1. I have made a processing station out of wood with 5 bottles, 5 servos, and a magnetic mixer. Magnetic mixer works well.
2. Change of plan for the pinch valves. I decided to use fewer and smaller 3D printed parts. Printing big parts is slow, making changes tedious, so I moved to make more use of wood and aluminium. The servos are screwed to a wooden bar. An aluminium bar is fixed beside the servo as "anvil" for the cam to press against. I will probably just use polymorph to hold the silicone hoses in place.
The servo horn has been changed from a helical cam to a straight horn.
3. 3D printed joiners. I only have 1m of 6mm od, 4mm id silicone tube and think I will need about 3-4m. The tubing is fairly expensive to buy in Australia and very slow to bring in from China so I am only going to use silicone tubing in the pinch valve and use clear vinyl tubing elsewhere. This will not affect function. All silicone tubing would be cleaner and more aesthetic. I order to to this I printed 10 joiners to connect the vinyl to silicone.
3. Second air pump did not work. I had ordered a second air pump a while ago from China. Sadly it did not work, (being open circuit) so I did a destructive autopsy. The problem seemed to be the flimsy metal coated plastic brushes. Another one ordered (bit more expensive this time).
4. Servo connector. I made a "dead bug" style servo connector for 8 servos. For the power leads I soldered a thin wire along a row of 9 pins (two rows). For the control leads I joined two rows of 8 pins by thin wire, then glued all 4 rows together with epoxy. I soldered a row of 8 female headers to some rainbow cable for the connector for the Arduino 2560 Mega. This is compact, seems strong and tests out OK with a multimeter.
Test new servo valves.
Test sero connector.