SolutionsToTheExerciseOnSwitches < IoT_Course

---+ Solutions to the Exercise 3: Switches
---++ Exercise 1:

This is very similar to switching a LED on or off. Again a single GPIO line is used. This time however the pin in programmed as input and we can add a pullup or pulldown resistor:

<literal>_PB_PIN = 22<br />pushButton = Pin(_PB_PIN,Pin.IN,Pin.PULL_UP) &nbsp;</literal>

Once the pushButton pin is defined we can get its current state with:

<literal>state = pushButton.value()</literal>

%ATTACHURL%/pbPoll.py.txt
---++ Exercise 2:

The !MicroPython documentation includes a chapter on writing interrupt service routines

http://docs.micropython.org/en/latest/reference/isr_rules.html

How to do this with GPIO lines is described in

http://docs.micropython.org/en/latest/esp8266/tutorial/pins.html

When using interrupts you may run into problems with bouncing of mechanical switches. The transition is not a single clear cut step function but may flip back and forth. Have a look at [[http://docs.micropython.org/en/latest/pyboard/tutorial/debounce.html][http://docs.micropython.org/en/latest/pyboard/tutorial/debounce.html ]]for an explanation on how to eliminate this problem (software debounce algorithm).

%ATTACHURL%/pbInterrupt.py.txt
---++ Exercise 3:

Nothing much to be said here. Have a look at the solution:

%ATTACHURL%/pbIntLED.py.txt
---++ Exercise 4:

There is no difference in programming between a mechanical and a PIR switch. Just the GPIO line on which the switch is connected must be adapted.

%ATTACHURL%/pirPoll.py.txt

-- %USERSIG{UliRaich - 2020-05-06}%

---++ Comments

%COMMENT%

Attachments

Topic attachments
I	Attachment	History	Action	Size	Date	Who
png	builtinLED.png	r1	manage	17.8 K	2020-05-06 - 09:32	UliRaich
txt	pbIntLED.py.txt	r1	manage	0.9 K	2020-06-15 - 09:39	UliRaich
txt	pbInterrupt.py.txt	r1	manage	0.8 K	2020-06-15 - 09:39	UliRaich
txt	pbPoll.py.txt	r1	manage	1.0 K	2020-06-15 - 09:39	UliRaich
txt	pirPoll.py.txt	r2 r1	manage	1.0 K	2021-11-26 - 21:13	UliRaich

This topic: IoT_Course_English > WebHome > Solutions > SolutionsToTheExerciseOnSwitches
Topic revision: r4 - 2021-11-26 - UliRaich