Night Time Alert

Project  / Project number: P1248  /  Status:

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The challenge

A solution was required for use by a mobility impaired client who requires assistance through the night, and therefore needs to frequently wake up their deaf spouse in the night for assistance; the Client also had difficulty speaking.  The previous method of doing this was to use a stick to prod their spouse through the night, this method was far from ideal; therefore the Client’s family came to Remap to develop a better solution.

The Client had the following requirements:

  • The Client had mobility problems and reduced strength, therefore the trigger for the alarm needed to accommodate this.  A button and pull cord was ruled out following assessment by the Occupational Therapist.
  • The Client’s spouse was deaf, so the alarm could not be audible.
  • The Client’s spouse was also a heavy sleeper, and lights were generally kept on in the hallway, therefore a visual (flashing) alarm was ruled out.
  • The solution should avoid the use of batteries to avoid having to remember charging things.

The solution

An electronic Arduino based alarm unit was developed.

The Trigger:

Following assessment by the OT, we came to the conclusion that a wobble switch was most suitable method of setting off the alarm.  Off the shelf wobble switches are quite expensive, therefore a wobble switch was built for a fraction of the cost using a modified joystick potentiometer (with a foam finger) and an Arduino Micro that monitored the output of the potentiometer to detect movement.  A limit was set in the Arduino software to avoid erroneous or accidental triggering.  Two Neopixels were used to lightly illuminate the wobble switch actuator  and provide visual feedback to the Client that the alarm had been set off.  The wobble switch was mounted to an adjustable camera mount that clamped onto a grab rail by the side of the bed, and positioned such that it could easily be activated with the Client’s hand.

The Alarm:

The alarm used an off the shelf pillow vibrator that is used for alarm clocks for the deaf / hard of hearing.  A 12V output was controlled by the Arduino when the alarm was set off.  A PWM signal was used to control the intensity of the alarm that could be configured so that it didn’t startle the Client’s spouse, or cause discomfort when the alarm was triggered.

The Overall Unit:

The alarm had the following features:

  • Wobble switch triggered alarm
  • Pillow vibrator alarm
  • Adjustable vibration levels
  • Two stage alarm, first trigger sets off alarm which gradually increases in intensity over time, second trigger sets vibration to maximum with more intense pattern.
  • Mute and reset function.
  • Test function.
  • Visual indication of status and alarm activation.

Videos of product development and prototyping are linked below:

https://www.youtube.com/watch?v=EcXczA3Myns

https://www.youtube.com/watch?v=LkCtfy1guJk

https://www.youtube.com/watch?v=BrTUl1IpIuo

https://www.youtube.com/watch?v=dCPPFtGZp1o

Current Status:

The unit was in use for a number of months and functioned as required, but developed issues with cable fatigue during use and taken away for repair, during which time other faults developed.  It was taking too much time to repair and was eventually replaced with a similar, but smaller Bluetooth device that had already been prototyped by another member of the panel.  I would like to try and develop a robust and standard Arduino based alarm system platform off the back of this for use in similar projects, addressing the shortcomings of this solution;  any assistance would be appreciated – in particular fabrication of custom Arduino Shields and circuit boards.

The benefit

The Client was able to easily call for assistance through the night, providing better peace of mind for both the Client and their spouse.

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