Introduction: AC Dimmer for Philips Hue

About: Hobbyist.

Philips hue is a great system to control lighting in the home. Unfortunately, it lacks two essential components that Philips does not manufacture itself: An actuator with which voltage can be switched (e.g. a smart plug) and a dimmer with which any and multiple lights can be dimmed at once. In this tutorial I will deal with a dimmer.

The goal is to control multiple standard GU10 lamps at once with only one zigbee component. I don't like the fact that with 6 lamps, which I only want to control together anyway, each one consumes 0.5 w power in standby mode.

What did I want to achieve?

  • dimming of several standard lamps simultaneously via a zigbee connection to the hue Bridge
  • low standby power consumption
  • built with original hue components, as these have a higher reliability than third party components and support more functions (power-on behavior, updates, ...)

Since I am not a native speaker, please forgive a few mistakes. If you find one, please let me know and I will correct it.

So here we go!

This tutorial was inspired by another one on this platform, especially the comments were very helpful to build it. Your can find it here:

An important note: Here you also play with high tensions. If you can't handle it, don't do it. Anything between a burned house and the end of the world can happen. All at your own risk.

Step 1: What Do You Need?

Step 2: Pair Your Bulb

Pair your hue bulb to your bridge. This should be done before tearing down the bulb into parts.

Step 3: Bulb Teardown

First the dome must be removed. This can be done either by force or with a saw. I recommend simply sawing off the dome. But be careful not to damage the protruding board.

Afterwards the silicone must be cut once around and the connectors (marked in the picture) must be desoldered. Then the LED board can be levered off with a screwdriver.

After the LED board has been removed, the main board can be pulled out upwards with a little force. The connectors at the bottom of the lamp, which connect the board to the socket, will tear off.

Step 4: Removing the Daughterboard

Next, the white daughterboard must be detached from the motherboard. The first step is to remove or at least cut the white glue, which is the glue between the two boards. Then the solder points on the backside of the motherboard have to be desoldered. Then the white daughterboard can be pulled of from the mainboard.

On the pictures you can see four important contacts. We work with GND, 5V and PWM. GND and 5V are on the back of the board shown here. The soldered line to ON/OFF is not relevant for this project (was for debugging).

In the next step you have to connect one cable each with PWM, 5V and GND. This can be especially difficult with PWM because the contact is very small. Please be careful not to solder too hot as this can damage the board and components.

Step 5: Building the Circuit

Wire the circuit as shown in the image.

Step 6: Installing the Arduino Software

  1. Download and Install the Arduino IDE

  2. Add the dimmer library to your Arduino Environment from GitHub. If you don't know, how to manually install libraries to the arduino IDE, have a look at the linkes tutorial.

  3. Install additional drivers for your china clone arduino.
    As this is quite different with each arduino clone, I can not help you with this.
    If you bought a genuine arduino, you can skip this.

  4. Download the hue.ino file from below

  5. Flash the hue.ino to your arduino nano
    If you don't know, how to open and to flash the hue.ino to your arduino nano, please have a look at the official arduino guide.


Step 7: Done!

It should be working now. Shortly after powering your Arduino via USB, the hue bulb should be shown as "reachable" in your hue app. Please keep in mind to use a dimmable LED bulb.

I'd also recommend putting the whole thing in a nice case. This will protect the boards as well as you from the high voltage. Just make sure that the dimmer doesn't overheat.

Step 8: Troubleshooting

  • dimming is not working
    • Is your Arduino blinking? Is the hue bulb shown as "reachable" in the hue app?
    • Check the software. Is it flashed correctly?
    • Check the serial monitor within the Arduino IDE. While dimming, can you see dimming values within the monitor? If not, check your wiring. Maybe the PWM from the daughterboard is not connected correctly.
  • hue bulb is "not reachable" in hue app
    • Your daughterboard is not powered correctly. Check polarity.
  • dimmend bulb flickers
    • If the bulb is only flickering within certain dimming levels, there ist help.In line 51 of the code there is a formula that calculates the dimming value. The variable sum takes a value between 500 (full power) and 9200 (1% brightness). The formula converts this value into a percentage of the dimming. My lamps, for example, only work between 1% and 90% without flickering. Therefore the formula calculates to sum = 9200 the power = 1% and to sum = 500 the power = 90%. You can adjust this formula to change the dimming behavior.
    • If the bulb is flickering within all dimming levels, your bulbs are not compatible with the dimming module. Sorry.