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Motorcycle  Crash  Detection  and  Alert  System  Zack  Stein  April  1,  2013  

MCEN  5228:  Microsystems  Integration  Mechanical  Engineering  Department    University  of  Colorado  at  Boulder  

Boulder,  CO  80309

ABSTRACT:  There   is   a   large   void   in   post-­‐crash  motorcycle   emergency   alert   systems.  My  project  focuses  on  designing  a  system  that  will  integrate  many  components  into  a  life  saving   accelerometer   system   for   a  motorcyclist   unfortunate   enough   to   be  involved  in  an  accident.    PROJECT  DESCRIPTION:  Motorcyclists  are  35  times  more   likely  to  experience   a   fatal   accident   than  passenger  vehicle  operators.1  With  such  a  high  number  of  accidents  per  year,  safety  is   a   critical   concern   for   many   riders.  Studies   have   shown   that   decreasing   the  response   time   for   emergency   services  increases   chances   for   survival   by   a  significant  margin.2  Currently   the  market  

for   motorcycle   safety   equipment   is  saturated  with  helmets,  jackets,  and  other  protective  articles  of  clothing.  My  project  attempts  to  fill  a  void  with  life-­‐saving  post  

                                                                                                               1  (MotorcycleAccident.org,  2013)  2  (Blackwell  &  Kaufman,  2002)  

crash   technologies.   Current   post-­‐crash  technologies   only   sound   sirens   and  flashers   that   would   not   be   helpful   in   a  rural   location.3  I   have   found   no   current  systems  that  contact  emergency  response  personal  via  the  cellular  network.      My  idea  for  the  microsystems  project  is  to  create   a   system   of   accelerometers   and  microcontrollers   that   will   do   two  important   life-­‐saving   actions.   First   the  system   would   monitor   the   acceleration  readings  from  each  of  the  accelerometers  ensuring   that  no  high-­‐g  accelerations  are  detected   like   those  seen   in  a  crash.   If   the  system   senses   a   high-­‐g   acceleration,   an  emergency  signal  would  be  sent  out  via  a  GSM   connected   module   or   through   ones  smartphone.   The   other   key   aspect   to   the  system  would   be   usage   of   the   individual  accelerometers   to   alert   the   emergency  response   teams   of   any   possible   injury  locations   due   to   high-­‐g   accelerations   at  specific  locations  around  the  rider’s  body.  This  system,  along  with  a  standalone  GSM  module   or   smartphone,   could   help  revolutionize   emergency   response   for  accidents.    DESIGN  IDEAS:  After   researching   available   options   for  semiconductor  chips  and  microsystems,   I  have   found   that   this   project   is  significantly   less   about   designing   a   new  

                                                                                                               3  (Limelite  Inc  ,  2013)  

Figure  1-­‐Image  depicting  a  motorcycle  crash  

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stand-­‐alone   system   than   it   is   about  integrating   multiple   already-­‐available  systems.   The   following   is   a   list   of   the  possible  components  that  will  be  required  to  create  a  functioning  system:    Arduino  GSM  Shield4  

 This  circuit  board  allows  for  a  stand-­‐alone  Arduino  board   to  be   connected   to  a  GSM  network   with   the   usage   of   a   SIM   card.  This   board   is   the   alternative   to   using   a  smartphone.    Arduino  Micro5  

 While   there   are   many   options   for  microcontrollers   and   development  boards,   I  chose  the  Arduino  Micro  due  to  its   relevantly   easy   user-­‐interface,   small  size,   and   high   number   of   inputs   (20  digital  and  12  analog).  6  This  should  allow  me  to  design  a  system  with  a  high  number  of   accelerometers   while   keeping   the  system  small  and  lightweight.    ADXL377:  3-­‐AXIS  ACCELEROMETER7  

                                                                                                               4  (Dangi  internet  Electronics  S.L.,  2013)  (Dangi  internet  Electronics  S.L.,  2013)  5  (Dangi  internet  Electronics  S.L.,  2013)  6  (Dangi  internet  Electronics  S.L.,  2013)  7  (Analog  Devices,  2013)  

   

