something like this, its just a 3 wire, 5v, ground, and signal. 5v would work nicely with Arduino and an rc esc bec.
http://www.amazon.com/E-bike-Scooter-sensor-electric-Assist/dp/B00K6YPY1U/ref=sr_1_1?ie=UTF8&qid=1440471477&sr=8-1&keywords=pas+sensor