Transcript of Bluenanny Tot
Always an eye on the children by
BlueNanny Bluetooth-based assistant nanny
SRI KRISHNADEVARAYA UNIVERSITY
COLLEGE OF ENGINEERING&TECHNOLOGY
Blue Nanny has applied today’s technology to introduce a new dimension to child minding at home. It provides constant awareness of children with the integration of latest technologies. With the application of Blue Nanny (Bluetooth-based assistant nanny) there is always an eye on the children. Child safety at home has been identified as one of the most important issues that concern parent. On the average home is responsible for the highest number of injuries amongst young children. Due to the busy lifestyle of today’s parents, continual supervision of their children can sometime be demanding.
Blue Nanny, is a home-use system developed to always keep an eye on the children at home. Blue Nanny is a complete wireless system created to assist child minding and reduce the risk of child injury at home. It uses both Bluetooth technology and proprietary RF communica -tion to provide parents with an instantaneous voice communication link to their child with constant awareness of their child’s location. It will alert the parent when children come close to potential dangers. Blue Nanny consists of portable modules to be worn by parent and child. Hardware for these modules will entail voice signal conversion and user interfaces constructed for compatib -ility with Bluetooth communication. The design of RF beacons employs the use of a grid-based environment in the home.
We also present the limitations of some commercially available products
which focus on child monitoring like Digital Angel and Kid bug with Blue Nanny including the
PERFORMANCE REQUIREMENTS, DESIGN METHODOLOGY and INNOVATIVE FEATURES
of Blue Nanny And finally conclude the presentation with few ideas to improve the current version of the wireless communica -tion use in the Blue Nanny system
NEED AND BACKGROUND IDEA:
In today’s marketplace, other similar competitors of the electronic child monitoring system are available. Two of the more common systems are the Digital Angel and Kid bug.
The Digital Angel consists of a bio-watch and beeper styled communication-tracker device. Digital Angel works well in outdoor scenarios, with Global Positioning System (GPS) technology used. The watch style tracker provides the location and condition of the wearer
Digital Angel System
The caretaker will be notified of any emergencies occurring to the wearer by the Digital Angel Operating Centre. These
notifications can be transferred to either the caretaker’s mobile phone or their Personal Digital Assistant (PDA). Although this device provides an accurate whereabouts of the wearer, it targets more to adults and seniors in society who require mental and physical health care. It will give the caretaker access to the wearer.s realtimecondition. If it was to be worn by a child,it would not educate the child of potentialdangers in the environment. Hence, doesn.tassist in preventing accidents, more to assistafter an accident has occurred. It also does not allow the parent to contact their child and interact via voice, therefore not giving the child a sense of security and comfort
The Kid bug was derived from the success of Car Bug. Kid bug is a plan to allow tracking of a child’s location through a bug on the child’s clothes. It uses mobile cell technology to gain access to the GPS network to find the satellite location of your child. A subscription to the network and a mobile phone is all that is needed for the caretaker to have an immediate and accurate location of your child. Although, Kid Bug also fails to prevents children from accidents. It will not allow any interaction with between parent and child. This system is only required when a child is lost therefore no education of the child’s misbehavior is recognized.
Blue Nanny succeeds where other systems fail. It will educate children of potential dangers, allow parent to setup their personal configurations and provide complete awareness of their child.
The Blue Nanny System
Blue Nanny is a wireless Bluetooth -based solution to assist in child minding. It is a system designed for the supervisory user
such as a parent or guardian, to supervise children in a domestic environment when they are out of sight. After outlining the main reason for injuries with young children, Blue Nanny aims to help prevents such injuries. It operates by providing parents immediate alerts when their child is in a dangerous area. Blue Nanny will detect the location of children and provides the parent this information for their utilization. The parent has the option to respond to the alerts and/or contact their child through the wireless two-way voice communication that Blue Nanny provides. Blue Nanny will succeed to provide constant child awareness to allow peace of mind for any parent.
The Blue Nanny system provides parents with information regarding the locations of children by visual and audible alerts. It uses both Bluetooth technology and proprietary Radio Frequency (RF) communication as a means of wireless communication between modules. Alerts can occur if any of the children in the system moves within proximity of an unsafe or restricted area that is predetermined by the user.
System operation begins with the
user placing units with embedded RF beacons, called EyeMods, in selected child minding regions within the home. There are three different classes of EyeMods that Blue Nanny provides:
The Local Eye,The Point Eye and The Smart Eye.
The Blue Nanny innovative features are:
● Detect children (and notify parent) if a child enters an area where potential dangers are already identified.
● Notify parent if a child leaves a predetermined area. ● Detect extreme temperatures in surroundings and notify parent if determined that potential danger exists. ● Educate children about potentially dangerous household areas. ● Provide a two-way phone quality voice communication. ● Offer adjustable levels of child minding possible demanded by changing parental focus (i.e. age of a child, changing environment). ● Support the need for children to learn their boundaries while not strictly confining them.
Blue Nanny is configured using the Blue Nanny Application Software (BlueNApp). The system configuration data is transmited wirelessly via Bluetooth to a parental unit, called ParentMod. The children carry units called ChildMods which dynamically configures from the ParentMod. The EyeMods uses a 433.93 MHz RF signal to Communicate to the ChildMod when a child enters an EyeMods region. Bluetooth technology is used between ParentMod and ChildMod to establish simultaneous data and voice communication. Bluetooth allows for a secure and wireless connection
There are several performance requirements that Blue Nanny aims to fulfill. Blue Nanny must first meet the functional requirements whilst maintaining user . Friendliness in operation. A child’s safety depends largely on a fast system response time, which can be achieved by real-time data and voice processing. A secure connection between the ParentMod and ChildMod is vital in preventing intruders from eavesdropping. The BlueNApp system software must provide security in order to
avoid other user tampering with the systems configurations. This is achieved by and authorization log-on screen which will database personal settings for each user. The ParentMod, ChildMod and EyeMods are all batteries powered. Therefore, low power consumption is required, to ensure long battery life. As the ParentMod and Child Mod are designed to be portable and wearable units, they need to be robust, compact and lightweight.
Blue Nanny Block Diagram
The project consists of the following modules: BlueNApp software, ParentModHardware, ChildMod Hardware, Bluetooth communication and RF communicationModules. The module designs were specified in respect to product accessibility and developed from the user’s perspective to optimize the product application, capability, price and performance. These include choosing a standardized system voltage level at +3V DC to comply with Bluetooth, which helps to attain low power consumption levels for the system. One major constraint encountered which altered the design of the system was the current
indoor navigation technologies. The Bluetooth module will not give accurate separation distance between another Bluetooth module. To overcome this difficulty, EyeMods were designed to act as beacons in a grid arrangement. If the grid was pre-defined, any point within the grid will therefore have a location with-respect-to the grid arrangement.
Innovations and Uniqueness:
Blue Nanny allows parents to always keep an eye on more than one child at different places at once The uniqueness of Blue Nanny lies in its ability to integratetechnologies such as Bluetooth and RF communications in child safety preventionschemes. Additionally, Blue Nanny has other unique features such as knowing when a child has left the detectable range or removes their ChildMod. Configuration of the system is user-friendly with a well designed interface and wireless data exchange between the modules. The user does not need to manipulate hardware during the setup.
The Blue Nanny Codec
For Bluetooth voice communication, the use of a voice codec is required. A codec(codec-decoder) is used to convert an analog signal into a digital stream. As voice is ananalog signal a device know as a voice codec can be used to convert this signal into a digitalstream to allow digital transmission. Once voice is digitized, it may betransmitted long distances without degradation. A codec is a single device that does both the Analog-to-Digital and Digital-to-Analog conversions. Voice communication between the ParentMod and ChildMod allows immediate interaction between the parent and child. This provides the parent, a direct connection to the child in order to maintain
constant awareness and to give any reassurance desired.
Blue Nanny Product will consist of the Ericsson 101 007 Bluetooth ROK module which provides the Bluetooth connection between parent and child modules. Since the Ericsson Bluetooth modules supports synchronous voice data transmission (SCO link) a pulse code modulation (PCM) codec chip was used to transmit voice signals between the parent and child modules. There are Jumpers. located on the Bluetooth Module to get convenient access to the SCO link.
This Bluetooth module performs voice data compression, which results in a smallerbandwidth utilization and better sound quality. Selection of the Codec chip wasdecided upon many factors such as operation voltage and bit resolution. The MotorolaMC145483 13-bit linear Pulse Code Modulation (PCM) Codec9 is used in the design of this system since it meets most requirement for compatibility with the Bluetooth module. The codec can operate from the +3.3V powers supply produced by the PCM .Jumpers. (pin 6). It accepts a linear, 2s complement digital input data using Mu-Law compression which will be all produced by the Bluetooth Module. As well as, the bit rate synchronization clock, also sourced by the Bluetooth Module The PCM algorithm is one of many approaches used to digitize a voice signal.
The basic feature of Motorola’s MC145483 PCM algorithm is that a voice frame is sampled 13 times by a clock that is provided by the Bluetooth Module. Each voice frame is synchronized by the Bluetooth Module’s PCM_SYNC pin which outputs an 8 kHzClock. Therefore this means that the analog input signal is sampled at a rate of 8000times per second with a 13-bit sample bandwidth. Each sample is then sign-extended to 16-bit long as required by the receiving Bluetooth device. The frame is sampled at a fixed time interval between 32 to 512 times the 8kHz frame synchronizing clock (256- 4096kHz) and is internally stepped down to 256kHz by the codec for all Analog-to- Digital operations.
PCM algorithm sampling
Each sample bit is clocked from the Bluetooth’s PCM_CLK pin which provides a 2.048MHz clock signal needed to drive PCM bits stream out on the data transmit (DT) pin of the codec. This audio bit stream is routed to the PCM_IN input of the Bluetooth device and is then transmitted to other Bluetooth module through an established SCO connection.
Upon receiving the PCM audio data, the receiving Bluetooth module must first convert the digital voice stream back to an analog signal before producing voice through a speaker. The Motorola MC145483
codec also supports this decoding method. The PCM data, received from the PCM_OUT interface of the Bluetooth Module is transferred to the Motorola codec through its DR input pin. This transfer operation timing is kept consistent with the synchronization of the frames and clocking of the data bits which are controlled by the PCM_SYNC and PCM_CLK of the Bluetooth Module, respectively.
The codec also requires a master clock signal for correct operation. This signal will be applied to the Master Clock pin (MCLK) of the codec. This pin will automatically accept a 256, 512, 1536, 1544, 2048, 2560, or 4096 kHz clock pulse and will internally step down this pulse to a 256 kHz clock. This clock will provide sequencing signals for internal filters and amplifiers. In the Blue Nanny prototype the JITO-2 oscillator11 is used to supply a 1.544Mhz clock signal. This external clock oscillator is necessary to overcome the inability of the PCM_CLK to provide a continuous clock signal for the codec. It will be used to generate sequencing signals needed by the internal filters. Using an external clock oscillator will allow the codec’s internal timing to be clocked tokeep it operating properly.
Finally, discrete external circuitry is required for operation of internal operationalAmplifiers. This circuitry can adjust the amplification gain of the input and outputanalog signals.
Motorola Codec Pin-out
EyeMods are battery operated radio frequency (RF) beacons which are used to transmit their EyeMod ID (EID) to any receiving ChildMods in proximity. The EyeMods will be place through-out the home to regions which the parent desires supervision. Each EID will therefore be designated to the region where the EyeMod is located which will interpret the location, of the ChildMod, with respect to the home. The three classes of EyeMod are: Local Eyes, Point Eyes and Smart Eyes. The signal range of a Local Eye is approximately a 3m radius. These are typically used for general location information of child and placed in an open area. The Point Eyes have a signal range of approximately 1m radius. They are typically placed near dangerous objects or in small confined areas in the home, for example pool gate or expensive vase. A Smart Eye additionally contains a temperature sensor and would characterist -ically be used in temperature influenced environments such as the fireplace, stove, etc. the following figure illustrates EyeMod positioning around the home.
Eyemods employed in a BlueNanny Environment
Inside the EyeMods
Each EyeMod contains a micro controller and RF circuitry with the SmartEye having also a temperature sensor.
The selected microcontroller for the Blue Nanny EyeMods is the PIC16F627 from Microchip. The PIC16F627 is a memory efficient microcontroller (1k Program Memory) and inexpensive solution. It has a low power consumption (15uA) whilst being compatible to operate from a +3V battery supply. The nRF401 433.92MHz RF transceiver from Nordic provides the wireless communications between EyeMod and ChildMod. The microcontroller’s Universal Synchronous Asynchronous Receiver Transmitter (USART) interface will be used for communication with the nRF401 transceiver. The PIC16F627 onboard comparator is used to indicate a low voltage level warning for all EyeMods. By internally setting a reference voltage at +2.5V, the +3V battery supply will be continually checked against this reference voltage and will alert users by flashing a LED if the voltage was to fall below. All EyeMods are powered from 2×1.5V AA batteries.
RF specifications and selectionThe Nordic nRF401 is a true single
chip UHF transceiver designed to operate in the. 433.93MHz ISM (Industrial, Scientific and Medical) frequency band. It featuresFrequency Shift Keying (FSK) modulation and demodulation capability. The nRF401operates at bit rates up to 20kbit/s. The nRF401 was decided upon as it was compa -tible with the battery supply voltage level of +3V and was supplied with comprehensive support to make them operational. Initializing the nRF401 will require the transceiver to be placed in transmitting mode. This is accomplished by enabling the transmitter enable pin (TXEN = pin 19). The transmission channel must also be set. Channel 1 will be used for the EyeMods which transmits at frequency of 433.93MHz.
RF Transceiver and Microcontroller Interface
The nRF401 transceivers are controlled by the PIC16F627 through its USART capabilities. As they will only be required to transmit the EID, setting up the receiver side will not be needed. USART works by transmitting bytes through the TX pin (pin 8) asynchronously from the PIC16F627. This is accomplished after bits have been shifted serially into the USART buffer. On detection of a full buffer, the buffer data will be serially clocked through the TX pin. The Transmit Shift Register Status bit (TRMT) will play the role of a busy flag by going high on detection of an empty buffer. Using this bit as a buffer status bit will avoid corruption of bytes. Before the data is transmitted through the nRF410 transceiver, the data is passed through a Schmitt trigger due to USART supplying an inverted output.
When setting up the packet format for the EID, the packet is 5 bytes long and must begin with a preamble. The suggested preamble by the nRF401 datasheet is 2 bytes. The third and four byte in the packet will be used to indicate the start of the packet. The fifth and final byte of thepacket will contain information about the EyeMod.
Enhancements can be made by adding an extra byte for the EyeMod ID if more than 16 EyeMods are used. The Parity Bit will provide error checking to detect any bit errors occur after transmission.
RF Antenna Design
The EyeMods in the Blue Nanny system all use Omni-directional antenna design. Due to the large range obtained from properly tuned antennas, a single wire design proved sufficient with-respect-to range. Therefore a 5cm long dipole antenna transmitted successfully at a range of 3m, adequate for use on the Local Eyes. The Point Eye and Smart Eye only require a transmission range of 1m to which a 1cm long dipole antenna is adequate. The antenna pattern will diverse in all directions. Shielding of the antenna can allow transmis -sion in one direction. Generally, the omni-directional radiation pattern isrecommended.
Transmitting the EyeMod Identification
At 2.4kbits/s, it takes approximately 420µs to transmit one bit. It therefore takes 17ms to transmit an EID. In order to prevent the RF signals that are transmitting from
different Eyes from colliding with each other, each packet is transmitted at times set by a random number generator create from software. This is based on transmitting at intervals of one second, which is generated each time by the PIC16F627 using a random offset. This gives 60 available transmission slots that a 17ms EID can be sent. Therefore there is less than 0.06% chance of two EID packets colliding per transmission interval. If it does occur, there is little possibility of a collision during the next second since a random number is used for each EID transmission. The RF signal between an EyeMod and ChildMod has no line-of-sight restrictions. This eliminates restrictions when a user may wish to position an EyeMod. However, a problem may arise if an EyeMod is placed next to a wall and the wall allows the RF signal to be received on its other side. This problem is realized and a possible solution is using adjustable RF shielding on the Eye which limits the direction of the RF signal.
Smart Eye Temperature Sensor
Burns and scalds, are one of the top five nature of injury that most occurs to children16. The design of a Smart Eye incorporates the use of a temperature sensor to rectify this statistic. The Smart Eye is designed to be used in temperature influenced environments such as the fireplace, stove, etc. The Smart Eye will contain similar hardware to that of the Local Eye and Point Eye, but will also comprise of a DS18B20 1-Wire® Temperature Sensor by Dallas
ChildMod Security Band In order for the BlueNanny system to work, the child must wear the ChildMod at all times. Its purpose is defeated it the child removes their module. That is why the security band is implemented to firstly, hold the ChildMod tightly to the child.s waist,and also, to detect and alert the parent if the ChildMod is removed. This band is linedwith a thin wire which uses a pull-up resistor on one end that connects to a port pin ofthe ChildMod.s PIC16F876 microcontroller. The wire is connected to ground and creates a closed loop with the port pin when the band is connected. If this loop is broken, a pin on the PIC16F876 detects the input signal and sends an emergency alert message to the ParentMod which notifies the parent with the highest alert.
Future Development Future development of the Blue Nanny design can be implemented by different wireless communications as technology improves. Using RF ID tags, especially passive RF ID tags, as beacons could be just one solution. Passive RF tags will not need a battery power supply,
therefore no replacement of batteries will be required. Another solution could be using Ultra Wide Bandwidth (UWB). UWB technology can provide very fine range resolution and precision distance and/or positioning measurement capabilities. This technology could eliminate the need for Local Eyes as distance and location will beknown.Conclusion
Bluetooth technology is used to provide a secure, cheap and power efficient solution to child minding techniques. RF beacons are implemented into Blue Nanny to provide a reliable location method. Communication between the network of RF beacons and Bluetooth links will constantly monitor the location of a child. This proves beneficial for the supervision task and acts as an assistant to parents for their child minding responsibilities.
It delved into the development of Bluetooth voice communication and Blue Nanny module hardware and also provides the software concepts used for hardware integration. With current trends in market growth, the demand for Bluetooth applications is set to increase. With future revisions of Bluetooth increasing range andnumber of supported devices, Blue Nanny has the potential to be incorporated into large scale uses, such as in hospitals, kindergartens and retirement villages.
Digital Angel Corporation, 2002, .Digital Angel Website.,http://www.digitalangel.net
Carbug, 2002, .Kidbug Website.,http://www.carbug.co.uk/kidbug.htm
IEEE Computer Society, 2002, .CSIDC 2002.,http://www.computer.org/CSIDC/