Our son worried us a bit a couple of weeks ago when he had quite a nasty fit, so I have been thinking about making an alarm to warn a carer that a person in their charge is having a seizure.
There are a few different ways to do this that I have thought of:
- Detect Movement using an accelerometer
- Detect the sounds associated with the movement using a microphone
- Monitor the movement with a CCTV camera and use image processing to detect the abnormal movement.
- We do not want false alarms caused by normal movement – I am addressing this by using a fourier transform to filter out only a range of frequencies of movement, in the hope that I can select the characteristic shaking of a seizure, but not detect too much normal movement.
- A quick shake should not raise an alarm, so to set off an alarm the acceleration in the appropriate frequency band should be more than a threshold value for a specified length of time (3 sec currently). This will give a warning ‘pip’. If the shaking continues for 10 sec, it raises a buzzing alarm.
- Sensitivity will be a problem for detecting it through the floor – will need to work on that another evening.
The completed prototype is shown below: