This paper reports the design, fabrication and characterization of a head-mounted, flexible, and ultralight optogenetic system that enables wireless delivery of light into the brains of awake and freely behaving animals. The project is focused on miniaturized design, light weight (2.7g), small volume, low cost (<; 25 USD) and simple fabrication. The chip, the substrate material, the battery, and the micro light emitting diode (μLED) are commercially available. The device implementation consists of one step photolithography, soldering, and packaging along with Arduino programming. In vivo study is carried out where the battery-powered μLED stimulates the visual cortex of a rat with parameters that can be controlled wirelessly via a smart-phone user interface application. The efficacy of optical stimulation is validated using c-Fos as a report of light-evoked neuronal activity.