I implemented the pid control system and connected the electronics for braking, however the braking process appears to inject too much high frequency noise to allow the RPM to be reliably detected with good accuracy using this approach. Detecting current rather than voltage might work better, I ordered some sense resistors to try that approach. I can also use the ADC of the pico instead, and possibly use the extra core of the pico to improve timing issues. However it is starting to look like an external encoder is a better idea than trying to use back emf. Indeed perhaps I should give up on back emf now. The motor controller is able to detect the rpm and position of the motor using back emf, but they use a processor running C or assembly, c is about 100x faster than micropython, assembly faster still. It may not be viable in micropython. Took a video to show the operation of the braking electronics/proposed system and that it is viable.

rigged the half h=bridge L298N modules to perform passive braking from the PWM of the Pico, and set aside for later, for use in combination with an rpm measuring system, this is large enough and powerful enough that we can use it for the main centrifuge hopefully. We can use the actual hardware I have prepared, not just the design, I will just keep it assembled until we need it.
rigged a test brushless motor to a fan, connected a phase to a rectifier bridge, divided the voltage down to protect the pico verified with the oscilloscope, trie dto measure the frequency with the pwm in peripheral on the pico. Noise is a major problem, tried a couple RC filter,s found one that seems to work, but for some reason the PWM counter is still giving the wrong frequency, I can confirm it on the oscilloscope. The next stage will be to try using the ADC and high frequency polling to try to track RPM. If that is not reliable, we must cook up some kind of encoder with the photointerrupter or buy an encoder, encoders are totally overpriced for some reason so we might as well just cook up our own in a minute.

Made a pico program to control a fan with a pid loop, using the pwm peripheral to measure fan speed, as interrupts were not accurate enough. the fan speed measurement still isn't very accurate, something is wrong. It varies by more than 10% even when I measured the signal from the fan on my oscilloscope and that's not the problem, it is the pico. I can try using the pio peripheral next, and posting on forums. If it can't be solved we can't use the pico, and will have to try using an arduino or something instead, like the teensy.

advanced the cad further earlier today, added the other motor and motor mount, decided on and implemented a strategy for the rotating seal and upper drive, modified and improved things, dealt with some errors and issues with fusion.

Further investigated pico, got interrupts working, got the fan tach signal working, we could use interrupts, will investigate pio later.

Investigated the use of the raspberry pi pico for use as a master controller of the centrifuge, controlling the peristaltic pump, acceleration, test run time, and rpm and relative rpm of the screw and barrel. Some technical difficulties, wrote a program to try to use interrupts to track the FG (frequency generator) output of some fans, the motor controllers for the spindle motors has a similar output to track rpm. It does not look viable. The next thing is to explore the use of the pio peripheral to monitor RPM.

Added motor mount and motor coupler, solids collection geometry, adjusted width of tube etc., got everything in place, error free etc.

Made some decisions on how to do things, advanced the cad, also did some research on how to do the firmware for a pico that controls both motors and a peristaltic pump

Made some decisions, did some cad, shopping/sourcing parts, plans for the show at the maker festival

shopping, considering options, some CAD, for centrifuge drive systems.

Did more cad on the centrifuge, it is mostly done now I think, it could still be split for printing or whatever.

Started work on the centrifuge. Make the screw and barrel and cap, sourced o-ring that fits and bearings. We still have to decide on a drive mechanism and I would prefer to do this before doing much more CAD as it has implications and changes can be hard to make.

Did some planning and figuring with Tibi at the weekly meeting, made a plan for the CAD work to be done on the next version of the decanter centrifuge. Tibi will do the small scale test to ascertain the potential processing rate of the centrifuge. We also discussed the intriguing possibility to manufacture the parts with SLS in metal, as Wikifactory people tell us they can get a good deal on it.

Discussed and made some conclusions on the design of the decanter centrifuge, considered self balancing mechanisms, what the barriers are and how to solve them. Decided on a plan of action: build a regular "mushroom hat" centrifuge to test the settling rate characteristics of the protein coagulate first, then if the results are promising, probably do a revision 2.0 of the main decanter centrifuge, to employ 2 metal shafts, eliminate the big bearing, keep the bearings away from the fluid, and employ direct drive (possibly, maybe not, there are issues with torque vs. speed curve matching that may require us to use pulleys. We may replace the pulleys with non-toothed pulleys or larger pulleys for better wear resistance.)

research on options for rotating seals for centrifuge, considering options for moving the physical prototyping forwards

Travelled to Montreal to deliver parts, finish parts, assemble and test centrifuge, and document it all, at the Sensorica Lab. Mission accomplished, mostly. Many changes are needed, and the manufacturing limitations are serious. also see $50 for gas and 2 hours travel time, logged elsewhere.

improve cad file with modifications to the screw, schedule progress for milestone 1, expand bom.

printing, post processing. removing support from the internal rotor is a real problem. soluble support material and dual extruders is valuable, clearly.

