TeaBot (Bitter tea? Never again!)

TeaBot (Bitter tea? Never again!)

Imagine this situation: You prepare a cup of tea and look forward to drinking it. Then the phone rings or some other distraction leads you to forget the tea bag in the cup. That’s bitter and so is the tea. All the looking forward to a nice cup of tea turned into bitterness.

These are the kind of situations where a little bit of automation would help. And there is arduino. That got us thinking.

Core Ideas

Let’s build something with Arduino that removes the tea bag in time. But what time? It differs from tea to tea. So the time has to be easily adjustable.

  • When does the time start? Well, when the hot water meets the tea bag. Some sensing would be very helpful there, as there is no reason to start manually.
  • How does it remove the tea bag? It has to be something mechanical. Servos (known from RC-models) are easy to control with an Arduino.
  • If we can lift the tea bag out of a cup, we could lower it in there, too. This would be good to keep the tea bag in motion. Motion would result in a shorter time needed to make the tea. But do we want that? Really? On most tea bags the suggested draw time is printed on. If you speed up the process (by moving the tea bag all the time) all those suggestions would be worthless. Bottom line: Let’s Relax. We don’t keep the tea bag moving.
  • When two people drink tea together, chances are they have different tastes. So the system should be able to make two cups of tea at the same time, but with different drew times.

The result: TeaBot in action

How we did it


The trunk is fastened by a M5x20 screw from below. Also you see the 4 transparent feet in the corners of the base board. From above you see the LCD mounted with M3x20 screws and 3x10 distance rolls. Also good to see: the pull-up resistors are soldered to both sides of the switches.

Hardware (approx. 150..200 € in total)

  • 1 x Arduino Leonardo w/o Header
  • 1 x TimesSquareShield-Bausatz
  • 2 x Servo
  • 1 x LCD 20×4 Seriell
  • 2 x Temperatur-Sensor LM35DX (TO 92)
  • 2 x Servo-Arm (Plastik 10x10x120mm mit Bohrung und Einschnitt)
  • 2 x Holzschraube 2,9×12
  • 1 x Aluminium Vierkantprofil 20x20x250mm
  • 1 x Plexiglas Frontplatte 200x120x3mm
  • 1 x Plexiglas Rueckplatte 120x80x3mm
  • 2 x Abstandsbolzen M4 x 10 innen/aussen
  • 2 x Abstandsbolzen M4 x 20 innen/aussen
  • 4 x Abstandsbolzen M4 x 40 innen/aussen
  • 8 x Linsenkopfschraube M4 x 8
  • 1 x Senkkopfschraube M5 x 20
  • 1 x Frühstücksbrettchen
  • 4 x Inbusschraube M3 x 10
  • 4 x Inbusschraube M3 x 20
  • 8 x Mutter M3
  • 2 x Kipptaster (ein) / aus / (ein)
  • 1 x Kippschalter ein / aus
  • 4 x Widerstand 10 kOhm
  • 1 x Miniaturlautsprecher
  • 1 x Widerstand 470 Ohm
  • 1 x NPN-Transistor BC 546 (TO-92)

Software (free)