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open-ephys / commutators

Active coaxial commutator for electrophysiology
https://open-ephys.github.io/commutator-docs/
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SPI Commutator Feedback from Jon #5

Closed cjsha closed 1 year ago

cjsha commented 1 year ago
  1. The slip ring holes should be 10-32 tap holes
  2. 10-32 bolt must not extend below bottom (<=8mm long)
  3. Slip ring gear inner hole too small: should be 7.8mm
  4. The big square hole for the motor wires to come through should be expanded to 24x50mm
  5. There are two 1/4-20 mount holes that are blocked by the motor.
  6. Should the motor just be covered by the case?
  7. Motor gear hole too small. 4.9mm diameter -> 5.1 mm diamter hole for tolerance
  8. Thin down the wall where the teensy PCB contacts the wall of the enclosure.
  9. The USB hole is the correct size but not the correct location.
  10. Move the rib further from the teensy its basically touching it right nwo.
  11. Reset button hole is in slightly wrong position. Also, the holes height can be reduced by 1.5 mm.
  12. Mor thickness on back plate (screws holding pcb are too close to surface). At least 1mm.
  13. Because there is very little to align to on the rotor shaft of this slip ring, make the gear with a flange to give it more of a shaft to align on.
cjsha commented 1 year ago
  1. I changed these holes from ones that are meant for M5 tap (4.2mm diameter) to ones that are meant for 10-32 tap (4.0386 mm diameter). I’m curious: why 10-32? I understand UNF gets you more threads but UNC is usually more common
  2. I redesigned the enclosure for ¼” long screws. Slip ring flange thickness is 2.34mm so (1/4-2.34/25.4)*32=5.05. This engages 5 threads.
  3. It is already 7.8mm in CAD. I increased it to 7.9mm.
  4. This will be taken care of by point 6
  5. I added the step motor we’re actually using into the CAD and enclosed the motor. This means I need to find somewhere else to put mounting holes (not finished yet)
  6. The whole motor is enclosed and inserted through the space occupied by the teensy/control panel (not finished yet but you can kinda see if you like how it looks from the below photos)
  7. I changed this hole from one that is 5mm diameter to one that is 5.1mm diameter. The D-edge is 2.05mm from the center.
  8. Wall is 1mm thick where the teensy goes
  9. Moved it +1mm on the y-axis (double checked with the kicad pcb file). Where does it need to go on the x-axis? (look at attached photo for reference coordinate system)
  10. No rib. I thickened these walls anyway per point 12
  11. Hole’s height (defined by the distance from the front panel PCB has been reduced from 3mm to 1.5mm. I moved the cutout +1mm in the y-axis (double checked with the kicad pcb file)
  12. I thickened outward and made a lip in which the PCB rests recessed. 0.5mm clearance around the PCB. 1mm thick lip. For a total of 1.5mm added thickness. I made the lip because thickening outward makes it such that the enclosure outline doesn't match the PCB outline. I need to thicken outward because thickening inward doesn't add material thickness where we need it.
  13. Both gears or just slip ring shaft? Idea: do you want gears with set screws so the assembler doesn’t have to glue? Then these can be replaced? (not finished yet)

image image

All the points marked with "not finished yet" describe fixes that aren't reflected in the above two screenshots

jonnew commented 1 year ago

These changes have been addressed in #7