Controlling LED lights by differant ohms reading.

first of all this is my first post so hello. Looking for some insight and help on a custom setup.

I have a project which uses 8 LED lights, each running off different ohms reading.

The lights will indicate a empty and full appearance by color from left to right. My plan is to have all of the lights running when the source reads full ohm range. and turning off as the source gets empty.

As the level drops down, the ohms range will change, in hopes of turning off lights as it decreases.

Think of a fuel tank in a car. Reading 110 ohms at empty and 3 ohms at full, from the sending unit.
when full at 3 ohms i want all of the Leds illuminated, and to turn off as the ohms climb, ending in 110 ohms for the last light.

So here is my question. How would i go about doing this? I am a noob at this and I am having a hard time with an easy way to set this up.

The signal is a 1 wire source and i know i will need resistors, but how do i control when the lights come on and off?

if anyone can help with this it would be appreciated. My project is on hold until i can figure this out.

 

Sorry i had this worded differently for another forum which was no help to me at all


I am deleting the stock fuel gauge from the gauge cluster in my vehicle.

Instead of a new gauge, i would like to make a fuel level meter using a few LED lights in the dash. I would like them to all be lit up when full, and as the tank goes down (lets say 1/8th) i would like a light to turn off, and so on until all lights are off meaning the tank is empty.

The ohms range for the sending unit in my gas tank reads 110 ohms when empty and reads 3 ohms when Full. all other ranges can be determined through math i would assume to find where the intervals are at between the ohm range listed above.

The source is a standard 12V Auto power source.

Hope this made it easier to understand. Thanks for any help guys. I am stumped

 

Interesting, do you know of any meter such as that, in a very small size? i have limited room

 

do you think this would work? it is alot smaller i believe. Also can you clarify on the part of running a curren through the sensor. it already has a signal output.

http://www.canakit.com/2-program-dot-or-bar-10-led-vu-meter-kit-ck134-uk134.html

 

can you explain how i could easily do this?since the sending unit is in the gas tank, can i do this from outside the tank?

 

well the sending unit should already have a source of current from the battery to power it in the first place, correct?

I may be able to just tap into the current thatis already leading to the sender, and use that as the current.

 

disregard that last post. i found some really good info and i think i understand now.

my last question is about this LM3914

is this a full build board with LED's on it that i can do this with? or is the LM3914 just a chip and i have to build a board using it?

if it is a full unit, do you know where i can purchase one.

 

ok so i ordered up a kit and have everything to make this work, the only thing i cannot figure out is determining the resistor size to get it to read my range of 103 ohms to 3 ohms? any thoughts

 

sorry i was out of town and i appreciate all of your help with this. it is not really my area of expertise. so it is running a 12v system and should be 102-118 ohms when empty and 1-5 ohms when full. These are the ranges from the manufacturer, so safe to say 3 at empty and 103 at full.