Jocasta

Library to extract data from serial devices and send it various services.

jocasta is used to read JSON output from a serially attached device and relay it to a another service. For example a database or a local csv file.

Example Arduino code can be found here Sensors_Basic. This is a simple sketch designed to read data from a number of cheap available sensors and return the readings over USB serial as a JSON string.

Quick Start

Installation

pip install jocasta or use sudo to install system wide.

Config File (Optional)

Create a directory in your home directory to store the config file.

cd ~
mkdir .config
cd .config

Create a file called jocasta_config.ini and copy and paste the following into the depending on which services you want.

[csv_file]
path = /tmp/sensor_data.csv

[file_system]
file_name = /tmp/sensor_data.json

[influxdb]
host = 192.168.1.100
port = 8086
password = admin
username = admin
database = greenhouses

[io_adafruit]
username = your_username
key = your_key
# change to match your configured feeds on https://io.adafruit.com
feeds = office.office-temperature,office.office-light,office.office-humidity
# field names in your JSON payload from your sensor
measurements = temperature,light,humidity

[temperature_ranges]
maximum = 55.0
minimum = -10.0

The last section temperature_ranges is a range you add to ensure if your reading called temperature is outside of the values stated it will be ignored. This was added specifically as the ds18b20 sensor can report very large or small numbers when reporting an issue.

Running

Start jocasta by add the path of your serial device. This path can be found from looking in rhe /dev directory on both OSX and Linux.

OSX

The USB device will typically be locate in /dev with a name that starts tty.

$ jocasta -p /dev/tty.usbserial-14230
╒═════════════╤══════════╤══════════╤══════════╤════════╕
│ Temperature │ Location │ Moisture │ Humidity │ Light  │
├─────────────┼──────────┼──────────┼──────────┼────────┤
│ 23.2        │ office   │ 568      │ 61.2     │ 5800.0 │
╘═════════════╧══════════╧══════════╧══════════╧════════╛

Raspberry Pi / Linux

The USB device will typically be locate in /dev with a name that starts ttyUSB

$ jocasta -p /dev/ttyUSB0
╒═════════════╤══════════╤══════════╤══════════╤════════╕
│ Temperature │ Location │ Moisture │ Humidity │ Light  │
├─────────────┼──────────┼──────────┼──────────┼────────┤
│ 23.2        │ office   │ 568      │ 61.2     │ 5800.0 │
╘═════════════╧══════════╧══════════╧══════════╧════════╛

Running

A config file can supplied to the command line call using -c:

$ jocasta -p /dev/tty.usbserial-14230 -c /path/to/config.ini

Supported Services

Services and things Jocasta can send data to.

Adafruit IO - https://io.adafruit.com

Adafruit's beta IoT hosted application.

Config

[io_adafruit]
username = username
key = key
feeds = temperature,light,humidity
measurements = temperature,light,humidity

CSV File

Outputs as csv to a file on disk. This is handy for other applications to access the data.

Config

[csv_file]
path = /tmp/sensor_data.csv

File System

Outputs json to a file on disk. This is handy for other applications to access the data. New readings are appended to the file.

Config

[file_system]
file_name = /tmp/sensor_data.json

InfluxDB - https://www.influxdata.com

Config

Add the following to your jocasta-config.ini file, making sure you update the values to match your InfluxDB server.

[influxdb]
host = 192.168.1.100
port = 8086
password = admin
username = admin
database = greenhouses