The   ADXL377   is   a   high-­‐G   accelerometer  that   has   been   used   in   Indy   car   safety  systems   for   many   years. 8  Since   it   has  proven   successful   in   Indy   car   safety  systems,   I   know   that   such   an  accelerometer   would   work   for   my   crash  detection  system.   I  also  chose  this  device  due  to  its  relatively  low  weight  as  well  as  the   cost   at   $4.79   each,   when   purchasing  in  bulk.    BLE   Mini   Bluetooth   4.0   iPhone  module9  

 The  above  module  would  replace  the  GSM  board   in   my   design.   While   I   feel   that  having   a   standalone   board   would   be  better   for   crash   survival   as   well   as   low  power   consumption,   I   am   realistic   with  the   market   moving   towards   smartphone  apps  and   integration.  This  module  would  allow   my   Arduino   Micro   to   relay  information   to   a   smartphone   application  that  could  monitor  the  data  in  real-­‐time.      Design  Conclusion:  

                                                                                                               8  (Analog  Devices,  2013)  9  (Red  Bear  Company  Limited,  2013)  

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These  components  are  basic   components  that   could   fill   the   roles   required   to  develop   a   crash   detection   system   for   a  motorcycle.   With   the   pieces   laid   out,   I  foresee   a   product   being   developed   that  could   hit   a   $200   price   point.   For   a  prototype   system,   the   cost   for   a   10-­‐accelerometer   system   would   be  approximately  $150.    KEY  ANTICIPATED  ISSUES:  While   the   majority   of   the   components  have   already   been   developed,   I   feel   that  the   biggest   challenge   to   develop   a  successful   product   will   be   integration   of  the   components.   While   each   individual  component   is   small   and   low   power,   the  system   must   be   interconnected  throughout  the  person’s  clothing  in  order  to  be  fully  effective.  This  will  require  well-­‐engineered  solutions  in  order  to  maintain  comfort  and  usability.     I  plan   to   focus  on  creating   a   user-­‐centered   design   that   is  both   intuitive   and   follows   Apple’s  philosophy  of  just  working.    Besides   the   engineering   required   to  integrate   each   of   the   components   into   a  system,   I   can   also   anticipate   a   single  integrated   circuit   board   that   would   hold  all  components  minus  the  accelerometers.  It   is   possible   to   integrate   the  accelerometers,   however,   the   injury  pinpointing   would   be   lost.   A   more  cohesive   design   for   the   individual   chips  would   significantly   reduce   the   cost,  power   dissipation,   and   size   of   the  product.   Another   major   issue   that   I   will  face   in   the  creation  of   this  product   is   the  algorithms  used  to  detect  whether  or  not  a   crash   event   has   occurred.   Due   to   the  nature   of   the   accelerometer   mounting  locations,   each  accelerometer  will   have  a  different   substrate   with   which   it   is  mounted.   As   a   result,   the   acceleration  values   seen   on   an   individual  accelerometer  may  not  detect  a  crash.  My  

plan   is   to   create   this   algorithm   using   a  trial   and   error   method   by   mounting   the  system  to  actual  motorcycle  equipment  in  order   to   find   acceleration   values   for  various  locations  around  the  body.  In  the  next   semester   I   plan   to   apply   for   an  EEF  grant   in   order   to   bring   this   project   into  reality  and  allow  me  to  purchase  test  gear  and   electronics.     I   anticipate   that   my  system  will  be  extremely  useful  in  helping  to  mitigate   some  of   the   risks   involved   in  travel  by  motorcycle.      ANALYSIS  When   contemplating   the   future   of   this  system,   I   chose   to   focus  on   the   two  most  important  aspects  in  order  to  create  a  real  prototype   as   quickly   as   possible.   I   first  chose  to  analyze  a  method  for  integration  into   current   motorcycle   equipment.   In  order   to   fit   all   of   the   required  

electronics,  I  chose  to  take   advantage   of   a  currently   unused  volume   on   riders  backs   called   the  speed   hump   as  seen   in   Figure   2.  This   space   is  

currently   empty  being   supported   by   a  piece   of   curved  plastic.   My   design  takes   advantage   of  this   space   by  

integrating  everything   into   this  volume   including   the  GSM   module,   the  