Improving CAD, printing.

Inspect cad model, make final improvements, export and start the prints. filament cost will be logged elsewhere.

Replaced the bearing with a bigger one, shopped for the bearing, adjusted the model to accommodate everything, double checked everything to be sure it is all ready for printing. Still need to add holes to mount that uppermost bearing plate.

improve cad model, make some design changes, shop for parts.

I did some more on the fusion cad file for the centrifuge, design and drawing.The motors still need a few more dimensions. Redrew the motors, and added and adjusted everything for the mounts that come with the motors, decided on strategy to mount the motors after considering several options, they need to be changed so the fan does not stick into the bucket.

designed and added added motor mounts, teeth to pulleys,modelled motors and checked over the cad file

Tibi and I determined some of the details for changes/updates to the CAD model for the centrifuge, which I will make later.

Accumulated over a few days, thinking with and work providing to Anthony, who produced the CAD files.
Drove the documentation of this prototype
https://docs.google.com/document/d/1Eq32CS5Lr5qy8SvmcNOLg8heyqcrqfEfMRUhx3XsUl4/edit

implemented the planned changes:
improve seal around cap and outer rotor, I added a groove for the oring to stick to, but realized a better idea is to increase the number of bolts. It is quite a lot of bolts, but will reduce the chance of leakage issues/the need to reprint a different one. There is no ridge in the cap itsself as it appeared it would be unhelpful anyway.
-thicken cap
-check over it all for errors
-put the hole back in the inner rotor
-thicken the shaft walls. There is a limit to this. I thickened both shafts, and reduced the central hole diameter.

- I was not able to make any progress with the pulley/shaft interface. There just isn't really enough plastic there to do much and still have enough strength. I could put some very thin threads on perhaps that would be ok, yeah.

Modified Extruder Pro from Precious Plastic to match the needs for Green for Good. Design modifications were done to the extrusion screw to match the required processes. A bit of work is needed to finalize the leaves crushing section. The design modifications were made to the shared OnShape model.

https://cad.onshape.com/documents/e5ffe24c901e0463cea1c3a5/w/894b77f33ef5631b42db8302/e/c285d73b693d1bab88f0a39a

Set up the working, design and prototyping documents.

Cleaned up Deliverables doc. Extracted some content and put it into presentations. Better flow, easier to read.
https://docs.google.com/document/d/1g6DbV0mSqwU6rdLqyrv5Ctw_3cHamuPZLFXwajPkN4g/edit#

Worked on Design Considerations, documented some ideas in the table, told that to Tibi.

Visited a local corn miller in Njombe and added info and pics to general considerations: https://docs.google.com/document/d/1g6DbV0mSqwU6rdLqyrv5Ctw_3cHamuPZLFXwajPkN4g/edit#

Searched and documented different techniques to manufacture screws for extruders.

Spent time with Tibi discussing General Design Considerations, talking notes in the cod / table.
Introduced the village corn mill model.

Spent time with Unai discussing General Design Considerations, talking notes in the cod / table.

Discussed a visual of the design architecture of an extruder with Bernard. He had already made a first draft, we discussed fine-tuning it.

Discussed a visual of the design architecture of an extruder with Tibi. I had already made a first draft, we discussed fine-tuning it.

Finished the Build Understanding presentation and presented at the Build Understanding meeting.

Helped Tibi with the Building Understanding presentation: feedback and formatting.
https://docs.google.com/presentation/d/1WpRGuaFrFYwCeyw-kRZSqxvARfo0OIhqLxjk1Ov_vO0/edit#slide=id.p

Worked on the Building Understanding presentation. Mayssam helped a bit
https://docs.google.com/presentation/d/1WpRGuaFrFYwCeyw-kRZSqxvARfo0OIhqLxjk1Ov_vO0/edit#slide=id.p

Worked on the Building Understanding presentation. My point of view
https://docs.google.com/presentation/d/1WpRGuaFrFYwCeyw-kRZSqxvARfo0OIhqLxjk1Ov_vO0/edit#slide=id.p

Searched info about protein processing and surveyed companies that are engaged in this field.

Processed Bruce's mined info from his doc, into the Deliverables work, structured information.

Information mining, delineating conceptual space, pile data in this doc.
https://docs.google.com/document/d/1qt48RPToG9qfQssWqH4qMcs3rPJkMqC2ZlP_K8l3ts0/edit#

Added a few organisations and documents to Diigo
Met a local artisan in Njombe (Tanzania) who can provide design considerations.

