FEDs that I built from scratch don’t work well

[Yuhui Sunny Luo]

Hi everyone!

I built two FEDs by following the instructions on hackday.io, but testing them in the mouse home cages yielded unsatisfying results, compared to the FEDs that I assembled from 3D parts printed from Shapeways and electronic kits from Open Ephys. The FEDs that I built from scratch easily get pellets jammed and ends up with mouse being starved (I only used free feeding mode). After testing it manually without mouse, I suspect the problem is caused by the not optimal positioning of the nosepiece. There is a gap (although small) between the steel nosepiece and the photo-interrupter (see the first picture attached). This probably leads to either the pellets being not detected in the port and then more pellets get delivered (then cause the jam), or the pellets drop (and a small jump in the port) leads to a pellet retrieval count. 

Unfortunately I cannot push the PCB board more forward (so that the photo-interrupter is in line with the nosepiece, just like the second picture attached) because of the height of the Neopixel. The PCB board soldered by Open EPhys doesn’t have the problem because the Neopixel is kind of integrated into the PCB so the height is reduced. 

Could someone help to verify if it’s really the nosepiece positioning caused the problem? If so, could we have a more user-friendly and updated housing .stl 3D printing file for the users who build from scratch? 

The parts I used:

• PCB printed from OSHPARK: v5.5 Aug 2019
• Housing printed from Shapeways: Aug 2021
• Nosepiece printed from Shapeways: Sept 2020

Best,
Sunny

-----------------
Yuhui (Sunny) Luo

Pronoun: she/her/hers

Graduate Student in Biology Ph.D. Program
Root Lab & Zuniga Lab
University of California, San Diego (UCSD)

[Lex]

Hi Sunny!

I think you're correct in what the issue is.  It's critical that the pellet is detected by the pellet well or FED3 will continue trying to dispense more pellets, which will lead to jams. 

It would be best for you to edit the FED3 design yourself to fit your DIY electronics. Here is the link to the editable 3D design files.  I would use the negative "Box" tool to remove material where it is hitting your NeoPixels and try re-printing (see photo).  

As a fix for the ones you've already built, I would suggest using a file or electric drill to remove material from the inside of the 3D print until the electronics fit.  That will also inform what edits you need to make to the 3D design.  Good luck!

-Lex

  

--
You received this message because you are subscribed to the Google Groups "FEDforum" group.
To unsubscribe from this group and stop receiving emails from it, send an email to fedforum+u...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/fedforum/40c0a6af-79b4-4796-be4e-428eb1953f4b%40Spark.

[Yuhui Sunny Luo]

Hi Lex!

Thank you very much for your advice! I used a drill to remove the part of the housing that’s covering the neopixel, but doesn’t work well. I switched to use a Dremel to remove the piece. Then I found that with that piece removed, it actually didn’t help much to put the photo interrupter in line with the nosepiece. I then realized that it’s actually the bump (see the circled in the attached photo) designed to place in the screw that’s causing the problem. It doesn’t fit with earlier versions of DIY PCB because at that location there is no screw place yet, and the bump touches the bumped solder that solders the motor breakout in place. So I used Dremel to cut that bump on the housing, and now the PCB fits well into the housing! I ran a manual 200 pellets test and also a test in mouse home cages over ten days, the FEDs did their job well now. I will edit the housing .stl files to reflect that change if I’m building more "OG FEDs”, and I will post the edited file here in this thread. 

Best,
Sunny

On Sep 24, 2022 at 10:46 AM -0700, Lex <lex.k...@gmail.com>, wrote:

Hi Sunny!

I think you're correct in what the issue is.  It's critical that the pellet is detected by the pellet well or FED3 will continue trying to dispense more pellets, which will lead to jams. 

It would be best for you to edit the FED3 design yourself to fit your DIY electronics. Here is the link to the editable 3D design files.  I would use the negative "Box" tool to remove material where it is hitting your NeoPixels and try re-printing (see photo).  

<Untitled.png>

As a fix for the ones you've already built, I would suggest using a file or electric drill to remove material from the inside of the 3D print until the electronics fit.  That will also inform what edits you need to make to the 3D design.  Good luck!

-Lex

  

[Lex]

Thanks for posting back!  That screw standoff was added for the latest OEPS design.  On the TinkerCAD link the black housing in the "older models" area does not have this standoff.  So you can download/edit that one.  I'm also attaching an STL of that part.  Glad you figured this out!