FED3 – Feeding Device

Founding developers Katrina Nguyen, Lex Kravitz, Mohamed Ali and Filipe Carvalho

Accessories for FED3 – Feeding Device

Founding developers Katrina Nguyen, Lex Kravitz, Mohamed Ali and Filipe Carvalho

This device was developed by the Kravitz lab at Washington University in Saint Louis to study feeding and obesity in mice. The Kravitz lab is interested in basal ganglia circuits and how their function changes in obesity and addiction. The lab is a strong supporter of open-source science.

This is a fully assembled FED3 device. For Electronic kit only, please visit FED3 – Feeding Device – Electronic Kit

The Feeding Experimentation Device version 3 (FED3) is a small stand-alone pellet dispensing device for feeding mice and/or for training mice on operant tasks. FED3 ships with 12 built-in programs but most importantly, FED3 is open source and can be programmed by users to achieve new functionality. For an introductory video, click here. 


FED3 automatically quantifies feeding with high accuracy and temporal resolution. It is home cage compatible, and can measure both food intake and feeding patterns over multiple days. The FED has a small well giving access to dispensed food pellets. A pellet in the well is detected with a photoelectric sensor. Removal of the pellet triggers the dispense of the next pellet. Pellet delivery is stored with the timestamp on an SD card. The device is battery driven. No cable or computer connection is required for operation. It uses a rechargeable battery that lasts about a week between charges.

The FED provides a huge advantage over the most common method for monitoring food intake involving the manual weighing of food, which is labour intensive, and does not give feeding patterns. 

The FED3 Quick Start Instructions are very helpful once you have the device ready to go. 

The built in screen provides feedback to the user while all behavioural events are logged to an inserted microSD card. The built-in programs include:

  • Fixed-Ratio 1, 3, and 5
  • Progressive Ratio
  • Extinction
  • Light tracking
  • Optogenetic self-stimulation
  • Free-feeding
  • Time-restricted feeding

Programs can be easily modified to other tasks.

CONTENTS OF THE SET (fully assembled and tested)

  • PCB with display and Adafruit Feather M0 Adalogger
  • Stepper motor
  • Micro SD card
  • Micro USB cable
  • 3V Lithium Coin Cell Battery
  • Short battery extension cable
  • Assembled device with FED3 Lid, FED3 disk, FED3 housing, FED3 nose, FED3 door, FED3 base, magnets inserted

The unit comes fully assembled.

Parts not included in the kit :


ONLY 20mg pellets must be used with FED3. Smaller pellets might be hard to detect in the well and larger pellets might block the dispensing mechanism. More information can be found here


Matikainen-Ankney BA, Earnest T, Ali M, Casey E, Wang JG, Sutton AK, Legaria AA, Barclay KM, Murdaugh LB, Norris MR, Chang YH, Nguyen KP, Lin E, Reichenbach A, Clarke RE, Stark R, Conway SM, Carvalho F, Al-Hasani R, McCall JG, Creed MC, Cazares V, Buczynski MW, Krashes MJ, Andrews ZB, Kravitz AV (2021). An open-source device for measuring food intake and operant behavior in rodent home-cages. eLife

Documentation Source Code Forum

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