raspi_gauge

http access

copy everything under www/ to root folder of your webserver (php has to be enabled), default for raspberry /var/www/html/

there is no security settings to make it easier to read and understand

index.php

start page for browser access loads a gauge and history diagramm (google charts)

api.php

data for it will be loaded as json

data will be read from data access files described below

data access

start python readdata.py

this uses a lib mq.py which is form:

adapted from http://sandboxelectronics.com/?p=165

adapted form https://github.com/tutRPi/Raspberry-Pi-Gas-Sensor-MQ

this will read the start value from ADC and set this as "fresh air" value

this will write data (see file for more details) every 0.5 sec to

smbus_A0.current
smbus_A0.ppb
smbus_A0.ugpm3
smbus_A0.csv

and to the console

MQ-131 Module

since most board do not come with a datasheet/description this is what i used:

data sheet for the heart piece: https://aqicn.org/air/view/sensor/spec/o3.winsen-mq131.pdf

    VCC
     |
    +++
    | | RS
    +++
     |
     +------- AOUTDC
     |
    +++
    | | RL (My board used 1kOhm)
    +++
     O
     |
    GND

Raspberry ADC MQ-131 Module

if you have questions or ideas: subbamaggus@gmx.de