Python pi ultrasonic distance sensor used as tank sensor to output levels to a json feed
{"percentage": 76.3988548810431, "gals": 190.99713720260775, "name": "OilSensor", "cm": 37.83, "in": 14.893700787401574}
This is a python script to output the distance of a tank sensor to tank gallons left and percentage of tank full. I am using the script to display the results on my magic mirror.
Connect sensor to your pi
To install you must install apache and php on your pi from your home directory ~/pi run
git clone https://github.com/freshfitz/OilSensor
To install apache and php run
sudo apt install apache2 -y
sudo apt install php libapache2-mod-php -y
this script will use index.php to display the json so first lets remove the default index.html
rm -rf /var/www/html/index.html
#Create index.php
touch /var/www/html/index.php
#allow index.php writeable from the python script
chown -R pi:pi /var/www/html/index.php
chmod 777 /var/www/html/index.php
#If you have your sensor connected to your pi run
python ~/OilSensor/sensor.py
You should get an output of
pi@oilsensor:~ $ python ~/oilsensor/sensor.py
Waiting for sensor to settle
Calculating distance
Distance: 37.46 cm
Distance: 14.7480314961 in
Gallons: 192.220837567 US
Percentage: 76.8883350267 %
if you browse to your pi's ip address you should get http://ip-of-pi
{"percentage": 76.3988548810431, "gals": 190.99713720260775, "name": "OilSensor", "cm": 37.83, "in": 14.893700787401574}
Look at the top lines of sensor.py you will have to adjust the distances for your setup and the tank size for your setup
You can now use anything you want to read this json format, for example I have it displaying on my magicmirror using MMM-Json-feed https://github.com/amcolash/MMM-json-feed
To update the data I have a cron job running, simply use
crontab -e
*/5 * * * * python ~/oilsensor/sensor.py
this will run the script every 5 min and update the index.php file