Electrical stimulation has long been used in medicine to induce phosphenes, or visual sensations, in patients with visual impairments. Recent technological advancements have made this stimulation more accessible to the public, inciting a new era of research on neurostimulation for sensory enhancement. Transcranial Alternating Current Stimulation (tACS) can non-invasively induce visual sensations called phosphenes (bright flashes) in the visual field with cutaneous retinal activation. We explore the use of tACS to elicit visual sensations and explore potential use cases. We designed a wearable tACS system and conducted a study to understand the visual sensations we could elicit and their efficacy when applied to augmenting a users spatial awareness. We found that our device reliably generated synthetic sensations and, when applied, significantly augmented users' ability to "see" objects approaching from behind compared to users with no feedback. We hope to inspire future research using tACS in systems for sensory enhancement.