LittleTea: Robotic Tea Brewing

This project was made as part of the June Instructables Build Night with littleBits at the Taipei Hackerspace.

Whenever I'm trying to brew some tasty tea (and that happens quite often) I always miss the right amount of time needed for the brew. Talking to someone, reading a book, watching a bit of YouTube, browsing Instructables while I'm waiting, and suddenly the 5 minutes becomes 15, and my tea is not as good as it could have been.

Enter littleTea - it is a little Bits controlled robotic tea timer that takes care of your timing. It removes the teabag from the cup after the correct amount of time has passed, and let you know that you are ready to enjoy your beverage...

Required parts for the project:

• littleBits:
  • Arduino-at-Heart module
  • Servo module
  • Buzzer module
  • Power module + wall-plug (probably battery would work as well)
  • Button module
  • Wire module x2
• Cardboard
• Stick
• Rubber bands
• Craft knife, pen
• Teabag and teacup

The whole project can be assembled in less than 10 minutes. The programming part took the longest time in the entire development.

Cardboard was used as an easy way to mount the servo motor, which will use a stick as a lever to lower the teabag and raise later.

The cardboard has to stand pretty solid. Cut two vertical lines in a tall (~20-25cm?) piece of cardboard. Cut two other pieces that fit in there. The original slots should be narrow enough that the fitting pieces cannot wiggle much (at all).

Higher up on the board cut a suitable square slot to fit the servo. It should be very snug as well! Can cut it by drawing the outline of the servo on the board, or directly cutting around the servo held at the board (just be careful not to cut the servo's wires). Unplug the servo from the littleBits module, that way it fits through the hole, and plug it back later.

Find a good stick (e.g. the type used for ice cream, but preferably an used one!) that will be the lever. Fasten it on the servo some way. Here I used rubber bands, but can be anything else as well that works for you. Near the top (but not at the total top) of the stick make a little wedge. That's where the tea bag's string will fit, and it is used to keep it sliding down the stick as it is raised.

One thing to keep in mind: mount the stick that way that it stands horizontally and has some way to move both up and down a bit from it's horizontal position!

Now almost everything is ready. Can add some decoration to the cardboard - here I was very minimalistic.

When mounting the tea bag, make a little loop and tie it. That way the bag won't accidentally fall off.

Connections needed for the modules to match the code mentioned above:

• power to one of the analog input pins of the Arduino module
• button to the d0 (in) channel
• buzzer to the d1 (out)
• servo to the d5 (out), can use an extension cord to move the module away from the cup (and potential water). Set output to "analog" mode
• extension cord from d9 to the input side of the button (to power the button correctly)

The source code for the Arduino module is in the imrehg/littleTea repository on Github. The servo values of the off (not brewing) and on (brewing) case are hardcoded in there, and you will need to adjust those values (based on trial and error) to have a good setup. The tea bag should be completely out of the tea cup originally. When lowered it should submerge.

For flashing, use the Arduino Leonardo settings (the littleBits Arduino module is equivalent of that).

Now ready for some tea!

The default setting is 5 minutes brewing time. After that the servo will carefully lift the tea bag out of the cup and sound the buzzer.

To see - with a shorter time setting - the behaviour of the setup, check out the video above.

Cheers, have a happy tea time!