Devices, methods and systems described herein provide for removably attaching an electronic device holder to a set of headrest bars of a seat in a vehicle in a manner which allows the user, while seated in the backseat of the vehicle, to utilize the electronic device without holding the electronic device. The branch locking may be accomplished by one of several methods. An imaging pixel having a photodiode is formed within the semiconductor layer, where the photodiode is an N- region formed within the P-type region of the semiconductor layer between the frontside P+ doped layer and the backside P+ doped layer. The integrated circuit can be part of an FPGA or FPGA fabric. Alternatively, the power unit includes a converter to boost the external power source voltage and to charge the battery when using the battery with a voltage lower than the external power source voltage.