Arduino YUN ViewBox

An Arduino Yun with an 20 chars x 4 lines I2C LCD screen (with PCF8574 chip).

The viewbox display temperature, pressure from a garden weather station, it display also the level of "vigilance meteo" (weather alert french system). All this informations are available on a local MQTT broker.

A script check regulary the number of unread mail on an IMAP server. The result is also display on the panel.

Every data process and formating is doing by Python script. Screen content is send on a 80 bytes bloc with bridge/datastore. The arduino skecth read datastore value and send it to the LCD I2C interface.

Files

• yun.py format data from MQTT broker send it to datastore.
• email.py check unread mail number on IMAP server send it to datastore.
• Yun_LCD_I2C.ino is ATmega 32U4 sketch, do datastore to LCD transfer.

Requirements

Python

MQTT lib

Add paho MQTT to your Python lib (test with 0.9 version):

sudo pip install paho-mqtt

json lib

Usage of json Python library is buggy on Yun (conflict with bridge json lib). More details here arduino/YunBridge#18.

To fix this problem:

opkg update
opkg upgrade cpu-mcu-bridge

System setup

mkdir /root/bin/
cp yun.py /root/bin/
cp email.py /root/bin/

email.py call by cron every 5 mins

root@Arduino:~/bin# cat /etc/crontabs/root
#format [min] [hour] [day of month] [month] [day of week] [program to be run]
# add this to /etc/crontabs/root
*/5 * * * * /usr/bin/python /root/bin/email.py