SenseSurface - Ixp Note
Girton Labs Ltd

 July 2009


Never forget an appointment! 

Time Sensitive Paper 

The paper with feeling 

Keep track of valuable objects like phones, books etc.

Prototype sticky note - Royal Mail postage stamp to show scale of microcontroller, battery and sensors

Ixp-Note is a new form of intelligent sticky note that allows the user to create time sensitive paper. 

 Tiime  and date is selected via a novel paper  touch sensitive sensesurface. The card  will light up  and ring at the chosen time.   

A novel design of power management which works like the human heart  is used to achieve very low power. 

The  Ixp-Note sensing platform starts at  coin size and can be attached to paper surfaces  and designed to be used like normal sticky notes and also to be  re-usable. They were originally  designed for people with  memory loss, e.g. Alzheimer's, but can be used all around the home and office. Ixp-notes have applications with appointment cards, e.g. dentist, doctor , car services.  They are useful as reminder stickers in the home for taking medicines, childcare  or feeding pets.  Card can be erased and rewritten with new messages.

 Battery life approx 1 year, ixpnote platform inc hardware and firmware  cost around $1. Low cost achieved due to novel connection technology.  This replaces a conventional printed circuit board (PCB) and costs < 1 cent per card. 

Image of working prototype ixp-note, entire protoype circuit is 1.2mm thin, similar to credit card. 

this includes computer, clock, battery, led piezo 

The card  is glossy and attractive, flexible, waterproof, washable,  pet proof,  and heat resistant 

The computer is normally  hidden by graphic design  but shown here to illustrate it working


Another Ixp-note  form factor is a sticky label in postage stamp style attached to important time sensitive and valuable paperwork, e.g. invoices, court appearances, car tax disc, party invites.  At last you will be able to  find important papers ringing in a pile of papers!  Companies might appreciate ixp-notes  so invoices paid on time.  The date  can be  set by scratch card tabs printed on paper, (1 day, 3 days, 1 week, 1 month, etc)  or just a pull a tab to activate battery and timer.

 Ixp-note labels  can also be attached to valuable objects using adhesive or magnets , attach to   books, mobile phones that are easily lost. The one year life battery enables the sticker to act as a location sounder. 

Finding lost property, examples are mobile phones, MP3 players,  cameras, passports, spectacles,  books  that are easily lost. An active label Ixp-note on a mobile phone can detect via it's sensors (e.g. touch,  motion , temperature and light) that a phone has not been picked up after a certain time, e.g. 24 hours.  Card will  only then then start to ring to attract attention. On picking up the  phone, sound automatically stops and is reset for another 24 hours.  A choice  of  20 synthesised ringtones are provide as audio reminders.  A paperclip sensor allows easy attachment and removal to books, papers,  etc.

3D Cad design of ixp-note  manufactured by 3D printer. It is a book clip with a leather finish.

Ixp-note can also be used for business cards - give your card to a contact asking them to contact you in a week. It might end up at bottom of a brief  case but will ring  after a week. 


We also have applications for garden plant and pet care and safety. 

Prototype ixp-note

waterproof ixp-note running code in a Cambridge thunderstorm 
click to enlarge

ixp-note immersed in wine

Has anyone fed the cat?
Put ixp-note close to kitten's bowl. Who has last feed her, Mum, Dad or Daughter? Ixp-note will make synthesised cat meow twice per day to remind family  to feed here. Timer reset by touch. Else quite easy for kitten to get fed  twice or not at all with multiple carers. 

Ixp-notes can be used as low cost vibration data loggers for goods in transit. One example is the transit of soft fruit, the ixp-note sensor will indicate via LED and time/date stamped to check when goods damaged. 


 * special plastic mount provides connections to components and allow thin robust paper.


 * The SenseSurface  paper is touch sensitive and can detect taps of varying times, e.g. double click  and also different finger pressures. Gestures strokes on paper can also be detected, e.g. for canceling alarm.  Touch sensitive sensors are achieved by   piezo speaker matrix  inside card  to detect finger  and tap intentions. These piezos also  multiplexed  for audio output and so allow zero additional  cost sensing.  The switch provides tactile feedback, after switch press is recognised the piezo time multiplexes back into audio out mode and gives a vibrate sense to feel.

* Very low cost motion detection is used, this is done using surface mount  optical sensors. These optical sensors are very similar in how insects use sensors to orientate themselves in flight.  This is much cheaper than precision accelerometers. Technology from third parties allows photo sensors to be printed on paper for even lower cost, this is planned for future ixp-notes. 

 * a novel paper loudspeaker allows a loud sound to be created.  A range of synthesised sounds have been tested to  identify objects, e.g. cell phone ring, chimes, bells. Synthesised ringtones  use less memory than sampled sounds and so a smaller package and lower cost.

 * A long battery life is achieved by dynamically varying the computer clock speed, "SmartHeart"  in real time over a range of 1:100 depending on processing requirements.  A slower clock and a nanopower  microcontroller gives a very  long battery life.

A long battery life also achieved in later prototypes,  using SmartHeart,  by using a sensor to directly control clock speed. For example, if card is in the dark, the clock ticks more slowly to save power but speeds up again when in the light. An analogy is the heart rate of a mammal will speed up depending on stimulation, e.g. via eyesight.

 Current card thickness is limited by 3V  lithium coin cell and is approx 1.2mm. The card will switch off when current event has alarmed and switched off  but can be reset to use again. 

* The microcontroller is an 8 pin Microchip PIC , 16F683 as here. It is approx 4 mm square, 3.5kbyte ram, analog inputs, software serial port, built in clocks and uses 2 Volt Nanowatt technology from Microchip.  Also provided 256 bytes of EEPROM for data logging, e.g. temperature every hour for 10 days.

* The prototype  card is 1.2mm  thin but current technology allows a card down to 0.8 mm.

Project status

 July 2009  prototype working microcontroller hardware and software. 

Evaluating manufacturing process for sample cards. 

The team, many thanks to all our contributors for applications, Cambridge and other friends,  and to  current and ex Microsoft  Research colleagues.

 The next version  of Ixp-note will allow the time and date of a future event can also be selected using a PC Calendar e.g. Microsoft Outlook, Apple Ical or Google Calendar. A usb interface allows programming of card. 

Project research and development financed by East of England Development Agency, EEDA.

Previous similar work done by Lyndsay Williams at Microsoft Research : Intelligent Sticky Notes 

 Contact  Lyndsay Williams,  Girton Labs for more information


Early prototype Image by Louise Williams 



Prototype ixp-note with pads for 6 sensors, temperature, light, motion, speaker, mic, touch

Example of ixp-note for reminder. Artwork  by Rick Smith.


Ixp-note in the news