Internet of Things Lighting python

In this lab, we will learn how to control the lab lighting using a computer. This should reveal some of the amazing possibilities of the IoT, as well as some of the potential for misuse if security is not handled correctly. We will learn about this while playing with a little python scripting on Windows.

Turning the lights on and off

The lab you are sitting in contains network-accessible lighting. Look directly above you and make a note of the FIXTURE NUMBER noted one your light. Note the command provided below.

import requests
url = 'http://10.50.41.230/api/override'
fixtureNo = FIXTURENUMBER
json = {"target": "fixture","num": fixtureNo,"intensity": 255,"red": 255,"green": 0,"blue": 0,"temperature": 255,"fade": 1.0,"path": "Default"}
requests.put(url=url,  data=json)
print("Check your LED!")

Copy the lines above into notepad++, and then change the FIXTURENUMBER to the light found on your computer overhead. save the file to your desktop named IOT-LED.py

How do you think you could switch the light off? Play with the parameters and ask for help if you need some guidance.

Some Basic Python Programming

The internet of things is all about communicating with other devices and services, this section will continue with python requests and work with response data.

import requests
url = 'http://api.openweathermap.org/data/2.5/weather?q={city name}&appid={API key}'
response = requests.get(url=url)
print(response)

Save the file as hello.py

open command prompt

cd Desktop
python hello.py

Press Ctrl+C to stop the program when you have seen enough hello worlds.

Tasks

• Can you modify the program to print ten Hello worlds?
• Can you modify the program to see if you can turn the light on and off every second?
• After you have done this, can you modify the program to change the colour every second?

Measuring the CPU temperature

We would like the operation of the fan to turn on to cool the CPU on your mini computer. The following command will show you the current temperature of your CPU

cat /sys/class/thermal/thermal_zone2/temp

Write down the CPU temperature at idle time.

Read the following code and see if you can work out what is going on. Open a new file, paste the code below and save it as temperature_visualisation.sh

#!/bin/bash

temp=$(cat /sys/class/thermal/thermal_zone2/temp)
echo $temp

Tasks

• Use your knowledge of looping from the previous section to continually check and print the temperature for 2 minutes.
• See if you can integrate the line below to print a more meaningful temperature:

n=1000
temp=$((temp/n))

Generating CPU load

Open a second terminal window, while your previous code is running and paste in the following command to generate some load on your CPU

stress --cpu 8

How hot does your CPU get? Hit ctrl+c to close this window.

If statements

Computer programs can take different actions/paths based on circumstances. Run the following code:

#!/bin/bash

temp=$(cat /sys/class/thermal/thermal_zone2/temp)
n=1000
temp=$((temp/n))
echo $temp

if [ $temp -gt 60 ]
then
 echo "Its really hot"
elif [ $temp -gt 50 ]
then
 echo "Its sorta hot"
elif [ $temp -gt 40 ]
then
 echo "Its coolish "
elif [ $temp -gt 30 ]
then
 echo "Its cool"
else
 echo "Dunno"
fi

You can change/test the temperature of the CPU using the load command used earlier.

Challenging Tasks

• Can you modify the code to change to a different colour based on the temperature, you can also play with the fade?
• Can you then loop over this code block for 10 minutes or 600 seconds, it may be helpful to use the sleep command again and retest the temperature every second?