Arduino  microcontroller,   and   the   battery.   These  components  will  be  protected  in  a  plastic  shell  in  the  event  of  a  crash  on  the  rider’s  back.   I   began   by   creating   a   shell   that  would   fit   in   this   area.   After   determining  

Figure  2-­‐Motorcycle  Suit  with  Speed  Hump  

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CAD  LAYOUT  • Arduino  Micro  is  the  central  

component  in  green  • Arduino  GSM  is  the  red  

component  • The  Battery  is  the  blue  

component  • The  accelerometer  is  the  

small  black  component    •

the   volume   that   I   had   to   work   with,   I  created  simple  CAD  models  for  each  of  the  components  as  seen  in  Figure  3.  The  blue  

component   is   the   single   most   important  component   for   creating   a   successful  product,   the   battery.   I   chose   to   further  analyze   the  battery   life  as   it   is   the  key  to  creating   a   system   that   can  work   for   long  periods   of   time   without   user   charge.   I  began  my  analysis  by  focusing  on  current  battery   technology   and   their   energy  densities.   I   chose   to   use   the   iPhone   5  battery   as   my   benchmark.   The   iPhone’s  battery   has   dimensions   of   82.3mm   x  31.3mm   x   3.9mm 10 .   When   combining  with   the   total   charge  of  1440  mAh  at  3.8  Volts11,   I   found   that   this   battery   had   a  density   of   1.4334   x   108   mAh/m3.   Now                                                                                                                  10  (r2shyyou,  2012)  11  (GSM  Arena,  2013)  

that   I   had   the   battery’s   power   density,   I  found   the   total   discharge   rate   for   the  system.  I  used  average  rates  for  all  of  the  modules.   It   should   be   noted,   that  depending   on   the   demand   of   both   the  GSM  module  and  the  microcontroller,  the  power  usage  could  be  significantly  higher  than  my  calculated  value.  Due  to  this  fact,  I  increased  the  battery  volume  in  order  to  provide   more   space   for   the   battery.  Within   the   power   loss   calculations,   I  included   power   loss   through   conductive  threading  which   I   plan   to   use   to   connect  all   of   the   accelerometers   to   the   central  system.   The   total   anticipated   power  dissipation   for   the  system  was  calculated  to   be   156  mA.   The   components   included  in   this   calculation  were   the  GSM  module,  Arduino   microcontroller,   twelve  accelerometers,   and   twenty   feet   of  conductive   threading.   The   final   step   in  analyzing  the  theoretical  life  of  my  device  was   determining   the   volume   of   the  battery.  Using  Solidworks  sensors,  I  found  that   the   blue   battery   in   Figure   3   has   a  volume   of   243.5   cm3.   To   put   this   into  perspective   a   standard   non-­‐replaceable  battery  for  a  Macbook  Pro  has  a  volume  of  276   cm3   so   my   battery   is   a   definitely   a  manufacturable   volume 12 .   Using   the  iPhone  5’s  battery  power  density  found  in  combination   with   the   volume   of   the  battery  and  the  total  power  dissipation,   I  found   that   my   system   would   be   able   to  operate   for   approximately   225   hours.  While   this   is  most   likely   an  overestimate  of  the  true  life  of  the  system,  it  allows  me  to   get   an   estimation   for   the   current  design.  When  creating  a  prototype  of   the  system,   I   plan   to   use   off-­‐the-­‐shelf   laptop  batteries   to  power   the  device.  These  will  be   approximately   the   same   size   and  weight  as  the  current  design.                                                                                                                      12  (Amazon,  2013)  

