11

CAN I HACK IT?

A Bluetooth RGB LED light bulb?

Can we harvest a smart bulb for parts?

hat can you get for £13? Well,

it seems quite a lot if you are

prepared to tear something

apart. This issue we take a look

at a cheap Bluetooth speaker

embedded in an RGB LED bulb.

Before we get into the teardown, a word of warning.

If you plug in this bulb before the teardown, there

is a good chance that the capacitors used in the

conversion of AC to DC power on the adapter board

will still have a charge and could give you an electric

shock. So, do not plug it in before taking them apart

unless you fully understand the appropriate ways

of working with mains electrics and high voltage

capacitors (you should still take every precaution

during the teardown). If you have never handled

components at mains power, ask someone who has

been properly trained to help you. With the warning

over, let’s take it apart...

GENERAL CONSTRUCTION

The bulb is made from strong plastic that is hard

to work with using hand tools. The LED light

diffuser is a softer plastic, but not easy to work

with. Removing the diffuser requires turning

the bulb until a click is heard. This releases

the diffuser, but you may need to use

‘spudgers’ to lever the plastic apart, as our

bulb also had a sealing layer of glue.

POWER

As this is a UK bulb, it is powered from

240 V AC mains power. This is via a step

down buck power converter board, which

converts 240 V AC to 5 V DC. So we can

desolder the board and put it safely in the

bits box for a future project. (Again, don’t

plug this into the mains before the teardown

as the capacitors will hold a charge.) We can safely

power the lights and the Bluetooth speaker using just

a 5 V 1.5 A supply. In fact if we removed the lights, we

can power just the Bluetooth audio and speaker with

400 mA, which can be easily supplied from a standard

USB port. But if we want to keep the LEDs, then we

really need to use a higher capacity power supply as

the white LED ring pulls around 900 mA of current,

red 530 mA, green 530 mA, and blue 510 mA. This is

as well as the 400 mA pulled for the Bluetooth audio.

ELECTRONICS

We are very lucky as this bulb is a goldmine for parts!

In the bulb we have an infrared-controlled RGB LED

ring, a configured Bluetooth audio device that works

A Bluetooth RGB LED

light bulb?

Can I Hack It?

W

Les Pounder

@biglesp

Les Pounder loves

taking things to

pieces and seeing

how they work. He

teaches others as part

of the Raspberry Pi

Foundation’s Picademy

event. He blogs over

at bigl.es

YOU’LL NEED

Elelight LED

E27 12 W 220 V

Music Bulb

COST

£12.99

WHERE

hsmag.cc/YqWGpt

Right

Inside this innocent

bulb there are five

components that we

can build into much

greater projects