WinkSB said:
Hi there...i need advices on how to construct a pedometer for my project...i have no idea where to begin..kindly advise... :cry:
If this is for school, my first piece of advise is keep it practical.
Commercial pedometers are based on some kind of repetitive movement.
There is some average distance traveled when undergoing this repetitive movement and so you can count the triggers and add up the distance electronically. These of course, would be more accurate the farther one moves. I've seen in these units a small pendulum type device that swings and probably triggers something when a step is taken.
You could do something similar but to avoid the precision mechanics involved in a balanced pendulum, I would suggest using several tilt switches oriented in such a way as the cause successive triggers as a complete step is taken. A digital circuit could monitor the sequence of triggers and "recognize" when a complete step is taken.
Once a complete step can be recognized, it is just a matter of counting the steps and multiplying that by the "average distance traveled per step" to give total distance traversed.
A way to calibrate the thing is to have the user walk a known distance and count your triggers and this tells you how many triggers to expect per unit of distance which can produce the constant described above. The longer the calibrating walk, the more accurate it will be. And for even better accuracy, throw out trigger sequences that did not register as a complete/proper sequence (i.e. some unexpected motion occured so do not count that in the average)
This seems feasible for a small scale project. It could be done with a battery for a power source, a PIC / uC, some tilt switches, a cheap LCD screen for the readouts and prompts, a couple of buttons for inputs to calibrate or count, and some misc circuits for working switches.
Does this at least seed an idea of how to begin?