Hi all.
I do have a some sort of plant that have fuel level sensor, 0-90ohm paired with gauge.
I'm thinking of using a digital device to monitor fuel level, however if I measure the sensor pins across I only get something like 1.02v which at 75% fuel level. I do t think this is right.
I goes I have to pull the signal wire either to ground or 24v so my question is:
What resistor value to use?
Pull it to ground or 24v
What to do, so the gauge still operates as before? Diode?
The gauge rely on a current I believe so pulling the signal wire may have some effect on the cab reading.
That kind of sensor changes value from about 90 ohms FULL to about 10 ohms EMPTY.
Easiest way is to use it in a resistive voltage divider.
150 ohm resistor from Arduino 5V to sensor lead
USUALLY the sensor has one side grounded to the fuel tank. Connect Arduino and Fuel tank grounds.
So what you get: 2 resistors in series. 90+150=240 the 5V is divided across them, so 90/240 = .375 which is the RATIO of the divider. With 5V across the series resistors, the sensor connection is connected to an Arduino Analog input. With the sensor at 90 ohms (full) the Arduino will read 5.0V * (90/240) or about 1.875 volts. You need to scale that to some variable like 0..100 percent full, in Arduino code.
MANY of the older cars use that 90 ohms type fuel tank sensor. GOOGLE THAT
Hi Terry
The thing is that the device I'm connecting to 8s not arduino but a tektronica tracker. The tracker accept 0-30v on the analogy input. Device and sensors share the same ground. 24v supply (28vv
When engine running)
So, should I pull that signal wire with 150ohm? Is the gauge on the dash be affected?
Thanks
So, should I pull that signal wire with 150ohm? Is the gauge on the dash be affected?
The gauge on the dash is reacting to the resistance charges of the sensor.
You can expect it is putting some amount of current through the sensor.
Can you read the VOLTAGE from ground to the sensor? You should be able to send that to your tracker.
How that voltage SCALES to the 30V input is the question...
How accurate do you need the reading to be? You MIGHT have to amplify the sensor voltage with an operational amplifier IF you need very high resolution readings. If "1/8 of a tank is good enough" maybe no problem..
Read that voltage and let us know..
you are asking in Arduino forum...?
Most of us are here trying to solve a variety of problems.
terryking228:
The gauge on the dash is reacting to the resistance charges of the sensor.
You can expect it is putting some amount of current through the sensor.
Can you read the VOLTAGE from ground to the sensor? You should be able to send that to your tracker.
How that voltage SCALES to the 30V input is the question...
How accurate do you need the reading to be? You MIGHT have to amplify the sensor voltage with an operational amplifier IF you need very high resolution readings. If "1/8 of a tank is good enough" maybe no problem..
Read that voltage and let us know..
So i did measure the sensor signal wire btw ground. It was 1.02v same as btw the sensor terminals. 1/8 or even 1/4 be good enough