Wesley's Tool-Box

Selecting HomeKit devices that control the power, whether they be power plugs/outlets or light switches, is a bit tricky when you're living in a country with 220V mains power. This is because much of them are made to serve the U.S. market, which uses 120V. If they are designed for dual voltage it wouldn't be a big issue, but some devices don't list this capability. A Philips Hue light bulb has 110-130V printed on the U.S. version and 220-240V on the Korean version, but they all support 110 to 240V.

The list of devices that are specifically tailored towards the 220V market is growing, but still sparse. Thus, I sought and picked out the ones that were definitely 220V compatible. In the case of power plugs, products from Elgato, Koogeek, and Incipio fit the bill. Power plug solutions from iDevices are listed and confirmed as 120V only.

Despite the shapes, the smart power plugs shown above all have dual voltage support. Interestingly, the EU version of the Elgato Eve Energy is the smallest and won't block an adjacent outlet, while the US version of the device and the Koogeek P1 are larger and may block an outlet below or above. Incipio's CommandKit Wireless Smart Outlet with Metering is much larger and and longer than the competition, just like its full name. I should also note that only the Incipio devices had a problem with HomeKit pairing, where the process would succeed only on the second try, and leave a phantom entry in the device search screen that won't go away until the iPhone reboots.


Elgato's Eve Energy smart power plugs have the most regionally varied line-up, with US, EU, UK, and AU versions, all having 100-240V, 50/60Hz support. The energy monitoring function in the app is also one of the the most sophisticated in the market. So I went primarily with these plugs in my house. I bought the EU version from Germany, but since I order a lot of things from the U.S., there are some US version plugs in the house as well.

Lighting is one of the first things to be considered for being controlled in a smart home because it's an essential part of a house, and the light bulbs can be replaced relatively easily. Therefore the solutions are abundant, and even in Korea where HomeKit-compatible devices are practically non-existent in the market, Philips Hue series of smart lighting stand out as the rare exception. Only a subset are officially imported, but the available ones are priced lower than the overseas market, so I was quite happy to buy them locally. To start things off, I bought a Philips Hue White and Color Ambiance Starter Kit and a Dimmer Switch four months ago.


The kit contained three 2nd generation Hue White and Color Ambiance light bulbs and a HomeKit-compatible Hue Bridge. Buying them individually would be noticeably more expensive, so it's indeed a good value. I should note that 3rd generation bulbs with richer colours in the green spectrum were already available in overseas markets, but they have yet to be officially available in Korea even at the time of this writing. In my experience, it's not a critical difference and the 2nd generation ones hold up just fine.

Months into using the SKT Smart Home as the home IoT system, several shortfalls such as the lack of interaction beyond the main app and no actual user-side ownership of data left me feeling unfulfilled. Meanwhile, Apple's own home IoT efforts, HomeKit, had been maturing and being quite an Apple enthusiast, I thought this may be a good time to give it a try.

First appeared on iOS 8 in 2014, HomeKit finally got its own system app "Home" and a place in the Control Center with iOS 10, along with notification from accessories (iOS 10.2) and geofencing support. With the upcoming iOS 11, it's set to become even more powerful, supporting more accessory types, per-user geofencing, better timing options (offsets and delays), shorter Bluetooth LE latency, and hobbyist development of accessories.


For my first HomeKit accessories, I picked up several types of Elgato Eve sensors during my Fukuoka visits in April. Eve Weather tracks the outside temperature, humidity, and air pressure. Eve Motion senses human movement up to 9 meters in the 120 degrees' field of view. Eve Door & Window detects the opening and closing of openable items. They seemed to be good starting points for future expansion because they provide sensor data that can trigger actions.

Now, the reason why I bought them in Japan is because most of the HomeKit-enabled accessories are not sold in Korea at the moment. They are most prominently available in the U.S., but this means that anything that runs off AC power like power plugs and light switches are often 120V-only, incompatible with the 220V outlets. Battery-powered ones can be found with relative ease in many Eurasian countries. For now, I'm sourcing various accessories from the U.S., Germany, and Japan.

FYI, the sensor series for Elgato Eve are most widely available around the world and you should compare the prices when buying them from overseas. Price in Japan isn't particularly favourable, so you should pick them up from physical stores only if you're already visiting the country for other reasons.


Eve sensors are battery operated, so they can be installed freely around the house. What's more, batteries in these sensors last at least a year according to Elgato, so they need little maintenance. More than two months into their use, battery indicators have barely budged. Should the batteries eventually run out, Eve Weather and Eve Motion use standard AA batteries, so they are cheap and easy to replace.

SK Telecom's Smart Home device line-up was conspicuously missing a motion sensor. It would have nicely complemented the Jikimi home security devices. Considering that the PIR (passive infrared) sensor itself doesn't cost all that much (some as low as US$2) or complicated to work with, it wouldn't have been so hard to create a product out of it.

It turned out that SKT wanted that as a part of a much more beefed up home security solution called "T View Sense" that came out last month. It's a cloud-connected IP camera with the optional sensor package (motion, door, temperature/humidity, smoke, and carbon monoxide). The sensors requires the IP camera to function because they communicate to the server via the camera's integrated gateway. I appreciate the effort SKT is finally making to counter the IP camera efforts from the other mobile carriers (LGU+ had theirs since 2013), but the pricy nature of the camera (official price of KRW159,000 or about US$140) is off-putting to someone who's just interested the sensor alone.

So I decided to be a bit creative and repurpose one of the existing Jikimi devices into a motion sensor instead. Initially, I wanted to modify the SOS button because it was cheaper. But the fact that the alarm it makes doesn't get differentiated between the buttons made it a deal-breaker. With the door sensor, I needed to simulate the door closing/opening with a magnet, meaning that I could either attach the included magnet to a motor or use an electromagnet to fake such action.


Obviously, I chose the electromagnet because it would be far more simpler if it worked. If it generated enough magnetic field, it would act like the original magnet and cause the sensor to send a "door closed" signal. The problem was that I wasn't sure what kind or how big of an electromagnet would be necessary. After looking at various offerings on the internet, I decided to take a stab in the dark and buy a small "lifting electromagnet" used in machines for picking up metallic items. The particular model I bought for about US$5 was rated for 2.5kg at 12V DC, consuming 3W. The model number KK-P20/15 apparently indicates a 20mm outer diameter and 15mm thickness.

12V was tad higher than what I wanted, but the electromagnet works at a lower voltage with reduced pulling power. All I needed to know was whether that pull is just enough to trick the sensor, so I created a quick testing platform with my kids' electric circuit kit. As you can see here, 3V was just barely good enough for the sensor to activate. At 6V, it worked more reliably. This confirmed two things - the electromagnet I had was fit for the job and that I could make it work with a battery pack, e.g. single-cell Li-Ion battery (3.7V nominal).