Voltage Regulation
Using the two 7.2 V NiMH battery packs in serial allowed the peak generation of 14.4 volts. Since the batteries voltage will decay over time, voltage regulators are used to create a reliable and stable voltage for the robot.
Different electrical devices on the robot had different requirements for voltage which led to the use of two voltage regulators. A 5 volt regulator (7805) was used to power the arduino, IR sensor, line sensors, and servos. For the larger voltage requirements of the two motors a variable voltage regulator (LM117) was used to regulate the voltage to about 12 volts.
Different electrical devices on the robot had different requirements for voltage which led to the use of two voltage regulators. A 5 volt regulator (7805) was used to power the arduino, IR sensor, line sensors, and servos. For the larger voltage requirements of the two motors a variable voltage regulator (LM117) was used to regulate the voltage to about 12 volts.
In the photo above, the 5V regulator sources the right bus strips of the protoboard. Similarly, the 12V regulator sources the left bus strips. The board was then used directly to power all the electrical devices on the robot.
Due to the relatively large voltage drop across the 5V regulator we did have some thermal issues during the development of the robot. The issues came about when using the servos for an extended period of time (The servos can draw a significant amount of current). The problem was eventually fixed through software which used the servos only when needed. This significantly reduced the time that high current was drawn on the 5V circuit, thereby alleviating the thermal issue.
Due to the relatively large voltage drop across the 5V regulator we did have some thermal issues during the development of the robot. The issues came about when using the servos for an extended period of time (The servos can draw a significant amount of current). The problem was eventually fixed through software which used the servos only when needed. This significantly reduced the time that high current was drawn on the 5V circuit, thereby alleviating the thermal issue.