An operant conditioning chamber for rats.
The operant chamber or "Skinner box" was invented by American psychologist B. F. Skinner during the early 1930s. It is used in psychological laboratories to study in a controlled situation the effects of environmental variables on the probability of a relatively simple response known as operant. In a simple arrangement, operant learning can be studied by presenting a reinforcing event (e.g., food or water) every time a rat presses a metal lever. In these particular chambers, rats can also be trained to press the lever only when a stimulus (e.g., a light) is presented. Numerous principles of behavior have been discovered in the operant chamber. Many of these are the basis for behavioral psychotherapy.
These inexpensive 3D-printed operant chambers are used as teaching tools during the undergraduate courses of Learning and Behavior Analysis imparted by Dr. Rogelio Escobar at the National Autonomous University of Mexico (UNAM).
Read more about this project: http://3dprint.com/106669/3d-printed-lab-equipment/
All parts are printed in PLA because it is a non-toxic material. A layer height of 0.3 mm and a 20% fill density are recommended for the panels. A 0.2 mm resolution is recommended for the lock mechanism and hinges. No support material is necessary. I like printing the grid-holding parts using white PLA and the rest of the parts using gray PLA, but you could use any color you like.
A file in AutoCAD format (Acrylic_Walls.dwg) includes three walls for the chamber. These must be laser cut in 3-mm clear acrylic. Red lines in the drawing represent cuts.
You will need also the following materials:
15 – Stainless steel rods (8 mm diameter x 210 mm in length) . These can be obtained from any 3D printer-part supplier.
1 – 10 mm LED with holder. This LED is used as houselight. I like Adafruit’s diffused white LEDs (https://www.adafruit.com/products/846). An LED Plastic holder (https://www.adafruit.com/products/2171) fit perfectly in the chamber.
4 – #6-32 x 3/4 in. Machine Flat Phillips Screws with nuts. These are used to attach the parts holding the steel rods to the base of the chamber.
24 – #6-32 x 1/2 in. Machine Round Combo Screws with nuts. These are use to secure the panels and the hinges.
1- LED illuminated pushbutton - 30 mm round (https://www.adafruit.com/products/492). This is not actually used as a button but as a light above the lever. It is useful to present a visual stimulus.
3 - M3 x 10 mm screws. These keep the water/food tray in place.
E6000 glue. The parts holding the steel rods, the lock mechanism, the small flange that keeps the door locked, and the water/food tray parts require glue. The panels can be glued together to make the chamber stronger.
Follow the images to assemble the chamber. Blue parts are 3D printed, gray parts are laser cut acrylic, and white parts are stainless steel. Some 3D printed parts require sanding to facilitate assembly.
The water pump to deliver liquid reinforcement can be found at http://www.thingiverse.com/thing:1247624
The lever can be found at: http://www.thingiverse.com/thing:1246025
This chamber is compatible with the Arduino-Visual Basic interface designed for operant research. The interface is described at: http://www.ncbi.nlm.nih.gov/pubmed/25649099
This project was funded through a grant from DGAPA UNAM (PAPIIT IN304615)