[Raspberry Pi] A simple bot in Ruby that uses RPi::GPIO to check a pin on a Raspberry PI with a moisture sensor on it to see if it needs watering. #pi

crontab

45 11 * * 1-5 /bin/bash -c 'export PATH=~/.rbenv/shims:~/.rbenv/bin:"$PATH"; cd /home/pi/app/plant/; ruby thirsty.rb'

Gemfile

source 'https://rubygems.org'

gem 'rpi_gpio', '~> 0.3.3'
gem 'slack-ruby-client', '~> 0.10.0'

thirsty.rb

#
# Run this file using CRON
#

require 'rubygems'
require 'logger'
require 'bundler/setup'

Bundler.require(:default)

Slack.configure do |config|
  config.token = 'xxxxxxxxxxxxxxxxxxxxxx'
end

class Thirsty
  PIN_NUM=17
  SLACK_CHANNEL='#slack-channel'

  def initialize
    $stdout.sync = true
    RPi::GPIO.set_numbering :bcm
    RPi::GPIO.setup(PIN_NUM, as: :input)
    @slack = Slack::Web::Client.new
    @logger = Logger.new($stdout)
  end

  def self.run!
    new.check_plant
  end

  def check_plant
    water_me if RPi::GPIO.high? PIN_NUM
  end

  private

  def water_me
    @slack.chat_postMessage(
      channel: SLACK_CHANNEL,
      text: ":wave: Hey, I'm the plant on the desk.\nI really need a :shower: it's like a :desert: in here.",
      as_user: true
    )
    @logger.info 'I need watering...'
  end
end

Thirsty.run!