The Achilles Heel of the Mikroelektronika Hexiwear is its charging: the charging and USB connector are only designed for a limited number of plug-unplug cycles, and it does not have a wireless charging capability like the Apple iWatch. Until now! I have built a DIY wireless charging system for the Hexiwear 🙂 :
Wireless Qi Charging? IKEA!!!!
I have been experimenting with wireless charing for a few weeks, including building a Qi charging station using a kit from Adafruit (see “Qi Wireless Charging Transmitter with 3D Printed Enclosure“). The problem is that getting Qi charging receivers seems not to be that simple. With my research I have found that the Apple iWatch is using Qi technology, but they tweaked it in a way that it only works with the Apple chargers/receivers (see “Apple tweaked the Qi charging standard so that Apple Watch only works with its own chargers“). Interestingly, the furniture company IKEA is selling Qi transmitters and receivers (http://www.ikea.com/us/en/catalog/categories/departments/wireless_charging/). To my surprise, when I visited a nearby IKEA store yesterday, the older iPhone and Samsung Galaxy S4 (VITAHULT) Qi receivers were on sale for CHF 0.95 (about US$1): what could be wrong with buying a few of them? At this point, I should probably mention the ‘rolling eyes’ of my wife ;-).
The question is: can I use these for my projects? So I decided to open up the wireless phone cover. The cover has to plastic parts, and with a bit tweaking I was able to separate them. Insider there is the battery connector, the receiver circuit and the charging coil under a black FFDM (Flux Field Directional Material):
The FFDM is a high magnetic permeability and low energy loss material which enhances the power transfer efficiency. The FFDM can be easily removed. Under the FFDM there is the receiver coil:
The coil is glued to the plastic cover with a double side adhesive tape. I used a tooth pick to carefully lift it up:
Same approach for the board. Removing the board was a bit more difficult, the board is very thin and I did not want to damage it. At the end, both the coil and the board were separated from the back cover:
iPhone 4/4S Receiver
The above Samsung S4 receiver is rated up to 650 mA charing current. They had the iPhone 4/4S on sale for CHF 0.95 too which can charge up to 1000 mA:
Opening that case is best from the backside:
The coil is a larger one, and the receiver electronics are shielded with a piece of FFDM (?). As the coil is too large for the Hexiwear, I’m continuinig with the Samsung S4 receiver and coil.
Attaching Power Wires
I removed the battery connector from the receiver board and soldered wires to connect the Hexiwear docking station PCB (5V and GND to the battery charging circuit):
And voilà: I’m able to charge the device 🙂 :
3D Printed Enclosure
The next step is to put everything in a 3D printed enclosure:
And is charging (not the charing icon on the Hexiwear) 🙂
IKEA Charging Station
Best of all, it works with the IKEA Qi charging station too:
Yes, that works too: 🙂
Sometimes a quick IKEA shopping can turn into something very useful outside the normal furniture world: I’m now able to use wireless Qi charging for the Hexiwear :-).
Happy Charging 🙂
PS: A big ‘thank-you’ to my wife and daughters. They fully understand what it means to have an engineering family member. Well, at least most of the time….
- Qi Charging station: Qi Wireless Charging Transmitter with 3D Printed Enclosure
- Apple iWatch charger: Apple tweaked the Qi charging standard so that Apple Watch only works with its own chargers
- IKEA Wireless chargers: http://www.computerworld.com/article/2956383/mobile-wireless/review-ikea-wireless-charging-furniture-is-stylish-and-functional-but-not-without-issues.html