Problem Statement Build a device for use in research that compares the ability of young and old monkeys to sense tastes and smells (stimuli). Once the monkey has chosen a door based on the stimulus, the other door must be inactivated.

Design Objectives Flexible stimulus capability Present two clearly distinct options Choice must be final Sensitivity …To present stimuli -- Both tastes and smells Allow monkey to choose between the two. One may be BLANK! Both options must clearly be separate and correlate to a specific stimulus * No “looking behind door #2” or getting a reward for a wrong choice! If he’s right, gets a treat! To facilitate fast and efficient testing of several monkeys Sensitive enough for a monkey’s timid touch, but not so much that it can be tripped accidentally by a random bump or tap. Constructed of metal; something that can be repeatedly washed and sterilized and can withstand abuse from operation and an occasional drop to the floor. Simple for BOTH the monkey to use and for the researcher to reset.

Design Objectives Provide a reward Readily movable between cages Durable, non-corrosive Simple operation - as automated as possible

Past Accomplishments Constructed a working prototype Mechanical door-locking mechanism Moveable from cage to cage Sized to fit cage Durable construction

Past Accomplishments Problems Doors opened sideways Cumbersome locking mechanisms to reset Edge of doors could be harmful to monkeys

Mechanical Design

Mechanical Design (locked tripped) Ta Da!!! The Mark-1 prototype (complete with Sarah’s gay 12-inch ruler from God knows where…) Body casing constructed of sheet aluminum. Components of the door-locking mechanism are made of brass. The mounting plate can be seen on the bottom half of the device.

Alterations to Mechanical Design Switch door setup - hinge on top Eliminate metal ‘lip’ Install an internal divider Remove locking mechanism Rounded door edges Training device for use in teaching the monkeys how to operate the device (those 700 exposures we talked about) How to associate door with reward, etc… Complex locking mechanism is NOT crucial at this time… “Short Term” implies by next week… Switch from side-opening to top-opening; Can do this simply by removing old doors and adding new ones. Get rid of the sharp metal ‘lip’ between the bottom edge of each door opening and the floor of the device. Not only can it be dangerous, it can hinder the monkey’s ability to use the device. Add an internal divider to prevent the monkey from reaching through to the other side: say, to the left-side cup from the right side door. They’re smart little buggers!

Electrical Design Same form as mechanical design Door hinges on top Electrical locking mechanism Photomicro sensors Solenoid locks Battery powered – 9 volt Simple Easy reset button On/Off switch

Electrical Design We found that the overall shape and dimensions were acceptable. Do modifications to create a training device that can go into immediate use. (Move doors, cut off metal lip, add a divider.) Long Term: What do we want to do??? Which avenue (mechanical? Electrical?) do we wish to pursue and why?

Comparison Mechanical Design Advantages: No electrical demand, easy to fix, high durability Disadvantages: Cumbersome device to reset, more moving parts These are ideas to improve the LONG-TERM (testing) device. Feel free to remove any of these. Should probably pick three to go over with some level of detail (as much as we can spare during an 8-minute presentation)

Comparison Electrical Design Advantages: Simplicity of operation, automatic Disadvantages: Higher cost, electrical dependence

Future Work Attach mounting plate for cage Add a divider plate and food trays Indicator lights for correct door choice Test the prototype with monkeys Train and test monkeys with the product

Acknowledgements Special Thanks to: Thomas Roberts – for assistance in prototype design and development Clients: Goran Hellekant, Vicktoria Danilova Advisor: Professor John Webster