Feeding Experimentation Device (FED) 2.0

FED measures food intake in mice. It is battery powered and designed to be used in rodent colony caging.

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FED is a Feeding Experimentation Device for measuring food intake in mice. It is a 3D printed pellet dispensing device that operates with the following logic:
1) Dispense a 20mg food pellet and monitor its presence with a photo interrupter
2) Log the date and time when the pellet is taken by the mouse
3) Repeat

The data is stored to an SD card and can be analyzed after an experiment to understand feeding patterns over multiple days. FED is battery powered and small enough to be used in many experimental conditions, including rodent home cages.

FED 2.0 is a redesign of the original FED device developed by Katrina Nguyen and her colleagues in 2016, and published in the Journal of Neuroscience Methods. FED2.0 runs on an Adafruit Feather Adalogger M0, and uses boards and code from Adafruit, Paul Stoffregen's Time library, and Arturo Guadalupi's ZeroRTC library. FED is open source, released under the MIT license.

FED2.0 improves on FED1.0 in the following ways:

  1. Smaller, cheaper, and easier to build
  2. More reliable pellet dispensing
  3. Longer battery life - FED2 should last around 2 weeks on a charge.  This can be increased quite a bit with some hardware and code changes (message me if you want details) but we prioritized ease of build and use over battery life.
  4. FED2.0 has a screen!  

TODOs, as of 3/4/18:

  1. Collect and upload testing data on FED2.0 (update 3/6: this test has started - see logs!)
  2. Create and upload operating instructions
  3. Create and upload troubleshooting documentation
  4. Create an "Operant" faceplate for FED that includes 2 nosepokes so mouse can trigger pellets based on his behavior (in progress, I'll post a log soon).
  5. Implement wireless data transfer to watch data in realtime (in progress using Particle Photon and Blynk for visualization).
  6. Work on RFID for tracking feeding from multiple subjects (this is in progress but it's more complicated than we though!)

FED2 operating instructions.pdf

PDF with operating instructions - please comment and provide feedback!

Adobe Portable Document Format - 2.05 MB - 03/12/2018 at 18:25


Feather code - unzip and flash onto the Adalogger M0 with the Arduino IDE. Updated March 8, 2017

x-zip-compressed - 10.22 kB - 03/11/2018 at 03:30



All 6 STL files, updated 030418

x-zip-compressed - 266.12 kB - 03/04/2018 at 18:58


View all 17 components

  • Example FED2 data

    Lex Kravitz03/13/2018 at 16:29 0 comments

    We have recorded 6 FEDs for well over a week straight (they are doing great!).  Pellet data from these devices is downloadable here:

    Example FED2 data

    If anyone wants to discuss building analyses tools for this data (meal patterns, nigh/day feeding, etc) please message me!

  • Operating instructions

    Lex Kravitz03/12/2018 at 21:00 0 comments

    I just uploaded a document to the files section containing operating instructions.  Describes a few quirks like needing to re-flash to reset the date/time.  Maybe in a future build I'll come up with a workaround that doesn't require that but for now that's how it's done!

  • Commercially printing FED with Shapeways

    Lex Kravitz03/08/2018 at 19:06 0 comments

    We have access to 3D printers that work fine for printing FED, but I wanted to explore commercial solutions for this.  These may be of interest for people who don't have a 3D printer or who want to print multiple FEDs quickly.  So I ordered a complete FED from Shapeways and it arrived today.

    Quick price comparison: We estimate 1 complete FED costs about $8 in PLA filament for us to print, while printing a FED in the same material with Shapeways cost $100.41.  So it's a lot more $$, but they do nice work and it's very convenient.  The Shapeways FED parts look excellent, a bit nicer than what we print in our lab.

    Also, uploading parts to Shapeways allowed us to answer the question of how much it costs to print FED in different materials:

    Nylon? $253.32  

    Steel?  $728.57  

    14K Gold????  $71,746.13!  (Please send me photos if you go for the gold!)

  • Quick update!

    Lex Kravitz03/07/2018 at 22:26 0 comments

    We've been running 6 FEDs for 1 week and all have functioned well.  One drained its battery faster than the others, which may suggest that it has a problem dispensing that keeps the motor going longer than the others.  But 5 are perfect.  Figure 1. Example feeding pattern of one mouse:

  • First real world test of FED2.0

    Lex Kravitz03/04/2018 at 03:31 0 comments

    We built six FED2.0's last week, and after bench testing them we started them running with mice last Thursday.  I'll post an update here on how they are functioning in a real world test!

  • FED2.0 is online!

    Lex Kravitz03/03/2018 at 20:25 0 comments

    We published FED1.0 in 2016 and distributed it to ~10 labs.  After receiving feedback on this device over the last year we redesigned FED2.0 to address several issues.  This is the release and build instructions for FED2.0.  We look forward to comments so we can improve it further!

View all 6 project logs

  • 1
    Print out the six 3D parts

    The print needs to be of decent quality.  It is a mechanical pellet dispenser, so if your print is poor it may jam or not work correctly.  I printed these in PLA on a Sindoh 3DWox printer.  STL files located in the files area.  I'll also upload a link to the files on Shapeways shortly.

  • 2
    (optional) Spray the 3D parts with clear acrylic

    This is to protect them from mouse gross-ness.  Don't spray the pellet disk.  Also no need to coat the insides of the parts.  Let them dry for a couple days before putting them with mice. 

  • 3
    Add headers to the Adalogger M0 board and the Memory Display

    Solder straight male headers to the Adalogger board, instructions here: 

    Solder six 90 degree headers from Vin to CS pins on the Memory Display 

View all 11 instructions

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