Hue Gentle Hack

2023-05-04 08:00:28

I’ve bought a bunch of Philip’s Hue Colour gentle bulbs, so I believed it is perhaps enjoyable to take one aside and do a little bit of hacking.

In case you’re right here from Hacker Information – watch the video – it’s really good! (Even when I do say so myself)

Disassembling the Hue Gentle Bulb

First, we have to open up the sunshine bulb. Utilizing a spudger, rigorously pry the plastic diffuser away from the bottom, working across the cussed silicon sealant. I bought barely bored and as soon as I’d made a niche shoved a screwdriver in there to pry it off.

Subsequent, take away the internal diffuser and the aluminum PCB with the LEDs on it. You would possibly must take away some surrounding plastic and steel for this.

To pop off the bottom of the sunshine bulb I squashed it in a vice till the plastic cracked – chances are you’ll need to discover a much less damaging methodology.

Contained in the Hue Gentle Bulb

The ability board and the logic board are separate elements, they seperate fairly simply even when lined within the potting compound. As soon as they’re separate you may assault every on in flip. Eradicating the potting compound from the ability board is fairly simple. For the logic board there’s a plastic encompass and potting compound will be fairly troublesome to get off – it’s simple to lose or harm a number of the small ICs.

However after a bit of labor you’ll find yourself with these three PCBS:

The Energy Board

There’s nothing too thrilling about this – it takes within the mains voltage, runs it by means of a bridge rectifier after which there’s a swap mode energy provide producing 5V together with a hight voltage (in all probability round 24V) for driving the LEDs.

LED PCB

The LED PCB has an 8-pin socket labeled A to H. B and C had been fairly simple – they simply connect with the thermistor. The opposite pins had been barely complicated, however by connecting the ability provide by means of a resistor and making an attempt completely different combos, we are able to decide which pins that management the assorted LED colours.

This provides us the marginally complicated schematic beneath – however don’t fear all will turn out to be clear:

The Logic Board

The logic board has 5 P-Channel MOSFETs, buzzing out the supply and drain of those we find yourself with this far more wise schematic.

Every set of LEDs will be bypassed by turning on the MOSFETs – it’s fairly intelligent.

The board makes use of an AP8802 step-down fixed present LED driver, able to supplying as much as 1A. It’s configured to provide round 0.5A to the LEDs. What’s very intelligent with the best way the LEDs and MOSFETs are laid out is that we solely want one LED driver chip for all of the LEDs – it is a comparatively costly element in comparison with the jelly bean MOSFETs, transistors and different elements.

The MCU on the logic board is an Atmel SAM R21, a 32-bit ARM Cortex M0+ processor with a 2.4GHz ISM band transceiver for Zigbee communication. It has 256KB of Flash and 32KB of SRAM and runs at 48MHz.

The transmitter on this makes use of a PCB antenna with a bunch of capacitors and inductors to tune it to the suitable frequency.

Does it nonetheless work? And a few extra reverse engineering

It does! If we solder some energy cables on and supply it with 5V the sunshine bulb reveals up within the Hue app on my cellphone. It we join 24V to the LED provide then they gentle up. We will management the colours from the Hue app – although since I misplaced one of many ICs we don’t get good colours.

With the board we are able to work out what alerts are coming from the MCU. These resistors listed below are related on to the MCU and undergo this set of ICs to drive the PMOS FETs. The schematic is one thing like this – we now have a stage shifter adopted by a push-pull driver related to the gate of the MOSFET.

Probing the resistors whereas altering the colour within the Hue app we work out the alerts for every of the colours and for the white LEDs.

The very last thing I checked was the management enter of the AP8802 – I wasn’t positive if this was getting used to manage the general brightnesss, however it seems that that is simply left floating and is barely pulled low when the sunshine is absolutely turned off.

With the R,G,B and white alerts labored out we are able to now solder some wires to the MCU aspect of the resistors and join them to a breadboard. By driving LEDs at low energy instantly from the MCU we are able to create varied colours and management the brightness.

That works fairly properly, we are able to management the LEDs with none issues. All three colours work and the 2 whites additionally work – although I’m suspicious that the “heat white” LEDs could also be used for yellow.