Hi Guys
I hope you can help me.
First of all, I´m not an electrical engineer, so I probably don’t understand short terms, and very complicated words etc.
I´m doing a project, where I want to rebuild an insole as a pressure pad – no problem here so far. Then I want to record or even better send the duration of the signal (from the pressure pad, when it´s activated) directly to Matlab for analysis through wifi. I don´t know which components I should use for recording the signal and transmitting it to Matlab. Do you have any suggestions?
It´s crucial that the detection of the signal is very fast so I perhaps can measure a difference in the ground contact time with each step. (For an example, a patient with a new hip alloplastic would have a shorter contact time with the ground on the newly operated leg due to pain.)
An Arduino can easily measure times with millisecond resolution (1/1000 second).
You can also measure times with microsecond resolution if you have a millisecond or so breathing room between inputs to do your data analysis and store or send the data.
The clock isn't perfectly precise though. Measurements may be inaccurate by +/-1 microsecond.
I can't see more than 10 footfalls happening in a second, so the Arduino is plenty fast enough if you can live with the resolution and accuracy limitations.
Will the footfall sensor be in a shoe? Gonna need to strap the Arduino, battery, and Wifi module to the patient's calf and run wires down to the insole. Should be do-able though.
The most recent sketch (at present) can detect a 5 µS interval. Unless your patient's foot is touching the ground over 200,000 times a second that should be adequate.
