The fourth step in the design thinking process is Prototype. This stage is where the team developed scaled down versions and experimented with specific features found within a potential product.  We decided to initially focus on a fruit basket that could sense when fruit like an apple or banana is removed or added to the basket and provide feedback to a server that could interact with a larger software ecosystem.

We first tested how software interacted with the different sensors to determine which might work with the features we were considering.  Then we played around with the load cell  and developed a "scale" to determine if the load balancing cell could detect weight differentials. 

Following the load cell tutorial at SparkFun, we assembled a testing rig out of scrap wood. To simulate a fruit basket's use and to test the calibration and data collection process, we used an apple and kitchen weights

We changed the code to calibrate the scale and to add a ring buffer such that the data would only be returned if there's a change in weight over a fixed set of data.

Next we built on that initial prototype. We used threaded rods to provide a breadboard area to mount the camera and the NVIDIA® Jetson Nano™ above the scale. The camera is placed to identify items below in the fruit basket.

Scale

Load Balancer

Scale with rods added