Let’s say you have a couple of sensors attached to an ESP8266 running MicroPython. You’d like to sample them at different frequencies (say, one every 60 seconds and one every five minutes), and you’d like to do it as efficiently as possible in terms of power consumption. What are your options?

If we don’t care about power efficiency, the simplest solution is probably a loop like this:

import machine

lastrun_1 = 0
lastrun_2 = 0

while True:
    now = time.time()

    if (lastrun_1 == 0) or (now - lastrun_1 >= 60):
        read_sensor_1()
        lastrun_1 = now
    if (lastrun_2 == 0) or (now - lastrun_2 >= 300):
        read_sensor_2()
        lastrun_2 = now

    machine.idle()

If we were only reading a single sensor (or multiple sensors at the same interval), we could drop the loop and juse use the ESP8266’s deep sleep mode (assuming we have wired things properly):

We’re all looking for ways to keep ourselves occupied these days, and for me that means leaping at the chance to turn a small problem into a slightly ridiculous electronics project. For reasons that I won’t go into here I wanted to generate an alert when a certain WiFi BSSID becomes visible. A simple solution to this problem would have been a few lines of shell script to send me an email…but this article isn’t about simple solutions!

CircuitPython is “an education friendly open source derivative of MicroPython”. MicroPython is a port of Python to microcontroller environments; it can run on boards with very few resources such as the ESP8266. I’ve recently started experimenting with CircuitPython on a Wemos D1 mini, which is a small form-factor ESP8266 board.

I had previously been using Mike Causer’s micropython-tm1637 for MicroPython to drive a 4 digit LED display. I was hoping to get the same code working under CircuitPython, but when I tried to build an image that included the tm1637 module I ran into: