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i Badge V1.0. Contents: Properties Sensors Bluetooth interface Inferfacing iBadge SW development Energy monitoring Speech processing PCB / Enclosure. Presented by Ivo Locher. Aim of iBadge. Investigate behavior of children in a Kindergarten

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i Badge V1.0

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I badge v1 0


  • Contents:

  • Properties

  • Sensors

  • Bluetooth interface

  • Inferfacing iBadge

  • SW development

  • Energy monitoring

  • Speech processing

  • PCB / Enclosure

Presented by Ivo Locher

Aim of ibadge

Aim of iBadge

  • Investigate behavior of children in a Kindergarten

  • Research subject for embedded systems / position tracking / wireless networks /speech recognition

  • Basis for further applications

Properties of ibadge

Properties of iBadge

  • Speech recording / replaying

  • Position detection

  • Direction detection / estimation (compass)

  • Tilt

  • Weather data: Temperature, Humidity, Pressure, Light

Blockdiagram ibadge


Ibadge components

iBadge components

  • ATMEGA 103L- 128kB Flash, 4kB SRAM, 4kB EEPROM- 4MHz Clock, 32kHz timer- QFP package

  • DSP TMS320VC5416- 64kB DA RAM, 64kB SA RAM, Harvard- 8MHz ext. clock, up to 160MHz internal clock (PLL)- flexBGA package

Data exchange

Data exchange

  • DSP Host-Port  AVR address / data bus

  • 8Bit

  • Hardware interrupt driven

  • Host-Port enables AVR to access entire memory space of DSP

Sensor specs

Sensor specs

  • Temperature- 16Hz Fs, -55 to +125oC, 0.25 K/LSB

  • Battery current monitoring*- 16Hz, various resolutions: 0.626 – 2.44 mA/LSB

  • Accelerometer**- 10Hz Fs, +/- 2g, duty cycle

  • Microphone- 16kHz Fs, 16Bit/sample (Codec), 20kHz BW

Sensor specs cont d

Sensor specs (cont’d)

  • Position tracking (ultrasound, RFM)- 10Hz, 10cm resolution

  • Weather sensors (humidity, pressure, light)**- 400Hz, analog

  • Magnetic field*- 15Hz, +/- 6gauss, analog

  • * On board calibration / ** external calibration

Sensor specs cont d1

Sensor specs (cont’d)



  • Fc = 2.400 – 2.483 GHz

  • GFSK, BT = 0.5

  • Nominal output power = 0 dBm (1mW)

  • Frequency hopping with 79 channels

  • Approx 1Mb/s, TDMA, time slot=625 s

  • Distance: 10..30m (1mW)

Bluetooth cont d

Bluetooth (cont’d)

  • 1 Master, 7 Slaves

  • Asymmetric mode w/ 723.2kb/s downlink, 57.6kb/s uplink (ACL)

  • Symmetric mode with 433.9 kb/s (SCO)

  • 3 simultaneous synchronous voice channels with 64kb/s

Bluetooth cont d1

Bluetooth (cont’d)

  • EricssonROK 101 007

  • ARM7-Thumb

  • Programmable

  • UART used(460kB/s)


Interfacing ibadge

Interfacing iBadge

  • Connector board- RS232 connection between PC, AVR, BT- JTAG interface toDSP debugging- free RS232 from/to AVR (i.e. for a terminal)

Connector board 35x80mm

Connector board (35x80mm)

  • Top


Interfacing with rs232

Interfacing with RS232

  • 3 connections (RS232):- BT  AVR- BT  PC- PC  AVR



  • PC AVR- Download of AVR-SW and DSP-SW into Flash / EEPROM of AVR- Download-SW / cable provided by Atmel- File format: Intel HEX-File- AVR-SW runs on TinyOS- AVR boots up DSP over Host-Interface

Connection cont d

Connection (cont’d)

  • BT  PC- configuring/programming of BT interface- download of a separate program running on the BT module- sending data from PC over BT

  • BT  AVR- normal running mode of iBadge- future: programming of AVR / DSP

Sw development scenario

SW Development Scenario

  • AVR-SW development on Atmel Compiler,testing / debugging over RS232

  • DSP-SW development with TI Code Composer Studio,testing / debugging over JTAG interface

Scenario cont d

Scenario (cont’d)

  • Stand-alone version:- DSP-SW must be included in AVR-SW (as binary array, *.abs)- AVR-SW (including DSP-SW) download over RS232 interface / storing in Flash on AVR- Boot up: AVR-SW starts / keeps DSP in reset- DSP-SW download over host interface (8 Bit) - DSP releasing from reset and DSP-SW starts

Energy monitoring

Energy monitoring

  • 4 Battery monitors:- Entire circuit- All sensors- DSP- Bluetooth

  • On/off-switching of partial circuits:- All sensors- Only weather sensors- DSP- Bluetooth

Tree structure

Tree structure

Switching / battery monitors are controlled by AVR



  • Li-Ion

  • Voltage: 3.6V

  • Capacity: 700mAh (= 9kJ)

  • Approx. battery life, when everything is on all the time: 3.5h

  • estimated battery life for normal operation: 5.4h

Motivation for energy monitoring

Motivation for Energy Monitoring

  • Find optimal scheme what most energy efficient is, i.e.:- Codec:speech compression/feature extraction vs transmitted datacomputational power consumption vs radio (BT) power consumption

Motivation cont d

Motivation (cont’d)

  • Run entire or parts of iBadge in a mode, which is most energy efficient.=> duty cycle (Sung Park)

Power up

Power down



Speech processing

Speech processing

  • Implementation of different Codecs G.722 (G.729, proprietary)

  • Front-end processing of speech on iBadge

  • Seamless switching between them

    Energy efficiency / data rate / recognition rate

Codec g 722

Codec G.722

  • Output data rate: 64kb/s

  • 7 kHz analog BW

Pcb 62 5 x 47mm

PCB (62.5 x 47mm)



Pcb cont d

PCB (cont’d)

  • PCB size: 62.5 x 47mm (same width as battery)

  • 4 signal layers / 6 power planes with separate analog plane

  • 0.006” tracks / 0.004” clearance

  • Additional small board (7mm), perp. for acceleration sensor(z-axis)




Pocket clip

Finally: a customized enclosure

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