Choosing LED diode for BBMagic MOTION


BBMagic MOTION has red LED diode onboard. You can connect pin 2 of the module to ground (pin 1) to turn on motion detection LED indication.

BBMagic MOTION pinout
But we have another possibility too. We can:

  • choose our own LED diode
  • solder it with series resistor to pins 5 (LED cathode) and 6 (LED anode with resistor) of the module
  • leave pin 2 unconnected

Then the onboard red LED is switched off and the new one will blink when motion detection occures. How to choose optimal components?
Lets do it now !!

We will need:

1. BBMagic MOTION sensor module

BBMagic MOTION
2. CR2032 battery with holder

CR2032 i holder
You can choose another power source with voltage between 2,7-3,3V. For example 2xAA or 2xAAA batteries.

3. LED current limit resistor
In this particular case there is a trade off between LED power consumption and total amount of light emitting. Resistor in range 3,3k to 4,7k seems to be optimal.

4. LED diode
This choice is critical for final effect. There are few aspects:

  • LED should have high brightness to current ratio
  • LED shouldn’t scatter the light
  • LED shouldn’t be in any kind of SMD package
  • LED should work in voltage range 2,7V-3,3V (BBMagic MOTION power supply voltage)

Ordinary LED (diffuse LED) is not good for our purposes. It draws too much current and even doesn’t light with voltage around 3V.
LED matowe
Our choice is super bright waterclear LED with narrow viewing angle. Everybody has own favourite color but we suggest using green or blue. Here are some LED tests:
Super bright waterclear green LED (525nm) – diameter: 5mm – brightness: 10000 mcd ; viewing angle: 30°

LED dla BBMagic MOTION

Supply voltage series resistor LED current
2,7V 4,7k 33uA
3,3V 4,7k 138uA
Super bright waterclear blue LED – diameter: 4,8mm – brightness: 330-750 mcd ; viewing angle: 100°

LED dla BBMagic MOTION
Supply voltage series resistor LED current
2,7V 4,7k 64uA
3,3V 4,7k 177uA
Super bright waterclear red LED – diameter: 5mm – brightness: 3000-4200 mcd ; viewing angle: 60°

LED dla BBMagic MOTION
Supply voltage series resistor LED current
2,7V 4,7k 221uA
3,3V 4,7k 340uA
After choosing right LED and resistor solder it to pins 5 and 6 of the BBMagic MOTION. Dont forget to leave pin 2 unconnected.

BBMagic MOTION na ścianie

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