processing and controlling the collision warning. The 40 kHz ultrasonic ceramic transducer consists of a transmitter and a receiver, which are used to detect obstacles in front of the user. A Tactile feedback with a 3-volt 80 mA 12,500 RPM vibration motor is used to generate the warning signal. An electronic magnetic speaker informs the device status and battery information to the visually impaired with a beep. An In Circuit Serial Programming
(ICSP) port is a serial interface used by the microcontroller to download a program into the microcontroller’s program memory. Users can charge the device using a 3.7-volt 1,150 mAh rechargeable Li-PO battery with a 5-volt DC switching adaptor via a DC-Plug charger
at the bottom of the device. The power consumption by the device is about 75 mW when used with a Li-PO battery 1,150 mAh at 3.7 volts. Average battery life is over 24 h of continuous use, and 48 h of standby. The dimensions of the device are 504025 mm with a weight of 65 g. Our device can be mounted at the user’s chest level with a neck strap, as shown in Figure 4 (right).