Next hurdle - The sensor

I'm happy with the visualisation i have now (will upload an example soon) and now its time to fully tackle the sensor connectivity problem.

The first stage, which i've already overcome, regarded the way i can use the sensor and manipulate it without destroying a £300 piece of hardware. After a little digging around i found the type of connector the nexus used for its auxiliary input, a LEMO 0B 5-pin. I found the tech sheets on it and after A LOT of looking around found a company which makes a female equivalent.

Next few problems -

Firstly the female connector needs extending so that i can work with the signals and power it correctly. At the moment the adaptor is extremely narrow. This maybe solvable using some jumper wires and some very delicate soldering.

Secondly the sensor needs powering. For the nexus tech sheets it shows that the auxiliary input to the amplification pack (power etc) provides +5, -5v, and 0v to the sensor. I am presuming here that the sensors require powering and that they are not passive. The BVP sensor (heart-rate monitor) works with Infrared so i guess they need powering. The issue is of course how much current to provide it with. From the tech sheets this suggests 10mA - clearly i don't want to damage the components. I need then to be able to provide a stable power supply. The Arduino only provides 5v and 0v so this means i may have to use an inverting unity gain amplifier to change the polarity of the signal. After this i should be able to pull the current levels down fairly easily if too high.

The third issue of course concerns the way we are able to detect if the sensor is actually doing anything. I have a digital multimeter but this will not be precise enough to figure out exactly what is going on. The final two pins of the LEMO connector provide a positive and negative signal return. Do i need to use both these? Does the base unit augment the signal using a difference amplifier using -sig and +sig as inputs? this would make sense however its a presumption.

Essentially i need an oscilloscope, a bit of solder, a couple of simple op amps for the power supply, and some patience.