[mattmarks]

Good morning all - hope thisn't in the wrong thread.

I'm putting an Aim Dash in my spec boxster, but in order to it to register on the dash, AIM tells me that I need to put a "pull up" 2.7k ohm resistor as shown in this diagram below. The explanation per AIM is

Voltage or Resistance

Electrically all sensors can either be resistive (eg a temperature sensor) or voltage (a suspension potentiometer). The problem with fuel tank sender units is that they are normally resistive sensors, and AIM products require voltage signals to work. To convert a resistance sensor to a voltage, a pull up resistor is required, see figure 1 below

V signal = Vref * Rfuel

Rpullup + Rfuel

Equation 1 – voltage divider

This circuit is called a voltage divider, as the supplied voltage (Vref ) is divided between the two resistors (Rfuel – resistance of the fuel tank & Rpullup – resistance of the fixed pullup resistor). Rpullup is a fixed voltage, and Rfuel varies depending of the volume of fuel in the tank. The equation for the voltage output is shown above, in equation 1.

Therefore if two resistors are equal in value, the output voltage would be half the supply voltage. Similarly if the fuel tank resistor is half the value of the pullup, then the output voltage would be two thirds the supply voltage.


So two questions:

1) anyone know where I can get this resistor on a Saturday in NoVa? Amazon delivery is Tuesday.
2) Any additional knowledge on actually doing this?

Thanks!