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The Science bit explained.......

How it Works

Sentry, is normally plugged into a convenient mains power socket.



The unit is activated by the user logging on to the Sentry Web Site and activating a monitoring plan.

Sentry then automatically activates and connects to the mobile phone network (GSM).



Sentry comes with a pre-installed ONE-WORLD Sim. That means you don't need a local mobile phone contract to use Sentry. 



You set Sentry up via the Sentry Web site ,and set the alert parameters that interest you, namely:



  • presence or absence of mains power,
  • the lowest or highest temperature,
  • or the humidity range.

Sentry then monitors those parameters, when any of them are exceeded, Sentry will alert you , via the Sentry Web server and send a message to you via SMS ( Text), eMail or a Twitter message.



You can also interact with Sentry using a custom Sentry App for your smartphone too.



It couldn't be simpler, no wires, no phone contracts, works in over 50 countries worldwide. including  US, UK , EU ( 110Vac/230Vac)

Sentry, monitors your environment, when you can't be there.

​Click diagram to see a larger image.

Sentry requires a valid  GSM mobile network signal to operate. Note you can test if you have a signal where you want to put Sentry by using your own mobile phone.

The Internet of Things


The  Internet  started  out  as  a  basic  mechanism  for  connecting  large  computers  and  sharing  data. Its underlying architecture and its technology is designed to primarily support this aim.  But  the  Internet,  aided  by  more  and  more  users  being  connected  every  day,  has  rapidly  evolved  beyond  its  original  concepts. 

Today  and  increasing  into  the  future,  more  and  more  forms  of  communication  will  be  carried  over  the  Internet.  Users  are  and  will  expect  to  connect  all  forms  of  electronic  devices,  often  those  not  traditionally  associated  with  the  Internet.    Smartphones,  cameras,  Internet  connected  TV,  security  systems,  etc  are  all  using  the  Internet  as  a  means  of  communication,  either  betweens  devices  or  to  connect  users  with content (alarms, video, audio, messages etc.).

This  “Internet  of  Things”,  a  concept  of  uniquely  identifiable  objects  all  connected  to  the   Internet has  been  around  for  some  time.    However  recently  a  number  of  key  factors  have   led  to  growing  Internet  connectivity: 

  • Widespread  penetration  of  the  Internet
  • Familiarly  amongst  the  ordinary  public
  • Cost  of  technology  to  connect  to  the  Internet  has  fallen
  • Smartphones  –  User  has  24/7  connectivity
  • 3G  (and  now  4G)  mobile  Internet  connectivity,  WiFi,   The  Internet  is  everywhere

We  have  now  arrived  at  a  conjunction  of  user  expectation  and  technology,  the  events  in   peoples  lives  are  communicated  to  them  via  the  Internet  and  in  particular  made  available   via  web  browsers  and  mobile  devices.    Witness  the  popularity  of  “real  time”  bus,  train  and   airline  information  fed  to  the  user  directly. 



This   Internet   of   Things,   is  where   Sentry   is   positioned.   This   is   a   simple   device   that   allows   users  to  monitor  simple  environmental  parameters  and  have  that  status  forwarded  to  them   via  email,  text  and  twitter  feeds.

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