Ultra compact scan systems which may be held in the manner of a pen or wand during use and ring mountable scanners suitable for wearing on one's finger, wrist or another part of the body are disclosed. Embodiments of wearable scan systems are disclosed which need not contain traditional light collection apparatus. Highly ergonomic non-mechanical actuation methods are described which eliminate the operation fatigue characteristic of prior art devices that use mechanical levers to turn them on. Novel axial scan elements for the scanners are adapted to operate in a pulsed mode to minimize current consumption. Various scan head embodiments are operated with simple, low cost, low parts count, one-shot circuits to provide low bulk and long battery life even when small button cells are used to power them.