Within the first two weeks, we managed to finalise our project idea, as well as how we planned to execute it. After our progress check meeting and an additional meeting with Hanyang, we settled on constructing a serial dilution machine. For this, our team managed to come up with two possible plans. 

Firstly, we thought of employing a micropipetting system mounted to a robotic arm, that would be programmed to move between beakers to carry out serial dilution. The arm would be programmed to move along the x, y  and z axes, to move between beakers, draw liquid, and eject used pipette tips into a waste bin. To mix the solutions, we thought about programming the pipette to pipette the solution up and down to thoroughly mix the solutions in each boiling tube. We also thought about using a magnetic stirring system for mixing. 

Secondly, we were thinking of using chambers attached to peristaltic pumps. The pumps would be controlled to pump a certain amount of liquid per unit time, allowing us to control the volume dispensed by controlling the run time of the pump. The liquid would then be dispensed out into another chamber, with a small portion of the liquid being channelled back into the same chamber for re-dilution. 

We decided to go with the micro-pipetting system with magnetic stirrers for a few reasons: accuracy, ease of cleaning, efficiency, and reliability. Overall, a micropipette would be far more accurate than a peristaltic pump in dispensing a specific volume of liquid. Improving accuracy in volume dispensed by a peristaltic pump would mean having to pump out a smaller volume per unit time, which would compromise efficiency. 

Moreover, cleaning involved in the micro pipetting system would be limited to throwing away and replacing ejected tips, as well as rinsing off the beakers and magnetic stirrers. Cleaning in the pump system would be far more difficult due to the use of narrow tubings, and would possibly need us to dismantle the whole closed chamber system to rinse out. 

Additionally, using the magnetic stirring system would be far more efficient and reliable than pipetting up and down. The magnetic stirrers would be stirring consistently and concurrently with dilution, unlike for pipetting up and down, which would require less time. It would also avoid having to programme additional pressing commands of the pipette to suck the liquid up and down, hence reducing the risk of mechanical failure. During this time period, we also attended the 3D printing lessons, hence familiarising ourselves with 3D modelling on Fusion360 and operating the 3D printers.