# Set a timer - Virtual IoT Hardware and Raspberry Pi
In this part of the lesson, you will set a timer on your virtual IoT device or Raspberry Pi based off a command from the IoT Hub.
## Set a timer
The command sent from the serverless function contains the time for the timer in seconds as the payload. This time can be used to set a timer.
Timers can be set using the Python `threading.Timer` class. This class takes a delay time and a function, and after the delay time, the function is executed.
### Task - set a timer
1. Open the `smart-timer` project in VS Code, and ensure the virtual environment is loaded in the terminal if you are using a virtual IoT device.
1. Add the following import statement at the top of the file to import the threading Python library:
```python
import threading
```
1. Above the `handle_method_request` function that handles the method request, add a function to speak a response. Fow now this will just write to the console, but later in this lesson this will speak the text.
```python
def say(text):
print(text)
```
1. Below this add a function that will be called by a timer to announce that the timer is complete:
This function takes the number of minutes and seconds for the timer, and builds a sentence to say that the timer is complete. It will check the number of minutes and seconds, and only include each time unit if it has a number. For example, if the number of minutes is 0 then only seconds are included in the message. This sentence is then sent to the `say` function.
1. Below this, add the following `create_timer` function to create a timer:
This function takes the total number of seconds for the timer that will be sent in the command, and converts this to minutes and seconds. It then creates and starts a timer object using the total number of seconds, passing in the `announce_timer` function and a list containing the minutes and seconds. When the timer elapses, it will call the `announce_timer` function, and pass the contents of this list as the parameters - so the first item in the list gets passes as the `minutes` parameter, and the second item as the `seconds` parameter.
1. To the end of the `create_timer` function, add some code to build a message to be spoken to the user to announce that the timer is starting:
Again, this only includes the time unit that has a value. This sentence is then sent to the `say` function.
1. At the start of the `handle_method_request` function, add the following code to check that the `set-timer` direct method was requested:
```python
if request.name == 'set-timer':
```
1. Inside this `if` statement, extract the timer time in seconds from the payload and use this to create a timer:
```python
payload = json.loads(request.payload)
seconds = payload['seconds']
if seconds > 0:
create_timer(payload['seconds'])
```
The timer is only created if the number of seconds is greater than 0
1. Run the app, and ensure the function app is also running. Set some timers, and the output will show the timer being set, and then will show when it elapses:
