This paper proposes the design and implementation of the functional electrical stimulator using the ultra low power microcontroller MSP430 , which restores the functionality of paralyzed portion of human body due to spinal cord injury (SCI) that consumes the power supply generated by the body. FES stimulates muscles enough to make them contract. FES strengthens muscles, relaxes then and improves their function. This system removes the drawback of suppressing skin breakdown and itching and reduces power consumption. This device uses fully programmable symmetric biphasic pulses with inter-pulse interval for surface electrodes and it works in both modes: open loop as well as closed loop. A MSP430 microcontroller which operates at low power consumption is used for control of stimulation parameters such as stimulation frequency, pulse width, inter-pulse duration and pulse amplitude, provides higher currents used for gait analysis. EMG signals are recorded by sensors for closed loop operation and in open loop it operates by use of push buttons and LCD display. The power supply generated by the use of thermocouples that produces power supply from the body heat generation.