This stage of our project required a workable prototype; one that can be used in a real-world setting. We enacted various interactions with experienced stakeholders and incorporated their feedback to better our product. Below are the various ways that we exhibited thorough use of our integrated human practices, and how that positively affected our product development.

(a) The Electronic System

Our design uses the TCS230 color recognition sensor module to detect the biosensor's color changes and determine the likelihood of detecting gold. An Arduino nano (ARM-based) microcontroller interpreted the color sensor and displayed the 'likelihood' of gold being found – onto an Organic Light-Emitting Diode (OLED) screen. Furthermore, a 5V relay module controls the U.V kill switch. The U.V switch was a 220V AC led strip. The color indicators were simulated by coding RGB LEDs. All electronic components were soldered onto a perforated board and placed in a suitable and robust package.

(b) Biosensor Containment System

The biosensor will be contained in a number of capsules. The aforementioned biosensor will be placed within a stake-like structure, with various perforated points for increased surface area (and hence interactions) with the particles in the soil. The stake will be plunged several feet into the ground and used for detection of gold and its pathfinders [As3+ and Fe2+]. Several CAD models were developed at various stages of the project, until the best version was used for the physical prototype.

A pictorial representation of the hardware interpretation

Biosensor containment prototype

Electronic system for prototype

Summary of working prototype

The two LED lights represents detected particles. At any point in time each LED will glow either pink, blue or yellow. This is used to simulate the color indicator associated with a particle detection. The color sensor senses the two colors being read, and prints unto the OLED, the probability of finding gold.

Below is a video of the prototype and its functionality