Hi all, im new in the circuit design area but always willing to learn. I am building a project R/C car (nitro powered) and want to create a low fuel indicator. I had a look at another post on the forum and saw this circuit - http://www.electro-tech-online.com/viewtopic.php?t=60 .

I would like to build a kit like this but could someone help me with changing the design so a light (instead of a buzzer) turns ON when level is LOW.

thanks in advance.

Dave

 

That design relies on the conductivity of water to trigger it. I don't think that RC fuel is nearly as conductive, so you would need a float switch of some sort. You just need to configure the switch such that it turns on when the level is low, and insert it where the contacts are shown in the schematic.

Replace the speaker and C2, with a resistor and LED (in series), and you will have a flashing low fuel light Oh, and you will have to increase C1 to about 10uF, to slow the oscillation down to a visible rate.

 

A guy i spoke to that fly's RC helicopters has built one except it has a scale of LED's showing the fuel level and he uses copper rods as a conductor. so the fuel is conductive. He sells this kit but its too extreme for my needs thats why i would like a small and simple unit like this.

whether i does or doesnt work, i still want to try it so could someone help me with altering the unit so the LED does turn on when level is low?

Thanks

Dave