NAME

MyDHT - Interact with the Raspberry Pi DHT sensor in my grow room

VERSION

This documentation refers to version 1.

SYNOPSIS

Initialize a new database and take a measurement:

use strict;
use MyDHT;
my $dht = MyDHT->new();
$dht->initialize_database;
$dht->measure;

Take a new measurement:

use strict;
use MyDHT;
my $dht = MyDHT->new();
$dht->measure;

Generate plots and a web page:

use strict;
use MyDHT;
my $dht = MyDHT->new();
$dht->plot("day");
$dht->plot("week");
$dht->page;

DESCRIPTION

This manages the interaction via ssh with a DHT sensor on a Raspberry Pi which sits in the grow space in my garage. It fetches the data via an ssh call, inserts the data into an SQLite database, and generates plots and a web page based on the accumulated data.

Plots are made with gnuplot abd Graphics::GnuplotIF. The gnuplot scritps and the web page are made using Text::Template. Database management is via DBI, of course.

Everythings is placed in $HOME/.mydht and is organized for easy synchonization with AWS via awscli.

See config/plants.json for a list of the plants in my grow room. "Herbs, not herb!"

ATTRIBUTES

folder ($HOME/.mydht)

Location of files.
dbfile (dht.db)

Name of database file.
datetime

The DateTime object with now() for the beginning of the instance of the script.
logfile (old.log)

Data used to initialize the first database.
data (dht.scratch)

A scratch file used to make the plots.
table (TempHum)

The name of the table in the database.
t1

The temperature reading on the DHT sensor.
hum

The humidity reading on the DHT sensor.
t2

The temperature reading on the analog sensor.
now

The end point of the plot as an ISO8601 date/time string.
then

The beginning point of the plot as an ISO8601 date/time string.
ymin, ymax

The range of the temperature axis in the plots.
y2min, y2max

The range of the relative humidity axis in the plots.
span

A text string indicating the length of the plot, used in the title of the plot.
file

The name of the output PNG file.

METHODS

initialize_database()

Start a new database, inserting the values from old.log as the first values.
```
  $self->initialize_database;
```
measure()

Make a measurement and insert the results into the database.
```
  $self->measure;
```
probe()

Grab the temperature and humidity data from the Raspberry Pi via ssh.
```
  my $text = $self->probe;
```
parse()

Parse the text returned from the ssh call and load the t1, hum, and t2 attributes.
fetch_array()

Get a named array from the SQLite database with all data since $beginning, where $beginning is an ISO8601 datetime string.
```
  my $array_reference = fetch($which, $beginning);
```
plot()

Generate a PNG plot of the DHT data for the last day, week, or month. The PNG file will be written to $self->folder.
```
  $self->plot($timespan);
```
page()

Generate an HTML plot of the DHT data. The HTML file will be written to $self->folder.
```
  $self->page;
```

DEPENDENCIES

BUGS AND LIMITATIONS

Well, still figuring that out ...

AUTHOR

Bruce Ravel (http://bruceravel.github.io/home)

http://bruceravel.github.io/demeter/

LICENCE AND COPYRIGHT

This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See perlgpl.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

bruceravel / DHT