It’s a question that keeps coming back to me in various ways. It’s about ceiling lighting that still has a dimmer on the switch. What is a great thing for classic halogen or LED lamps and increases convenience is absolute poison for Philips Hue. One of the letters comes from Hueblog reader Frank. He writes:
Now I have a question. I bought a Hue Ensis lamp and would like to install it above my dining table. There is currently another lamp connected to an electronic switch/dimmer (from Busch-Jäger). Is it generally the case that Hue lamps cannot be connected to such switches/dimmers?
Unfortunately, I can’t explain exactly what happens electrically with my half-knowledge. But even if a dimmer is fully turned up, it will almost certainly cause the connected Philips Hue lamps to start flickering and can no longer be controlled properly. So there is only one solution: the dimmer has to go!
Replacement with the Philips Hue wall switch module
If you have to replace the dimmer with a classic switch or push-button anyway, then I recommend installing the Philips Hue wall switch module straight away. While the ceiling lamp is set to continuous current, the small Philips Hue module is connected directly to the switch or push-button that is disconnected from the circuit. This can then be configured smartly in the Hue app. Another advantage: everything looks the same as before and nobody has any problems with operation.
And if you decide to use a push-button, you can even use the wall switch module to easily create a dimming function – just as you did before with classic ceiling lighting and the hardware dimmer. You can also use the smart switch to easily switch between different scenes from the Hue app.
Philips Hue sells the wall switch module, which is powered by a button cell and to which two adjacent switches or buttons can be connected, individually for 44.99 euros or in a twin pack for 79.99 euros.
Philips Hue wall switch module
$44.99 / £39.99 / €44,99
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For those who want to know what’s going on with an electrical dimmer, here is a simplified explanation:
Mains electricity is alternating current, 120V at 60Hz in north America, and 230V at 50Hz in Europe. I’ll explain for Europe, but it’s the same with different values.
The voltage from the mains is a sine wave ∿, going from 0V to +312V, then back to 0V, then to -312V, then back to 0V again, before repeating the cycle again, 50 times a second. The average (equivalent direct current power, see RMS of a sine wave) is 230V.
Electronic circuits, and that includes LEDs, usually require a direct current at a lower voltage, which means every single electronic device includes a power supply circuit that converts that alternating current ⏦ into direct current ⎓, typically by rectifying it to + only, and smoothing it by storing extra power during peaks, and releasing that power when the sine wave goes around 0V.
The power supply is designed to provide a (almost) perfectly stable fixed voltage, its components being picked according to the expected input alternating current, and power needed by the electronics.
If you want to dive deeper into this, look at half and full bridge rectifiers, and capacitors. But basically it takes either only the + part of the sine wave and loses the – part, or reverses the – part as well to get both as +, reducing the time without power, then a capacitor acts as a small rechargeable battery that stores some power during peaks, enough to provide the power required by the electronics during the whole duration of the thoughs (valleys).
If the throughs are wider, or if the electronics require more power, the capacitor must be larger to store more power during peaks so it doesn’t run out of power during throughs.
Incandescent and halogen lights were not electronic devices. They simply use a wire which the alternating current goes through, heating it so much it glows. It was flickering at 100Hz because the alternating current source follows a sine wave, but it wasn’t noticeable.
Electrical dimmers use a technique called phase-cut dimming. It can be leading-edge dimming or trailing-edge dimming, but the idea is always that it cuts the power for a certain percentage of each phase, either at the beginning or at the end of a cycle. The light bulb would still flicker at the same frequency, but current would flow through it for a shorter time of the cycle, making it heat up less, emitting less light. This worked well for old bulbs.
A dimmer usually never let the whole 100% go through, so once you have a dimmer on an electrical circuit, you’re chopping part of the sine wave.
Now imagine that being used with an electronic device and its power supply, you’re forcing the provided power to stay at 0V for a longer period of time each cycle.
This means the capacitor does not get enough power to recharge, and get empty before the next peaks arrives, and it cannot sustain the stable fixed-voltage it’s supposed to provide to electronic components.
The voltage will drop, and could even turn off completely, 50 times a second.
Many electronic components can get damaged by too regular on/off cycles, and you’re providing it with a simulation of toggling their power switch 180000 times per hour. For devices that contain a CPU, or a microcontroller, RAM memory cells can have their stored values get corrupted if they cannot refresh on time (DRAM) or don’t get a constant power supply (SRAM), so you’ll be making anything software-controlled pretty much random.
Things like a computer, or the zigbee controller in a Hue bulb, will do random things or crash. And you’re reducing the life expectancy of every chip and component with the pulsed power abuse.
So even if it seems to work, and you’re lucky you don’t get reliability issues with your LEDs, you’re shortening their lifespan. You should always remove any legacy dimmer when installing LEDs.
And this is also the reason I’m against “dimmer-compatible” LEDs. They can adjust the capacitor and circuit to support it, but the pulsed power source will still make them shorter-lived than digitally-dimmed LEDs.
I’ve been driving myself nuts for months trying to find a Zigbee rotary controller that I could use to control my Hue lights (single press to toggle on/off; double press to cycle through scenes; rotate to dim; press and rotate to tune whiteness).
I’ve managed to do this (mostly) with the Lutron Aurora and successfully by integrating Hue with the Aqara Home app through Matter and using the Aqara wireless Dimmer Knob H1 (you don’t need your Aqara hub to be set to China). The problem with both of these controllers is that they’re not so aesthetically pleasing. I would much prefer to have a wireless in-wall module that could work with whatever faceplate and knob I desire (much in the same way the Hue In-Wall Module works).
If anyone knows of any product that will do this – or wants to bring one to market – please let me know!
What about these:
I’m don’t know if these work with hue but a quick search found these:
https://www.currys.co.uk/products/wiz-smart-dial-switch-white-10267170.html
https://www.tp-link.com/uk/home-networking/smart-switch/tapo-s200d/
https://flic.io/twist
@GabboCH
WiZ uses Wi-Fi, it would require an app running on some device (PC, controller,…) to receive commands from the dial switch and trigger commands through the Hue bridge (Zigbee), and that’s if their protocol is available to 3rd parties.
TP-Link Tapo is also Wi-Fi, but last time I checked was even worse because they kept their protocol proprietary, and required an active subscription to use their devices… I’d avoid at all cost.
Flic seems like a nice product, apparently, they use Bluetooth LE, and require their own bridge, but at least it is compatible with Matter, so it might be possible to create rules that trigger actions on the Hue bridge through Matter.
I appreciate your suggestions, but they don’t really address my question. I’ve already managed to achieve my goal with large, external knobs (Lutron Aurora and Aqara H1), but I’m looking for a module that can sit behind a faceplate (similar to the Candeo and Samotech modules, but those are end devices not controllers).
I ran Hue in a bunch of GU10 sockets in a flat that we rented, they had dimmers so we left them turned to maximum and they seemed to work okay.
Since moving to our own house (no dimmers) I’ve found the oldest bulbs from the old flat have gradually been dying out around 5 years after I got them.
I’m pretty sure they’re all damaged by the dimmers. So even if it seems fine, there’s a good chance they’ll die early, but maybe not super early. For me it was worth it to have Hue in the flat for the years we were there.