````````|pipe |
    closed```````````````````````````spring (streached)--------0000-solenid

    Water tank

    This will be of an as yet undetermined volume. The main feature of this will be a water level sensor (from jaycar) that will operate a main cutoff switch if the water level drops too low and will prevent any coffee being made until the water is refiled.

    Water heater

    This will operate with a canabolised heating element from a kettle. If it is one with an auto cut off, i may incorporate that. The main thing i am considering here is; Should i have a system similar to a perculator, where the boiling water carries itself up a tube (the downfalll of which is that i would be left with water still in the heating system and would have to incorporate a water level cut off for the heating element), should i have a system by which the release valve is pressure operated ie when the pressure ammounts to the level which correspondes to boiling temperature for that volume of water in that volume of space, the valve opens. (the downfall of which is that i must have a container suitable for pressurisation, emergency release values etc) or should i have a system where there is a temperature sensor which opens a valve when 100 degrees is reached (the downfall of which is that i would have to incorporate a temperature sensor and either deal with the problems of pressure aswell or have the heating system open at the top and venting out of the unit)

    Mixer
    This is a straight forward component that may not be utalised in the final system given that i dont ahve a whole lot of problems with spoons.
    The plan is to use one of the magnetic stirring systems. This is a small barmagnet that is coated in ceramic or glass (hygine) inside the mixing container. Spaced off the base of the mixing container is a small motor with a disk supporting 2 rare earth magnets. This spins, creating a rotating magnetic field which causes the bar magnet to spin, mixing hte solution. The solution would then drain out the bottom into the cup

    USEFUL LINKs:
    http://www.wikihow.com/Convert-a-Computer-ATX-Power-Supply-to-a-Lab-Power-Supply
     
    Last edited: Aug 10, 2006
  2. broox

    broox Member

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    if u pull this off you will need a very comfy computer chair!
    all the best & i hope it works!
    :thumbup: :thumbup: :lol:
     
  3. Sphinx2000

    Sphinx2000 Member

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    Great post :D

    Have nfi how to do it tho. :Paranoid:
     
  4. nux

    nux Member

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    Wouldnt it be easier to move the coffee machine to your computer desk?
     
  5. Romen

    Romen Member

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    Having self cleaning cycles would be a pain in the rectum... atleast for the milk...

    An indea for the milk delivery system could be, having a syringe with the plunger operated by a solenoid or something, with preset height. to get milk in side, drill a hole in the syringe so when the plunger is at top/right height, milk is able to enter the chamber, but the plunger will seal the chamber once it starts to inject.

    [​IMG]

    That OR you could just use powdered milk?

    Oh, and make sure you use a rubber gromit around the syringe and the base of the milk container. Have it so you can remove the syringe easyish for cleaning.
     
  6. tobes

    tobes Member

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    For the coffee you could use a rotating disk with a teaspoon (or whatever) sized depression in one side. Above the disk, have a coffee hopper that feeds into the top of this disk. Below have the mixer.

    To add a teaspoon of coffee simply rotate the disk. It fills at the top and empties at the bottom.

    You could also do this for sugar.

    tobes
     
  7. OP
    OP
    swamprat

    swamprat Member

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    romen, thats basically what i was intending. i gues i didnt verbalise it very well. and i cant stand powdered milk so thats out. and the self cleaning cycle is basically a must. cleaning the syrange wont really do it, as all of the piping etc would need to be cleaned aswell

    nuxie, i dont currently have a coffee machine, and a coffee machine that does more than jsut brew coffee is way out of my price range.

    tobes i like the coffee idea.

    i'll draw up some more plans later
     
  8. OP
    OP
    swamprat

    swamprat Member

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    [​IMG]

    I have designed the reservor bit of it. i forsee the power situation is going to be a problem. i'll be gutting a kettle soonish and that will determine how i will be doing the heating of the water
     
  9. newSpeak

    newSpeak Member

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    Why don't you just keep the kettle intact and use it as a combination boiler and reservoir?
     
  10. mr_wrxman

    mr_wrxman Member

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    For a coffee dispenser, you could have a container at the top which flows into a cylinder. Inisde it you could have a spiral (drill looking type thing) similar to the things used to dig a hole in the ground. Attach it to a motor (which spins very slowly) and when it turns, coffee comes out.

    Hard bit is getting the spiral thing of the right size and then determining how much each revolution puts out.

    Sounds like an awesome idea. can't wait to see how it turns out, perhaps you should get a patent =D
     
  11. tobes

    tobes Member

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    For boiling the water you could also use one of the camping/travel type elements that are designed to just go into the cup boil it that way.

