Main idea was taken from Mini-weather-station-with-Attiny85

My idea was to create small portable watch with following features:

- show time and date

- show internal clock temperature and atmospheric preassure (and altitude)

- get rf (433mhz) data of temperature and humidity from small device based on attiny85

- save data of temperature, humidity, preassure and altitude of last 24h and last 60 min.

-show graphics of temperature, humidity, preassure and altitude of last 24h and last 60 min.

Step 1: Components and Wiring

components of watch

Arduino nano

watch module ds3231

rf module 433 mhz

barometer bmp180

display oled по SPI 128x64

accumulator li-ion (from mp3 player)

2 x tact switch

on/off switch

components of termometer:

board digispark attiny85 microusb

termometer dht11 модуль

tranceiver 433mhz.

Step 2: Compacting Watch

elements of watch was compact wired and fixed, then plased into fiberglass box

Step 3: Wireless Termometer

power of board was 2x 18650, that gives 7,4v to the board and rf module. power can be much smaller? for example 2x tablet battery. i used usual antenna ~18,5 cm

instead of dht 11 you can use dht22 for more accurate values. you can use other sensors that canconnect with digispark (note that sketch must be less 6kb fo attuny85 !)

sketch is pretty simple and based on Manchester.h library (virtualWire library too heavy for attuny85)

for booting sketch into digispark attiny85 you need special arduino IDE (for example Digispark-Arduino-1.0.4)