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Alarma de puerta inalámbrica

Avanzado | MakeCode, Python | Brújula, Pantalla LED, Radio | Comunicación, Magnetismo, Ondas de radio, Operadores relacionales, Selección, Sensores

Paso 1: Hazlo

¿Qué es?

Una alarma inalámbrica que te advierte cuando alguien abre una puerta, o la deja abierta.

How to make it

  • You will need two micro:bits with different code on each. One micro:bit acts as a radio transmitter and the other as a radio receiver.
  • Attach the transmitter micro:bit and battery pack to the corner of a door frame and attach a magnet close to it on the corner of a door.
  • Place the receiver micro:bit anywhere nearby.
  • If the alarm doesn’t work as you expected, you may need to change the magnetic force strength number in the transmitter code. Pressing button A shows the current magnetic force reading. Use this to decide on the threshold number, taking readings with the door open and closed.

Cómo funciona

  • The transmitter program uses the micro:bit’s compass (magnetometer) input sensor and a loop to measure the strength of the magnetic field every two seconds.
  • It uses selection so when the magnetic field strength falls below a certain level (the threshold), it sends a radio signal ‘open’. If the magnetism reading goes above the threshold, it sends the signal ‘closed'.
  • When the receiver micro:bit receives the signal ‘open’, a cross appears on its LED display and an audible alarm sounds. When it receives the signal ‘closed’, a tick appears on its LED display and no sound plays.

Qué necesitas

  • two micro:bits and at least one battery pack
  • un imán
  • some adhesive putty to fix a magnet to a door and a micro:bit to a door frame
  • if you have a V1 micro:bit and want to hear an audible alarm, optional headphones, buzzer or speaker and crocodile clip leads to attach them

Paso 2: Prográmalo

Sensor / transmisor:

1from microbit import *
2import radio
6while True:
7    if button_a.was_pressed():
8        display.scroll(compass.get_field_strength())
9    if compass.get_field_strength() < 100000:
11        radio.send('open')
12    else:
13        display.clear()
14        radio.send('closed')
15    sleep(2000)

Alarma / receptor:

1from microbit import *
2import music
3import radio
7while True:
8    message = radio.receive()
9    if message:
10        if message == 'open':
12  ["C4:4"])
13        if message == 'closed':

Paso 3: Mejóralo

  • Usa múltiples micro:bits para controlar el estado de diferentes puertas enviando diferentes mensajes de radio, como "puerta trasera abierta".
  • Utiliza una variable para medir cuánto tiempo se queda cada puerta abierta – ¿podría ayudar a ahorrar en calefacción?