DIY Hot Beverage Monitor - Using the DS18B20 and Arduino Nano





Introduction: DIY Hot Beverage Monitor - Using the DS18B20 and Arduino Nano

About: Expert in nothing, interested in everything.

My girlfriend always have a problem that she burns her tongue when she taste hot drinks. Then I started thinking, maybe I could create a device that prevents her burning her tongue, so she can drink her tea and it always have the perfect and wanted temperature.

Two things I wanted to learn about in this project was how I could use the temp sensor DS18B20 with Arduino and how I could make a easy battery function with a batterypack on Arduino.

Here is how it works!

Red light - to warm

Green light - prefect

Blue light - not connected

The project may not be something everybody want to make. But I want to show you what I made. Therefore I make my project as an Instructable so you can see my progress and see how I was thinking trough the project.

Check the next step to see how i made it.

Again, sorry for my bad English and I hope you like my project.

Step 1: Parts

Here are the parts i uset to complete this project

9x Small magnets

1x Arduino Nano

1x Batterypack

1x Temp sensor

1x 4,7k resistor


1x Button

3mm steel plate


Acryl plate



Leg pads

Brown paint

Step 2: Designing and Making the Device Housing

The first thing I started with was designing. I designed the device in Google Sketchup. First I started making two circles of wood there one circle was hole on the inside. Outer diameter 10cm, inner diameter 8cm. Thickness of the wood was about 1cm. Then I made a ring like the one wood ring, with hole inseid. Then I stacked these up on each other and got a round box without a bottom. To make a bottom I cut a steel plate to a circle so that it fits with the other circles.

After that I used wood glue and super glue to the layers together except the steel plate.

Step 3: Electrical Parts

This box is really very simple, made with some common electronic parts.

The battery box is an old powerbank I found lying around. I opened the cover and used the battery and circuit board.

I glued 4 RGB light inside the box that will alert about the temperature in the cup.

I add a simple button to turn on the device. It is connected between the battery and the Arduino.

I removed the USB connector on the circuit board for the batterypack and soldered 5v + and - to Arduino pin Vin + and Gnd-.

For easily charged up device, I drilled a hole in the steel plate so that the micro USB port on the circuit board to the battery can stick out there. Then I easily can charge the device with mobile charger. Also drilled a hole to the button.

See wiring diagram.

Step 4: Connect Cup and Device

To communicate with the box I had a big problem figure out a solution. Eventually I found out that magnets were the solution.

To make the cup, I took a cup and drilled a hole in the bottom, then I took a 3 wire temperature sensor and threaded through and glued to the bottom. Then I made 3 circles in different size and soldered the 3 wires from temp sensor to the rings. To get the signals in the cup I mounted 9 magnets. I drilled holes for these on top of the unit. These holes are lain up against the rings on the cup. The one magnet in the middle is + on temp sensor, the 4 magnets in around the middle is - and the 4 outer magnets are the signal. Using food graded hot glue under the cup.

It's hard to explain how I did it but i hope you understand when you see the pictures.

Step 5: Arduino Code

I'm no expert in programming. The code is very simple. It reads the temperature of the cup and based on what the tempertature is use different colour to alert through Arduino and RGB lights.

Blue light means that the cup is not connected. A green light indicates that the beverage is ready to drink. A red light indicates that the beverage is too hot and you have to wait. I myself have the ability to adjust the temperature I want in the program.

Step 6: Last Touch

The last thing I did was to paint device in a brownish paint. To add the bottom plate I glued four nuts inside the device so I could use screws to add the bottom. To the end I only used two because it wasn't space for all four. To get the box steady I put on four chair leg pads.

Hope you liked my project.

Make sure to vote in the contest if you want !


Peder W

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    39 Discussions

    which arduino nano do we need?

    which temp sensor

    1 reply

    You can use this any Arduino Nano just search for it on Ebay.

    The temp sensor is a DS18B20.

    in order to make this plus what was the smaller circuit board? thankyou.

    1 reply

    The smaller circuit board is the battery charger board.

    these are the last things i need to know

    would it be like this

    1 reply

    is this the temp sensor

    also was there any problems with making this project

    and was there anything like this at the time you were making it

    1 reply

    Was alot of problems in this project, but I think i manage to get it working.

    The biggest problems was the space in the device and the temperatur connection from cup to device.

    thank you for telling me this i can start making it for my assignment and i mean for long long are the wires. i meant by how long is each wire from the magnet. sorry if this is not an explanation but this is a brilliant project thank you for making this and sharing it.

    2 replies

    To wires are so long they need to be to connect the magnets to the arduino pins.

    for long long whoops mistake

    p.s.s in step 6 it has the usb and then there is to the left is that the button? it is the third last picture. last but not least how much did the stuff that you bought cost and from where?

    1 reply

    Yes that's a button to turn the device on and off. It's added between the battery and arduino Vin.

    All the wood, steel, battery and plexiglass was something I had lying around. The rest cost maybe around 10$.

    ok um sorry if this is annoying i am making this for a school project and for my mother but anyway did you hitch the wires for the battery and the usb together. how many rings did you need to make. how long did it take and was it aa rechargeable battery's. also how long are the wires and was it singular RGB lights or a band of them?. p.s this is a bloody good project and thanks for showing us.

    1 reply

    Haha, you are not annoying at all! It's fun to see that others want to make this :)

    - Yes, the circuitboard with the micro usb is a chargerboard for the battery. I removed the USB and just connectet it to GND and VIN on the arduino. The battery is 5v 1700mAh. Its not a normal AA battery.

    - I made 4 rings. One metal on the bottom, then a wooden ring, then a plexiglass ring and on the top another wooden ring.

    - It took me about a week doing this project. I did when i had time to do it.

    - How long are the wires? What do you mean?

    - It's singular RGB, four of them.

    could you explain the wiring a bit more precisely where each piece goes

    1 reply

    Have you seen the schematics? I thought I made it very easy for others to understand. If you can ask more precisely what you not understand it would be easier to answer :)

    for instance make a video on it because this is a beut of a piece but the wiring and what type of battery what is the way you make the wood moold?

    1 reply

    Yeah I know the wiring is terrible, but it was so tight that it was hard to get it look nice. And it is also inside the device so no one can see it.

    The battery is a old batterypack I had lying around.

    To make the device housing itself I just mad the rings you can see on the picture, glued them together and did alot of sanding.