Smart Fan Control System with micro:bit

DFRobot Mar 26 2018 2146

from microbit import *
mode = [700, 900, 1023]
while True:
   for speed in mode:
      print(speed)
      pin8.write_analog(speed)
      sleep(1000)

from microbit import *
fan_switch = False
while True:
   if pin12.read_digital():
      fan_switch = not fan_switch
      print('ON' if fan_switch else 'OFF')
      pin8.write_digital(int(fan_switch))
      while pin12.read_digital():
         sleep(100)

from microbit import *
fan_switch = False
fan_mode = ["slow", "medium","fast"]
fan_power = [700, 900, 1023]
def fan_mode_switch(value):
   interval = int(1023/3)
   for i in range(3):
      if value >= i * interval and value < (i+1)*interval:
         break
   return fan_mode[i], fan_power[i]

previous_mode, power = fan_mode_switch(pin0.read_analog())

while True:
   if pin12.read_digital():
      fan_switch = not fan_switch
      print('Fan status: ' + ('ON' if fan_switch else 'OFF'))
      while pin12.read_digital():
         sleep(100)
   if fan_switch:
       mode, power = fan_mode_switch(pin0.read_analog())
       if mode is not previous_mode:
          previous_mode = mode
          print("Fan mode: ", mode)
          pin8.write_analog(power)
       else:
          previous_mode = 'OFF'
          pin8.write_analog(0)
       sleep(300)

from microbit import *
fan_switch = False
fan_mode = ["slow", "medium","fast"]
fan_power = [700, 900, 1023]
def fan_mode_switch(value):
   interval = int(1023/3)
   for i in range(3):
      if value >= i * interval and value < (i+1)*interval:
         break
   return fan_mode[i], fan_power[i]

previous_mode, power = fan_mode_switch(pin0.read_analog())

while True:
   if pin12.read_digital():
      fan_switch = not fan_switch
      print('Fan status: ' + ('ON' if fan_switch else 'OFF'))
      while pin12.read_digital():
         sleep(100)
   if fan_switch:
      mode, power = fan_mode_switch(pin0.read_analog())
      if mode is not previous_mode:
         previous_mode = mode
         print("Fan mode: ", mode)
         pin8.write_analog(power)
   elif pin1.read_digital():
      fan_switch = True
      print('Fan status: ' + 'ON')
   else:
      previous_mode = 'OFF'
      pin8.write_analog(0)
   sleep(300)

Smart Fan Control System with micro:bit

In this article, we will show you how to create a smart fan control system with BBC micro:bit.

Hardware components:DFRobot BOSON starter kit for micro:bitBBC micro:bit board

Introduction

Micro:bit is a small computer designed by BBC, one interested in it may refer to its official website for more information, there are rich interesting projects suitable for beginners.

Preparation

Building the fanThe main hardware in this article consists of LEGO bricks, please refer the following picture. You can design your own fan, but please make sure there are enough room to put on four BOSON components, including sensors and motors.

Software InstallationMicro:bit officially recommends two programming environments: one is graphical JavaScript blocks editor, and the other is the MicroPython which would be used in this project.Microbit JavaScript Blocks Editor

MicroPython Online Editor

In addition to using the online version seen on the micro:bit website, we can also download the Mu Editor (https://codewith.mu/#download) which is highly recommended by MicroPython. This editor is simple and specially designed for beginners.

Python is a cross-platform language. It can run directly on Windows, Mac OSX and every Linux distributions. Please download the proper installation file according to your operating system.

After the installation is finished, you can open the Mu editor as the picture below. Click the flash button to upload program to micro:bit through USB cable.

Implementation

Demo 1: Control the MotorFirst add the motor component in the BOSON kit onto the middle base. For the base, please feel free to design or modify, yours doesn’t have to be exactly the same with ours.

Connect a BOSON DCmotor component to micro:bit extension board’s P8 port with a Boson cable.

Python Code of Demo 1

The use of the function write_analog in the code is to continuously change the power, if we use write_digital, then we can control the fan on and off.

Python Code of Demo 2

Code Explanation of Demo2

In this example, we focus on whether the switch is toggled. So we use write_digital function this time instead of analog_write in previous example.

We declare a variable fan_switch to store the status of the fan(connect to P12). Everytime the user pressed the button, the fan will turn on and vice versa. Apply the fan status on the motor would achieve the function switching fan! The while loop will repeat every 100ms (sleep(100) ).

This video demos how to switch the fan by the button.

Demo 3: Adjust motor power

Now we are going to combine the above two examples and add a knob to adjust the motor power.

Please follow the picture below to add a Boson knob sensor on the base, and connect it extension board’s P0 with a Boson signal wire.

Python Code of Demo 3

Code Explanation of Demo 3

This program seems a bit more complicated than above ones. Let's see detail in this program!

First, we defined two variables fan_power and fan_mode more precisely than the previous code, and we also defined a function named fan_mode_switch to handle the fan mode and power according to the input value.

Demo 4: Smart Fan

To make the fan smarter and more user friendly, we want to add some function which common fan does not have. So we add a Boson motion sensor on micro:bit, please connect it to extension board’s P1, as the picture below.

What is motion sensor? In fact, its formal name is PIR (Passive Infrared Sensor). We use it to detect whether there is something nearby. A common application is to turn on a stair light automatically when people walking through.

Note: PIR motion sensor is a digital sensor to tell there IS or IS NOT something in its range, you should use ultrasonic sensor or laser range finder to measure the distance by centimeter or inch.

Now we hope that this smart fan would turn on by itself when detecting a human hand waving without physically touching the switch.

Python Code of Demo 4

Exercise

In addition to the above functions, how can we add more features on our smart fan? For example, switch to the natural wind mode if the button is pressed for a while, or use the knob to set the time to auto sleep (Hint, use Python’s time library). Try and have fun!

Hardware components:
DFRobot BOSON starter kit for micro:bit
BBC micro:bit board

Building the fan
The main hardware in this article consists of LEGO bricks, please refer the following picture. You can design your own fan, but please make sure there are enough room to put on four BOSON components, including sensors and motors.

Software Installation
Micro:bit officially recommends two programming environments: one is graphical JavaScript blocks editor, and the other is the MicroPython which would be used in this project.
Microbit JavaScript Blocks Editor

Demo 1: Control the Motor
First add the motor component in the BOSON kit onto the middle base. For the base, please feel free to design or modify, yours doesn’t have to be exactly the same with ours.