Guido Had a Strong Aversion to Overbrewed Oolong

June 27, 2005
For Guido Vollmar's complete instructions on how to build your automatic tea timer, click here . To view pictures and a schematic diagram of the tea timer, click here .

In search of the perfect cuppa, Guido engineered this simple, battery-operated tea timer with a built-in LED display. Just fix a tea-bag on the mechanism's extension arm, place a cup of hot water beneath it, and push a button according to the desired brew time. The microcontroller-operated, 5V circuit provides a servo motor with control pulses to lower and raise the extension arm. The brew process can be interrupted via a stop button, while the power supply is switched off automatically via FET.

Tea Timer Parts List
Amt Part Description Allied Part #
1 9V Battery 737-0530
2 100 nF Capacitor 881-5228
1 330 pF Capacitor 881-5182
1 10 muF Capacitor 852-7072
1 470 muF Capacitor 852-6592
2 BAV 100 Diode 431-0452
1 400 mA Fuse 740-5209
2 Fuse Clips 846-6062
1 LM317T 288-1251
1 Yellow LED 782-0040
1 NC Slider 870-9934
4 NO Push Button 948-7199
1 Transistor BC846 263-0418
1 Si 9430DY MOSFET 307-1057
Additional parts required: IC1 PIC: 16C54; Servo motor like used in RC-toys; Old cookie box or similar package as housing; Short piece of wood for extension arm; Screws for mounting servo and protoboard; Assorted resistors (see detailed parts list online); Protoboard; Battery holder

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