Making hot cocoa using arduino

Projects General Guidance
1

I would like to make a hot cocoa vending machine with Arduino. I am stuck on how to heat up the water in a safe and efficient way. I need the water to be decently hot but not too hot. I have not started making the design and would just like some guidance in heating up some water.

Thanks!

2

When I was younger I had a heater that ran from the wall plug (110VAC) to heat 1 cup of water for a cup of soup or the like. You could use something like that and control with a relay.

A DS18B20 temperature sensor to monitor the heat is easy to interface.

3

I too was young before I got old.

But my little immersion heater was no 300 watts.

https://www.amazon.com/Instant-Immersion-Electric-Portable-Reheater/dp/B01M0Q84BR/ref=asc_df_B01M0Q84BR

a7

1 Like
4

That's the usual way. Some young people think they start as old and experienced telling helpers "how to". Not this OP!.

5

I think we’re all in agreement this is two different problems.
Heating / mixing / dispensing the drink, followed by cleaning the apparatus - and a separate Arduino controller.

Sort out the mechanical/physical prototypes, then start on the controller

Both can be designed separately,.. the interface is trivial.

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6

The wife says I was never young.
:older_man:

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7

You might find some inspiration here:

Hot Cocoa 3000: Arduino-Powered Hot Beverage Maker

8

Oops. Mature from the beginning then?

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9

Haha, someone nearby here would say

    old != mature

a7

10

Sounds like are someones are made from the same rib.

1 Like
11

Nice solution, but confused on the backlash here. Is there any backlash? Confused on what Railroader and Larry is saying. Would it work? I imagine using the temp sensor and then when it is hot enough dispensing the drink. I could maybe drill a hole in my cup and then cover it with something, but then take the cover away and dispense. Any thoughts?

Thanks for the activity!

12

This might be a good application for Peltier diodes. They do a better job of heating then cooling.

13

That might work!

Do you have a link to a one you recommend and would I have to water proof it?

Thanks!

14

Is this for the public ?

You need to worry about worst case scenarios i.e. can the water heating container blow up, can someone be burned.

How is it going to be cleaned/flushed ?

How will the liquid be metered ?

Milk or water ?

2 Likes
15

This is not public. Think of it as an at-home coffee maker. I think I will manually clean it every 5 days or so. I plan to have a big jug of water that will dispense the right amount by having a hole in the bottom uncover for the exact right amount of time. I plan to use water, as I am lactose-intolerant and heating milk I think would be much harder.

Thanks

16

IMG_2218
IMG_22181453×1273 212 KB

  • Do you know what a relay is ?

  • Maybe make it simple and just use the Arduino as a timer the can turn the unit on/off/warm and alarm when time is up. :thinking:

17

I think that could work, but I would still like to have a a vending machine feel. Also, I do know what a relay is but how would I wire that up to a 2/3-pin wall plug? Maybe I could wire up the tea heater with a relay and turn it off when it gets the right temp?

Thanks!

18

You can use resistors or power semiconductors as heaters, they work very well. You can look for cooling, then reverse the power to the diode. There is a lot out there.

19

Peristaltic pumps can be used to meter the liquid.

Maybe one pump to fill with water, second pump to meter in cocoa, third pump to fill your cup.

:thinking:

IMG_2219
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Example:

20

How would I use a resistor to heat the water? Could you provide a video or example?

Thanks