Q&A: Smart Home, Android@Home, NFC, Bluetooth and 6LoWPAN

Questions and answers about Smart Home, Android@Home, NFC, Blueotooth and 6LoWPAN

Q&A about Smart Home, Android@Home, NFC, Bluetooth and 6LoWPAN during the event at c-base in Berlin.
Slides in upload here: http://www.box.net/shared/dhb87ifp9k7ox2o6fmil

c-base e.V.

The c-base e.V. is a non-profit organization to promote education in the areas of hardware, software and network technology. The multi-faceted non-profit organization is offering support to individuals, user groups and projects that are devoted to promoting knowledge and culture. Members of the organization were able to control the light (super troopers)  by their Android smartphones. The super troopers are using the DMX bus . The microphones for moderators and speakers were wireless as well. The vending machine offers two price levels. One price for members and one for non members. The authorisation at the vending machine has a wireless link by ZigBee to server at basement.


Android@Home of today is accessories connected by USB to Android smartphone or tablet. With the next version of Android it will support Bluetooth 4.0. Bluetooth 4.0 covers Bluetooth Low Energy as well. Android@Home is not the Smart Home. It is just connecting external hardware on USB to the Android device. To cover the smart home, a lot of technologies has to be touched. The latest Android@Home-PCBs holding 32-Bit micro controllers of Microchip with:

  • Microchip PIC32MX795F512 processor
  • 80 Mhz 32-bit MIPS
  • 512K Flash, 128K RAM
  • USB 2.0 OTG controller
  • 10/100 Ethernet MAC,
  • 83 available I/O including dual CAN controllers, LIN controller, 6 UARTS ….
  • User LED

With such a PCB it it possible to connect buses at home. Ethernet is already supported by hardware and library. Other buses like  EEBus or KNX can be adapted. The same can be done with low power radio links like with ZigBee or 6LoWPAN, where I prefer 6LoWPAN because it is licence free, open source and already on IPv6. An Android@Home-PCB with PIC32MX795F512 processor, plus interfaces to your equipment and buses at home, plus an Android tablet in a new plastic enclosure will be a inexpensive smart home terminal, where the owner can run his own software on tablet and Android@Home-PCB. The Android@Home-PCB of my own I loaned to c-base. They have already a pool of hardware where the members can access to.

Bluetooth, Bluetooth Low Energy, Bluetooth 4.0

Bluetooth includes Classic Bluetooth, Bluetooth high speed and Bluetooth low energy protocols. Bluetooth Low Energy is available as single and dual mode. Dual mode means, that Buetooth Low Energy and classic Bluetooth is supported. Dual mode will be used in smartphones, tablets and laptops. Apple already launched a new laptop supporting Bluetooth Low Energy. Single mode devices are supporting Bluetooth Low Energy only. Bluetooth LE in single mode is typical coin cell battery operated. A coin cell battery is enough. Nordic Semiconductor has shown a reference design for a proximity tag at the Bluetooth Low Energy road show. They also presented a temperature data logger at the same event. The data logger is using the IC nRF8001 and some kind of ultra low power micro controller. Applications examples you get by watching the videos listed as below.

BLUETOOTH Technology Automotive Use Case VideoBLUETOOTH Technology Consumer Wellness Use Case VideoBLUETOOTH Technology Smart Energy Use Case Video

BLUETOOTH Technology Entertainment Use Case VideoBLUETOOTH Technology Home Automation Use Case VideoBLUETOOTH Technology Security and Proximity Use Case Video

BLUETOOTH Technology Sports and Fitness Use Case Video
(Credit of pictures and videos: Bluetooth SIG)

There was a question about powering on/off classic Bluetooth in the Android smartphone and still running the Bluetooth Low Energy engine. I can expect that this is possible, but I cannot guarantee. Even if the dual mode IC is supporting that, a software bug can make it worst and allow both 2400 MHz transivers on and off at the same time. We will see what will happen.


6LoWPAN is IPv6 riding on radio wave. It is mainly UDP/IP because acknowledge handling like with TCP/IP will just block the radio channel and waste energy. 6LoWPAN is a radio protocol like ZigBee. 6LoWPAN is in comparison to ZigBee licence free and the specification is open source.  6LoWPAN is IP communication from end to end. Some 6LoWPAN radio modules supports already IPsec.  6LoWPAN can be bridged to your router. With ZigBee you need a gateway. A gateway often is a security risk. Nevertheless, there are radio modules available that can run ZigBee or 6LowPAN stack.
On the Internet you’ll find hints that Google plans to publish a licence free 6LoWPAN stack on 868 / 915 MHz, using frequency hopping by end of 2011. More about 6LoWPAN by reading the blog posts here.

Near Field Communication NFC

The most questions was on range. The range of Near Field Communication is low, because it is planned to be used for payment. The longer the range the higher is the risk that somebody can listen in. NFC is a RFID technology. A device can be a tag, a reader or both = reader and tag. A smartphone like the Google Nexus S is reader and tag. If you held two phones close together you can easily change your contacts wireless or exchange photos.
An access control system is often a reader only . The smartphone operates then as a tag for authorization or the passive key-fob is doing the same job. Key-fobs are passive. The energy will be transmitted by the reader and this energy is high enough to run the controller inside the tag and then to transmit the information stored on the tag back to the reader.

Typical range of the radio channels in an Android smartphone

Bluetooth V2.1 BLE NFC
RFID mode active active ISO 18000-3
Standardisation body Bluetooth SIG Bluetooth SIG ISO/IEC
Network Standard IEEE 802.15.1 IEEE 802.15.1 ISO 13157
Network Type WPAN WPAN Point-to-point
Cryptography available available not with RFID
Maximum range ~30 m (class 2) ~50 m ~ 0.2 m
Frequency 2,4-2,5 GHz 2,4-2,5 GHz 13,56 MHz
Bit rate 1-3 Mbit/s ~200 kbit/s 424 kbit/s
Set-up time < 6 s < 3 ms < 0.1 s
Power consumption varies with class < 13 to 23 mA (xmit) > 15mA (read)

The power consumption of Bluetooth Low Energy chips is not always equal. The IC of Nordic called nRF8001 tells 13 mA @ 0 dBm. Other suppliers tell 23 mA @ -6dbm. By a 6dB less power level they charge the double of the current! A temperature sensor or a proximity tag based on a nRF8001 will stay much longer alive then with IC of other supplier. BTW, with the coin cell batteries it is the same. Battery is not battery.

Indoor locating

The interest in indoor locating comes up in two face to face meetings. I linked the two developers together and promised to support them with further information after the show. One of my hobby-horses is locating. There are tons of stuff stored on my hard-disc. One blog post related to indoor locating is Microsofts human antenna  published here. It sounds perfect for Ambient Assisted Living (AAL). A further blog post regarding indoor locating will follow.

Smart Home, Ambient Assisted Living, Telemedicine

The Smart Home we have in our mind as long as we are young. For some people Smart Home contains the smart TVs or playing video games by wireless game controller on smartphone or tablet. It also can be the connection of the  smartphone to a sport equipment. Other people would like to save money for energy or just save our nice green planet. If you are older then the same wireless technologies will be used to create Ambient Assisted Living. Later on the same wireless technology can be a part of the telemedicine equipment you will use.

If you are interested in Smart Home, Android@Home, NFC, Bluetooth, 6LoWPAN or any kind of wireless or wired technology then you are welcome to ask for an offer for a bundle of evaluation kits that will support several technologies, including antennas and design in aid for the integrated circuits/radio modules and antennas to your product.

Just send an e-mail by using the form here or by e-mail to harald.naumann (at) gsm-modem.de

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