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
watch module ds3231
rf module 433 mhz
display oled по SPI 128x64
accumulator li-ion (from mp3 player)
2 x tact switch
components of termometer:
board digispark attiny85 microusb
termometer dht11 модуль
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)
Step 4: Watch Sketch
sketch is yet raw and need to be modified, but works without bugs.
modes of watch changes by pressing A button
data of t,h, baro and alt saves in EEPROM every minute (contain 60 cells for last hour) and every hour (contain 24 cell for last day)
grafics plots by dots from right to left (from newer to older data). scale of T24 plot can be zoomed by pressing B button
Step 5: Conclusion
this project is still unfinished, and need to be modified
distance of rf connecting is just 4-5m, how to increase this distance??
for power saving wacth must have slipping mode and must waken by pressing button. how to realise it?