Using arduino and NTC as a fuel reserve sensor

Hi!

I'm planing to build fuel reserve sensor for my bike with arduino and ntc.

I've found this simple schematic with PIC micro controller: http://dl.dropbox.com/u/15796853/0.GIF

This sensor above works on principle that PIC turn ON/OFF NTC every 30 sec, and checks variations in temperature. So if temp. is rising high, that means that there is no fuel to coll the NTC. And if temperature isn't rising that means that there is fuel in tank which coll down the NTC.

I know how to write code which will turn on/off NTC and I know how to read temp, but what do you think how should interval between two checks be long, and how many difference in % should be between old, and new temp after that interval.

NTC is 100 ohm.

Thanks!

it will depend a bit on the mechanical volume of the NTC. but I would say Test, test, and test again. I can not access the link you gave , no rights to view attachement

I edited the link!

You're planning to put an electrical heater inside a fuel tank - are you certain that's safe?

PeterH: You're planning to put an electrical heater inside a fuel tank - are you certain that's safe?

Jep, this is 100% safe, on similar principle work's this kind of sensor on most bikes which doesn't have the float, but this my way is much more safer because I'm planing to turn off ntc after some time, maybe 20 secs to let it cool.

On other bikes you have the lamp conected in series with the ntc, 12 v and GND, and when there is no fuel in the reservoir to coll the resistor it heats up and it's resistance goes down, and then lamp starts to shine.