Team:NAWI Graz/phHardware

pH HARDWARE


[Figure 1 ???]
Fig. 1: The pH-controller for the pH inducible promoter. A 3D printed ground plate was set up with two peristaltic pumps and a H-bridge motor control module. Two lab bottles filled with 1M HCl and 1M NaOH can be placed on the sockets. In combination with the pH-Sensor (DFRobot), it was possible to set the pH value of the reactor medium to specific pH values.
The Arduino code for the pH controller was designed in a two staged mechanism. At first a larger volume of either HCl or NaOH was pumped into the reactor bottle until a treshold value was measured. In this case it was pH = 6.3 for acidic conditions and pH = 7.7 for basic conditions. At this value, the motor control was set to much smaller voltages so the liquid came in dropwise until the desired pH value was achieved (6 or 5).