Embodiments relate generally to electrical and electronic hardware, computer software, wired and wireless network communications, and wearable computing devices in capturing and deriving physiological characteristic data. Techniques associated with an array of electrodes and methods are described, including selecting a subset of electrodes implemented on a wearable device, driving a first signal to a target location using the subset of electrodes, receiving a second signal from the target location, the second signal having a physiological component and a motion component, generating a raw physiological signal using a motion artifact reduction unit, generating a first physiological characteristic data using the raw physiological signal, and deriving a second physiological characteristic using the first physiological characteristic data.
