How to interface an arduino to load sensor with darlington transistor? I have a load sensor for measuring weights , it has for wires labelled E+,E-,S+,S-. I assume S means sensor and E means excitation and the power is sent into E+ and E-. 
The output of any load sensor would be the order of typically millivolts if it takes a load (depending on the weight of the load of course) so I guess amplifying it with a darlington would make its output useful for an interface to an arduino.
What would be a generic circuit using a darlington transistor (e.g. a TIP 120) that can make the load sensor output useful for building an interface to an arduino with the minimal number of components? Ans this circuit is to be as simple as possible. 
Im trying to build a circuit with the components I have which does include a tip 120 and I have a lot of other common components.
What you have there is (or sounds like) a full wheatstone bridge.

You require either a special amplifier (such as the HX711) or a highly sensitive and accurate differential ADC (such as the MCP3428 - (on  a shield)).