ATtiny85 Watch

Use a ATtiny85 8pin AVR chip as watch with a alarm LED, a 128x32 i2c oled display and 2 buttons for set hours, minutes and count down (alarm).

Project page

Jochen Peters Krefeld

Features

• optimized for 1MHz (8Mhz needs more power)
• displays the Lipo power in mV (menu mode)
• Button 1: Display on (clock mode) or set hour/minutes
• Button 2: switch through clock, led on, menu mode (set hours), menu mode (set minutes)
• 1/8th of a second: a hour glas
• CPU power down between every cycle of 120ms (with 128Hz clock)
• time accurency: about 2sec in 1hour
• lifetime: above 46h (65mAh Lipo after charging it)
• low battery symbol

Circuit

Vibration alarm

I use a BC108-C . Set Vibration motor + to RAW (3.7 till 4.1V) and V-motor - to the collector, GND to the emitter, LEDPIN to the basic.

...xx..
..x..xxxx
.x..E....x
.x.....B.x
.x..C....x
. xxxxxxx

future steps

• nice circuit / more details
• programming how-to

Images (old, development)

Chassis build with 1:3 silicone (hardware store), food coloring and maize starch (supermarket).

Strange timing and flashing

I have to switch via sh 8MHz.sh skript from 1MHz back to 8MHz, because Arduino IDE
can not flash ATtiny85 in 1MHz mode. After programming I have to switch ATtiny85 back with
the sh 1MHz.sh script.

Thanks to ..

Thanks to Neven Boyanov and the Tinusaur/SSD1306xLED project. (MIT License)
The Tinusaur Project. I modified it to use a
128x32 instead of 128x64 oled display.