Geomagnetic storms and sub-storms, sudden commencement, and geomagnetic pulsations are a worldwide disturbance of earth's magnetic field which causes significant damage across the world with a single event. Fluxgate sensor is essential in order to predict such occurrence of the major disturbances. In this study, comparative analysis of Multiple Feedback Band-Pass Filter (MFB-BPF) and Sallen Key Band-Pass Filter (SK-BPF) for the implementation of ferrite based high sensitive Fluxgate Sensor (FS) for earth's magnetic field explorations was carried out using Multisim MATLAB. The harmonics responses of the sensing coil output voltage for the designed fluxgate sensor was tested using the designed second-order MFB-BPF and SK-BPF. The prototype single-axis fluxgate sensor was used to obtain 2nd harmonic magnetic field response with Helmholtz coil. Results show that the 2nd harmonics produced the highest amplitudes of 45.61mV at an excitation current of 18.75mA for MFB-BPF and 51.20mV at excitation current of 50.00mA for the SK-BPF respectively. An indication that the core was strongly saturated at the 2nd harmonics and the MFB-BPF performance proved its superiority over the SK-BPF. The MFB-BPF can be adapted for the development of a high sensitive fluxgate sensor which can be used for earth magnetic field exploration.

The difficulties encountered by visually impaired people has been a major problem in our society. How to carter for their mobility, reduce the danger and difficulties of finding obstacle in their ways and make movement so fast and safer for them. In this study, an electronic walking stick for the blind was implemented using a microcontroller Atmega328 and an ultrasonic sensor. The electronic circuit was simulated in stages using Proteus 8.0 design suit. Stages includes the RF module unit, moisture sensor unit, Light sensor unit, ultrasonic module unit, voltage regulator unit, and the buzzer unit. The simulated circuit was constructed on a printed circuit board and tested for continuity and power ON. Also an evaluation performance test was carried out with 40 volunteers who were blindfolded and walked through a path with the stick for straight obstacles detection, water detection, and the remote control detection. The true positive, false positive, true negative and false negative were recorded. Results shows that the constructed walking stick performed very well according to the specification of the design with sensitivity of 98% and specificity of 96%. Implying that the constructed device can correctly identify 98% presence of obstacles and 96% of No obstacle along the path with 97% accuracy. However, it may also fail to identify 2% presence of obstacles and 4% of obstacles when there are no obstacles. The walking stick with an alarm system is a welcoming solution for the visually impaired people since the device can serve to them like an artificial vision. It is affordable, light weight and suitable for the blind people to aid in their navigation.