    tobes
     
  12. swamp rat

    swamp rat Member

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    newspeak: yes that would work but it woudl be very inefficient and take a long time to boil.

    wrxman- thanks! this would work great i think. i could either have the screw run for a set time and change the rotation speed via a vairable resistor or change the run time.

    tobes - i havent heard of these but all they would be is a kettle heating element bent into a different shape, correct? ..hmm, what do they run off?
     
  13. FantoM_CircuiT

    FantoM_CircuiT Member

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    I think you can buy them as replacment parts from most hardware stores. the ones i have seen look very different to normal kettle elements, in that they are a different shape and also the metal is far thiner. But i gues that would be ok for the ammount of water being boiled.

    something like this

    This will be an awesome project though, if you can figure out the rest of it :)
     
  14. tobes

    tobes Member

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    here is the first link I found to give you an idea of what they are. I am 90% sure that I have also seen ones that run off 12V so you can use them on long drives.

    Tobes
     
  15. swamp rat

    swamp rat Member

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    yeah, that would be suitable but no more so than a kettle element. the kettle element would also heat faster. im not sure that the immersion heaters would boil the water? whcih could cause sanitary issues

    i dont have the orginial file with me here so i'll edit later but i have decided to change my water level switch from a bodgy float and magnet set up to
    http://www.jaycar.com.au/productVie...&pageNumber=&priceMin=&priceMax=&SUBCATID=494

    which is damn well perfect for what i need.

    im off to saint vinnies tonight to look for a kettle
     
  16. shadowman

    shadowman Member

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    For the dispensing of coffee and sugar, what about a cam setup. Have some form of tube with a spring loaded stopper (the valve). Then have a small DC motor with a cam on it, then for every 'turn' of the cam, it pushes the spring loaded stopper in, letting out an amount of 'stuff' (coffee or sugar).

    This could work for the sugar pills your talking about, albeit slightly different. I'd draw a pic in MS paint for you if Work hadn't blocked it (who the hell blocks paint?)

    The cleaning is easy, you just need to run boiling water through the milk carrying parts, dump to a spill tray. I've got a couple of (expensive) PLC's that would be superb for this project. Probably overkill, but it'd be neat :)

    As for the milk, how about this; A head from a post-mix dispensing machine? Mix your milk and water together at the same time, easily adjustable for milk:water ratio, it'd be tops, as long as it can handle boiling water (would just be a matter of using some better piping).

    Lastly, check out eBay. If your in Melbourne, you can pick up something like this. All you'd need to do is interface to the controller, maybe even just the coin mech + buttons.
     
  17. OP
    OP
    swamprat

    swamprat Member

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    not sure about your cam idea, however, im probably just not picturing it correctly.

    PLC's?
    and the prebuilt thing a) where is the fun and b) too expensive

    [​IMG]

    here is my latest redesign. i will do a clear drawing of the electrics later.
    Does anyone know a good way to have 2 circuits so that when 1 is incomplete, the other is complete? This is for the release under the heating area. i want to run it off the same temperatrue switch. i was thinking of having a pull solenoid with a default hole and a spring but then the float switch wouldnt trip. I need the float switch as added secuitry.

    i was thinking something like this
    ````````````````|
    Heating element-0 0 0--Solonoid for release
    ````````````````|
    ```````````````Power
    but i dont know how to implement it
     
    Last edited: Aug 10, 2006
  18. ShadowGeoff

    ShadowGeoff Member

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    [​IMG]

    Only the motor and heating element requires power.

    Control setup could be done with one 'control' relay and two power relays for heater and motor control. Plus the sensors.

    Heater (Pwr Relay) = (On && (LVL||TEMP)) (temp cutout)

    Motor (Pwr Relay) = (On && (TEMP || MOTOR)) (when water hot, activate, stay active)

    On (Contrl, no power contacts) = SWITCH && (On||ACTIVATE)
     
  19. OP
    OP
    swamprat

    swamprat Member

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    hmm, im a bit of a noob at this whole designing stuff thing. (this is my first project). I understand that the red thing depresses the sugar, the outside grey bit turns and is geared into the coffee funnel. however, what do the green and blue bits do? the blue bit seems to be related to the valves but im unsure as to how.

    Is that text ie the &&(Level||TEMP) the standard way of writing circuit explanations ?
     
  20. shadowman

    shadowman Member

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    Almost exactly like I had in mind with the cams, beautiful work :thumbup:
     

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