Figure  3-­‐Inner  Layout  for  System  

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CONCLUSION  A   system   similar   to   the   one   described   in  this   report   would   allow   motorcycling   to  become   significantly   safer   by   allowing  emergency   services   to   locate   a   downed  rider.   I  hope  that   I  will  receive  a  grant   in  the  coming  months  in  order  to  implement  a  prototype   that   could  end  up  saving   the  lives   of   thousands   of   individuals.   While  upcoming   technologies   will   create   an  even   more   impressive   system,   the  technology   is   currently   available   to  implement   the   motorcycle   safety   system  today.        MATLAB  CODE  close all clear all clc x=82.3/1000; %m http://forums.macrumors.com/showthread.php?t=1497391 y=31.3/1000; %m z=3.9/1000; %m volume=x*y*z; %m^3 total_power=1440; %mAh power_density=total_power/volume %mAh/m^3 battery_voltage=3.8; %V http://www.cowae.com/the-iphone5-multi-charger-battery-components-exposure-capacity-1440mah-voltage-3-8v.html arduino_GSM=100; %mA peaks at 2A with standby at 1.5mA http://imall.iteadstudio.com/im120417009.html arduino_micro=50; %mA http://arduino.cc/en/Main/ArduinoBoardMicro accelerometer=0.3; %mA http://www.analog.com/en/mems-sensors/mems-accelerometers/adxl377/products/product.html thread_resistance=300; %Ohm/Foot https://www.sparkfun.com/products/8544 thread_length=20; power_required=arduino_GSM+arduino_micro+accelerometer*12+battery_voltage^2/(thread_resistance*thread_length)*1000 %mA %charge time for a single iphone battery charge_life=total_power/power_required; %hours %determine battery size based on time required desired_hours=25; battery_size=power_required*desired_hours/power_density;

%determine battery life off of solidworks model current_design_size=14.86*0.000016387 % m^3 design_time=current_design_size*power_density/power_required total_power=current_design_size*power_density

Works  Cited:  Amazon.  (2013).  MacBook  Pro  15  inches  Unibody  Battery  

A1321  -­‐  661-­‐5211,  661-­‐5476.  Retrieved  April  30,  2013,  from  Amazon:  http://www.amazon.com/MacBook-­‐inches-­‐Unibody-­‐Battery-­‐A1321/dp/B0044EKJDQ  

Analog  Devices.  (2013).  ADXL377:  3-­‐AXIS  HIGH  g  ANALOG  MEMS  ACCELEROMETER.  Retrieved  April  4,  2013,  from  Analog  Devices:  http://www.analog.com/en/mems-­‐sensors/mems-­‐accelerometers/adxl377/products/product.html    

Blackwell,  T.  H.,  &  Kaufman,  J.  S.  (2002,  April  9).  Response  time  effectiveness:  comparison  of  response  time  and  survival  in  an  urban  emergency  medical  services  system.  Retrieved  April  4,  2013,  from  PUBMED.GOV:  http://www.ncbi.nlm.nih.gov/pubmed/11927452  

Dangi  internet  Electronics  S.L.  (2013).  Arduino  GSM  Shield  (integrated  antenna).  Retrieved  April  4,  2013,  from  Arduino  Store:  http://store.arduino.cc/ww/index.php?main_page=product_info&cPath=11&products_id=244  

Dangi  internet  Electronics  S.L.  (2013).  Arduino  Micro.  Retrieved  April  4,  2013,  from  Arduino  Store:  http://store.arduino.cc/ww/index.php?main_page=product_info&cPath=11&products_id=245    

GSM  Arena.  (2013).  Apple  iPhone  5.  Retrieved  April  29,  2013,  from  GSM  Arena:  http://www.gsmarena.com/apple_iphone_5-­‐4910.php  

Limelite  Inc  .  (2013).  Crash  Alert:  Emergency  Response  System.  Retrieved  April  4,  2013,  from  Crash  Alert:  http://www.motorcyclecrashalert.com/  

MotorcycleAccident.org.  (2013).  Motorcycle  Accidents  Statistics  And  Possible  Causes.  Retrieved  April  2,  2013,  from  MotorcycleAccident.org:  http://www.motorcycleaccident.org/motorcycle-­‐accidents-­‐statistics-­‐and-­‐possible-­‐causes/  

r2shyyou.  (2012,  November  27).  iPhone  5  battery  dimensions  (LxWxH)?  Retrieved  April  29,  2013,  from  Mac  Rumors:  http://forums.macrumors.com/showthread.php?t=1497391  

Red  Bear  Company  Limited.  (2013).  BLE  Mini.  Retrieved  April  4,  2013,  from  Red  Bear  Labs:  http://redbearlab.com/blemini/