Explored concepts for shredding and squeezing leaves. Captured some examples of devices that instantiate these concepts in the Deliverables doc. Shared ideas with Tibi.

Had a meeting with Tibi to order parts and plan for the prototyping of the second version of the decanter centrifuge.
Made a BOM on the doc
https://docs.google.com/document/d/1Eq32CS5Lr5qy8SvmcNOLg8heyqcrqfEfMRUhx3XsUl4/edit#

Had a meeting with Anthony to order parts and plan for the prototyping of the second version of the decanter centrifuge.
Made a BOM on the doc
https://docs.google.com/document/d/1Eq32CS5Lr5qy8SvmcNOLg8heyqcrqfEfMRUhx3XsUl4/edit#

Meeting with Anthony to discuss second iteration of the Decanter centrifuge prototype. We used the report doc from the first tests.
https://www.amazon.ca/Adjustable-polishing-machine-fishing-12V3000/dp/B0965QSSBL/ref=sr_1_7?crid=2AY7OZ1LS49JJ&keywords=hollow+shaft+motor&qid=1654717312&sprefix=hollow+shaft+motor%2Caps%2C197&sr=8-7

We decided to iteratively go for a second design, redesign the screw, look at possibilities to only use one motor instead of two, better sealing for the barrel, and integrate other improvements ideas in the same doc.

Worked on the design roadmap with Tibi and Elie.
Glanced over some engineering papers about oil extractors.

Worked on the design roadmap with Tibi and Mario.
Glanced over some engineering papers about oil extractors.

Searching basic design parameters and discussing design with Elie, Tibi and Bernard

Bernard: Searching basic design parameters and discussing design with Elie, Tibi and Mario

Searching basic design parameters and discussing design with Tibi, Bernard and Mario

Searching basic design parameters and discussing design with Elie, Bernard and Mario

Scrum meeting with Tibi, Mayssam and others.

Design coordination meeting with Maysam, Mario, Tibi, and Elie.
We went over priorities, examples of designs.

Scrum meeting with Tibi, Mayssam and others.

Design coordination meeting with Tibi, Mario, Bernard.
We went over priorities, examples of designs.

Design coordination meeting with Maysam, Mario, Bernard, and Elie.
We went over priorities, examples of designs.

Design coordination meeting with Tibi, Mario, Bernard, and Elie.
We went over priorities, examples of designs.

Design coordination meeting with Tibi, Bernard, and Elie.
We went over priorities, examples of designs.

Writing Decanter Centrifuge testing report.

Updated the Deliverables doc, mostly the Design section.
https://docs.google.com/document/d/1g6DbV0mSqwU6rdLqyrv5Ctw_3cHamuPZLFXwajPkN4g/edit#

Updated the documentation for the Decanter Centrifuge
https://docs.google.com/document/d/1Eq32CS5Lr5qy8SvmcNOLg8heyqcrqfEfMRUhx3XsUl4/edit#

double checking things, finalizing, decided to reprint the barrel because the screw holes were a bit too big on the last one (the accuracy improvements caused the holes that previously grabbed the screw adequately to be bang on 2.9mm in diameter, which is not quite right for the screw to grab. The screw really has to grab, though. For the next revision these holes should be replaced with metal nuts.)

finishing screw, post processing to remove supports, sand, test for fit, all looks good.

reprint screw with better settings in sideways orientation

print screw in sideways orientation, remove support material, test for fit.

checking parts fit, dimensions are within suitable range, saving settings for future use, assemble bearings and other parts as far as I can to verify they fit

Re printing parts and adjusting parameters and options to achieve better accuracy. Circles appear to be much more susceptible to thermal contraction. Currently scaling objects up by 100.4 xy and using horizontal expansion of -0.1 combined with 4 wall layers and 80 mm/s print speed, 0.28 mm layer height, 70 degree build plate, skirt, most other parameters default is giving the best result. Some room for minor improvement, but probably no need to further improve. Thermal contraction appears to vary between brands of filament, but more so for circles vs. rectangular features. This variation between feature shapes is slightly baffling and a real problem. I am using PLA. Using "outer wall first" led to unnaceptable defects on the pulley teeth, however may be an acceptble subtitute for the horizontal expansion compensation factor on most parts. It leads to some under extrusion and some over extrusion on some areas of parts, it is unclear why.

review what has been printed, what needs to be done, add a table to the main doc, proceed with producing any remaining parts.

printing parts, updating master document

2 hours travel time to Montreal and back again to Cornwall. This is billed at an efficiency of 66 percent, because I also wanted to go to montreal for personal reasons.