The Shop > Electronics & IC Programing
capacitive fuel gauge for petrol
Bluechip:
Not having spent much time sussing out this particular application, but there is a bargraph display ic which is essentially just a string of comparators with a variable set point.
LM3914
http://www.ti.com/lit/ds/symlink/lm3914.pdf
Dave
awemawson:
That's the chip I used when I made the fuel gauge for my JCB 803 described here:
https://madmodder.net/index.php/topic,10749.150.html
Still working well :thumbup:
angus:
the display that is used in the kink i originally posted, wont be used.. the dashboard display already runs on 0-5 volt, and will continue to do so.... i will just be using the 0-5v output of the arduino
eskoilola:
Another thing I have some doubts with these sort of applications are high impedances. One MEGA ohm (million ohms) resistance which is supposed to be charging a capacitor. There is also the input impedance of the analog comparator of the microcontroller which being in parallel with the capacitor adds up in a bad way. It does not take much moisture to make this circuit defunkt. Especially in a harsh environment.
An oscillator based circuit is much better as the impedance of it can be made really low - in the milliohm range. From my (foil)hat I draw a figure around 100Mhz. With this one could get very low impedance and convert all nearby radios into whistle boxes. Maybe better in the 16Mhz range. I suppose the counters in microcontrollers can handle that. Using overflow interrupt and another interrupt as reference it should be fairly simple thing to convert the frequency into a figure and go on from there.
Further more I do not understand the need for another IC for the leds. Most microcontrollers have enough IO pins to be able to light the needed leds as wanted.
Noitoen:
After a little digging, I found a dedicated chip for the job. Maybe you cold get a sample :thumbup:http://www.analog.com/en/analog-dialogue/articles/liquid-level-sensing-using-cdcs.html
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