Alex's Corner - Week 6 - Best Practices for Deployment

[PiAir]

OK, last one for this video. You create the interrupt handler using:

def pin_handler(arg):

From this page I understand that arg contains the Pin object. So I would be able to create one handler that handles interrupts from multiple pins, correct?
On that page, also Pin.IRQ_LOW_LEVEL and Pin.IRQ_HIGH_LEVEL are mentioned. Would I be able to for example use that so set an interrupt that triggers a funciton if the temperature provided by an DHT11 gets to a low or high level?

The documentation here is a bit outdated? It states that only the Alarm class and the Pin provide the .callback() method while at least the Bluetooth class also supports it.

Sorry about all these questions after the livestream itself!

[livius]

@PiAir
this is about voltage/state indicator
IRQ_LOW_LEVEL 0
IRQ_HIGH_LEVEL 1 - 3V3
IRQ_FALLING - The falling edge of the signal
IRQ_RISING - The rising edge of the signal

[PiAir]

@livius Ok...but when would I prefer using IRQ_HIGH_LEVEL over IRQ_RISING in an interrupt? Is it just there for redundancy or are there specific use case that would make you use one or the other?

[livius]

@PiAir
You can add or between and fire in both cases :-)
e.g.

Pin.IRQ_FALLING | Pin.IRQ_RISING

are there specific use case
This depend - e.g. how fast signal raisin/falling

[tenspot]

Hi Alex,
Thank you for posting these tutorial videos, I find them very useful.
You refer to using a configuration file for wifi password, UUID etc., I would be grateful if you would outline the structure of this file as I would like to use this technique, but am unsure how to create such a file.

Regards,

Mervyn

[PiAir]

@tenspot have a look at this config.py and this file that uses it.

Basically the config.py is a .py file where you declare the variables:

GATEWAY_ID = '11aa334455bb7788'

SERVER = 'router.eu.thethings.network'
PORT = 1700

NTP = "pool.ntp.org"
NTP_PERIOD_S = 3600`

WIFI_SSID = 'my-wifi'
WIFI_PASS = 'my-wifi-password'

Then, if you want to use them in another python file, you import it using:

import config

After that you can address any variable that you have defined in that config.py file like (for example):

config.WIFI_SSID

etc

[RobTuDelft]

@tenspot It's also a convention to write the constant 'variables' in all uppercase.

[tenspot]

@PiAir Hi, Thanks for your reply, I didn't realise it was that simple! Thanks to Rob also for your comment on capitalisation of constants. Knowledge of these things all helps to improve my code readability and style.

[bucknall]

Hi @tenspot, apologies for the delay getting back to you, I have been busy with events this week! Thanks @RobTuDelft and @PiAir for answering these questions!

[tenspot]

@bucknall No problem. Thanks again for the video tutorials.

[PiAir]

@tenspot You're welcome. And if you like video tutorials, I can also recommend the ones by Tony DiCola from Adafruit. Although they are not LoPy/Pycom specific (he often uses the Adafruit boards) they are very informative. That is how I learned microPython:

https://www.youtube.com/playlist?list=PLjF7R1fz_OOXrI15wuXeESA0aA4VzcWSi

[tenspot]

@PiAir Thanks for the link, I will check it out.