Final Design

Our final design consists of 2 springs (Sampling and Isolation) attached to a foam insert inside a PVC pipe. When the sampling spring is pushed off the hook, it closes around the animals hair and pulled into the tube. The isolation mechanism is retarded by the friction caused by the foam block. To further protect the hair sample, a door is pulled up over the end of the tube to protect from insects.

To remove the hair sample after triggering, a researcher will pull down the foam insert with the attached string. The sampling spring can then be unclipped and brought back to basecamp with the hair entangled in the coils for DNA analysis. A new spring can then be inserted and the trap reset.

This design is superior to previous design concepts in that the failure modes are more favorable, the sample is more protected and this design is more easily made with off the shelf components.

Build Guide/User Manual

Previous Concepts

Roller Design

This concept consists of a roller with a hair sampling surface affixed to half of the roller. When an animal presses on the roller, it would spin due to an internal spiral torsion spring. The spinning motion would be the main method of collecting a hair sample. Isolation would be achieved by having the final position of the hair sampling surface be facing into the main housing.

This design concept was abandoned do to unfavorable failure modes and difficulty to manufacture. It would be possible for an animal to leave a sample without triggering the isolation mechanism. This contamination would be unacceptable. Also, the tolerances required to make this device functional would make it very difficult to make without precision instruments.

Lid Design

This prototype consists of a traditional sampling surface attached to a button. When an animal pressed on the brush, the button will trigger releasing the door to close around the brush. However, this design was abandoned due to its failure modes and possible for animals to damage the device.

With this surface it would be possible for an animal to leave hair on the brush without triggering the lid to close. This would allow for a different animal to trigger the trap and leave a contaminated sample. Also, after talking to animal researchers we figured it would be possible for bears to open the box contaminating the sample, or break the lid off the device.

Cart Design

This concept is similar to our final design, but a cart with traditional snagging surface is used instead of a spring. Again we ran into the issue of collecting a sample without isolating it. The isolation method used here was adapted to be used in our final design.

Picture Frame Design

This was our first instance using a spring to collect a sample. In this concept, a spring is stretched over a picture frame between a screw and hook. When an animal presses on the spring, it will slip off the hook and collect a sample. If positioned correctly, the spring will swing down into an isolation box preventing any DNA contamination.

This concept was combined with the cart design for our final solution. Our final design protects the sample from insects, UV degradation, insects and moisture unlike this prototype. This design could still be a good solution if used in the correct environment as it is very inexpensive and simple to create. However, in harsher environments the hair samples would be more vulnerable to the elements which is unfavorable to the specific researchers we consulted with.