BitheadsDev/Microbit-Thermostat-Controlled-Fan

If Microbit reaches a certain temperature a fan will be switched on

Microbit Thermostat Controlled Fan

Aims of the app

To control a fan once the Micro:bit temperature sensor is above a user selected temperature

View Videos

• Part one – showing the fan in action: https://www.youtube.com/watch?v=0b-i0Yfr5sA
• Part two – showing how to construct the circuit: https://www.youtube.com/watch?v=7HUZakzsjN4

View the circuit

There is a png and a Fritz file included in this repo that illutrates how the circuit was put together.

Details and controls

• The user can select the temperature that the fan will be active above by using the Micro:bit buttons
• The user will be able to control the fan speed by tilting the device

Things you need

• A Micro:bit
• A USB lead
• A computer to copy and write the code
• Kittronik Inventor's Kit for BBC Microbit, specifically:
  • 1 x breakboard
  • 1 x breakout board
  • 1 x transistor
  • 1 x 2.2Ω resistor
  • 1 x Terminal connector
  • 1 x motor
  • 3 x male to female jumper wire
  • 1 x fan blade

Things you should learn

• How to create a multi-stage application that passes data from one stage to another
• Using buttons and gestures to control an external device
• How to use the output pins to power an external device
• Creating a circuit that uses a transitor to amplify current
• Build understanding of pulse width modulation

Initial pseudocode runthrough

setTemp:
    if B was pressed:
        increment (+=1) fanOnTemp by 1
    else if A was pressed:
        decrement (-=1) fanOnTemp by 1

    if no buttons have been pressed for 2000 seconds:
        Call: fan

fan:
    if temperature >= fanOnTemp:
        if temperature >= fanOnTemp:
            Supply on signal to pin0 x/5 max value amount of times (this is pulse width modulation as the pin is either on or off)
            Light up the LEDs 3 rows from the bottom to represent x/5 power
    if B was pressed:
        increment (+=1) fanOnTemp by 1
    else if A was pressed:
        decrement (-=1) fanOnTemp by 1
    else:
        while pin2 is touched:
            Increment FanSpeed up to 5 and then cycle to 1
            Show x/5 rows of LEDs lit up from the bottom

Possible extensions

• Hooking up an external thermostat to get a more accurate temperature reading.
• Alternatively, use two or more Microbits to communicate through the radio function their temperatures and get an average temperature over an area.