The electrical engineering concepts evidenced in this project become apparent in the design of the system's feedback loop. A feedback loop is necessary in order to insure that the required voltage is maintained across the anode and cathode of the wet battery. This can be done a number of ways. However, because there will be software analysis involved in controlling the state of the system, it appears to be most effecient to merely send the current potential state of the anode/cathode pair to the Logo input board. This can be done effectively by creating a new input icon for the Logo software controller which will read the desired voltage range of the battery.
However, this may not be possible with the Logo package. In this case the student will have to trick the Logo board into thinking that it is a different input device. This may be accomplished by using the temperature input device as a model. The yellow inputs on the Logo board, such as the temperature sensor have input ranges from about 2 to 4 volts (approximately). This is ideal since the voltages that we will be dealing with will be about 2 volts. If the input voltage however is a problem (whether it be too high or too small), then the voltage can be easily scaled through either an simple op-amp circuit or a voltage divider as shown below (for the voltage divider, Vout=Vin*[Rb/(Ra+Rb))].
Thus, this project has great potential (pardon the pun) to to introduce several exciting concepts of electrical engineering to the students. Also, since we are designing with a battery there is also the opportunity to add more eleconic features (such as digital displays etc) if time and current permits.