[Gumstix-users] building a bike rpm sensor and connecting it to gumstix

[Andy T. <tri...@gm...>]

Hi, I'd like to build a sensor that readHi, I'd like to build a senso
Hi, I'd like to build a sensor that reads the rpm's of my bike 
and connect that to the gumstix. I was thinking of using 
something like a hall effect sensor, or maybe something 
optical that would sense everytime an led came around on 
the spoke.  I've read about the robostix, the GPIO on the 
gumstix, but I'm not really sure what the best way to do 
this would be.  I've seen lots of sensors that you can buy 
that  give you this on a display, but I'd like to interface 
it with the gumstix (it's for a senior design project where 
we are recording the heart rate  along with rpm of 
someone bicyling and storing it a database on the gumstix).

Has anyone had any experience building a sensor like this? 
Or some general guidelines on how to access data from 
the input lines.  I read somewhere on this list you would be 
able to access it from linux just like 'cat proc/ADDR01', 
is this available now or is it harder?