augustin87r
New Member
Hello,
I have a BMW F650 that doesn't have any indication about the fuel level, not even a reserve warning light. A reserve light is very useful , you never know when you run out and have to switch to reserve while riding, which is not very comfortable nor safe...
So, Africa Twin uses a NTC thermistor to light a bulb (look at the first attachment). When a current flows through a thermistor, it will generate heat which will raise its temperature above that of its environment; so, when they are submerged into a fluid (gasoline in our case) they are getting cooled, maintaining high resistance; when the level of the gasoline is getting lower and the thermistor is not immersed into the gasoline, their temperature is getting higher, roughly decreasing their resistance.
Because the bulb lights with 'fading' effect somebody made a schematic with 2 comparators. I don't need the relay, because i'm not going to use a bulb. It's too big for my dashboard. I'm going to use a LED in the collector of the transistor.
Questions:
1.Pls look at the second attachment. Do you think is it going to work?
2. Is it OK if i replace the bulb with a resistor of a few ohms 1 or 2 W? What value shoulf the resistor have?
The article that i read :
**broken link removed**
I have a BMW F650 that doesn't have any indication about the fuel level, not even a reserve warning light. A reserve light is very useful , you never know when you run out and have to switch to reserve while riding, which is not very comfortable nor safe...
So, Africa Twin uses a NTC thermistor to light a bulb (look at the first attachment). When a current flows through a thermistor, it will generate heat which will raise its temperature above that of its environment; so, when they are submerged into a fluid (gasoline in our case) they are getting cooled, maintaining high resistance; when the level of the gasoline is getting lower and the thermistor is not immersed into the gasoline, their temperature is getting higher, roughly decreasing their resistance.
Because the bulb lights with 'fading' effect somebody made a schematic with 2 comparators. I don't need the relay, because i'm not going to use a bulb. It's too big for my dashboard. I'm going to use a LED in the collector of the transistor.
Questions:
1.Pls look at the second attachment. Do you think is it going to work?
2. Is it OK if i replace the bulb with a resistor of a few ohms 1 or 2 W? What value shoulf the resistor have?
The article that i read :
**broken link removed**