One-Wire Temperature collection, publishing to EmonCMS using OmegaOnion

I needed a quick solution to log the temperature of my hot water cylinder at home, had an Omega Onion lying about so used that.

OmegaOnion
OmegaOnion EXP Dock
2 x DS18B20 Sensors, wired together with a 5K7 pull-up resistor

From a factory reset:

• echo "w1-gpio-custom bus0=0,19,0" > /etc/modules.d/55-w1-gpio-custom
• reboot
• Find the names of the sensors, "ls /sys/devices/w1_bus_master1/
• opkg install curl
• opkg install nano
• nano temp.sh

#!/bin/ash

temp1=$(awk -F= '/t=/ {printf "%.03f\n", $2/1000}' /sys/devices/w1_bus_master1/28-000006560975/w1_slave)

temp2=$(awk -F= '/t=/ {printf "%.03f\n", $2/1000}' /sys/devices/w1_bus_master1/28-0000065711e6/w1_slave)

curl --data "data={temp1:$temp1,temp2:$temp2}" "http://192.168.1.129/emoncms/input/post.json?node=55&apikey=xxxxxxxxxxxx"

printf "\n"$temp1"\t"$temp2

• Then all you need is to create a cron job, crontab -e

*/5 * * * * /root/temp.sh >/dev/null