نشاط

# منبه الباب اللاسلكي

مُتقدم | MakeCode, Python | البوصلة, الراديو, شاشة LED | أجهزة الاستشعار, الاتصال, التحديد, المغناطيسية, منفذ العلاقات, موجات الراديو

## الخطوة 1: اصنعها

### ماذا يعني؟

إنذار لاسلكي لتحذيرك عندما يفتح شخص ما الباب - أو يتركه مفتوحًا.

### 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.

### كيف يعمل ؟

• 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.

### ما تحتاجه

• two micro:bits and at least one battery pack
• مغناطيس
• 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

## الخطوة 2: برمجها

### مستشعر / ناقل:

``````1from microbit import *
5
6while True:
7    if button_a.was_pressed():
8        display.scroll(compass.get_field_strength())
9    if compass.get_field_strength() < 100000:
10        display.show(Image.DIAMOND_SMALL)
12    else:
13        display.clear()
15    sleep(2000)
16``````

### منبه / مستلم:

``````1from microbit import *
2import music
6
7while True: