Hi,
How could I connect this oldschool fuel tank sensor(as seen on picture) to arduino?
http://goo.gl/sJTNFw
I understand how to connect a potentiometer to arduino, but how to connect this one wire sender? They should be basicly same things?
Thanks,
VFTS:
Hi,
How could I connect this oldschool fuel tank sensor(as seen on picture) to arduino?
http://goo.gl/sJTNFw
I understand how to connect a potentiometer to arduino, but how to connect this one wire sender? They should be basicly same things?Thanks,
Sort of. What that sender is acting like is one leg of a two resistor voltage divider. That single terminal needs to wire to an appropriate sized resistor that is then wired to a fixed voltage, either battery voltage or possible from a voltage regulator. The sender will change the resistance inside the sender proportional to the gas level and the junction of the sender and fixed resistor will be a variable DC voltage proportional to the fuel level.
Start by measuring the resistance of the sender between the terminal and it's mounting bracket while you move the float through it's range. Once you know it's resistance range you can work out a good fixed resistance to use.
Lefty
I agree with Lefty, but to clarify, the sender is really a "two wire sensor". One of the wires is the mounting bracket or sensor body, which in normal operation must be connected to the vehicle ground.
Be VERY careful.
Spark + Gasoline Vapor = Bad Day
Hah..... my '62 was definitely one wire- a Bowden cable arrangement in fact. Wasn't even electrical- the float levered the inner cable which then levered the needle on the gauge.
New fangled electrical nonsense.
As I am sure you know, that VW did not have a gas gauge. Instead it had a valve on the floor near the gas peddle to allow access to the "reserve" gas.
Another potential problem is the fact that this year VW has/had a 6 volt system. This could be a problem in that usually the supply voltage needs to be 1.2 volts or more above the regulated output. If you are regulating to 5V they you need a little over 6V input. With the generator running that will be the case but maybe not with the engine off. On the plus side, the arduino/atmega328 works fine on less than 5 volts.
One option is to upgrade to an 8V system. An 8V battery is a little harder to find, the regulation needs to be replaced or adjusted. The upside is that nothing else needs to be replaced, the starter spins a little faster and the wipers work a little better.
Good Luck.
that VW did not have a gas gauge
What VW didn't have a gauge? The OP doesn't mention a year. My'62 already had a gauge, not the reserve valve thing.
The sender in his pic is from '68 on- by then they were 12v.
Interestingly, the OP doesn't actually mention that the project s/he's talking about, is actually to be used in a car at all.
My memory is not as good as it once was but I thought that the gas gauge was introduce in 63 or maybe 64.
68 was a good year but the 67 was better. 67 was the first year for 12V and the last year for the old body style.
I think I would measure the resistance range of the sender and see if I could use it in a simple voltage divider that I could safely read with one of the analog inputs.
Keep us posted. 
I thought that the gas gauge was introduce in 63 or maybe 64.
No my '62 had one, but it wasn't electrical, it was a Bowden cable.