This week I successfully got the sonic sensor, which was the other option for a sensing platform, working in the casing. I soldered wires to the relevant pins of the sensor and mounted the sensor to a small piece of cardboard attached to the top of the tampon side of the dispenser. I quickly discovered that it was hard to properly line up the sonic beam to hit the weight on top of the tampons, but I solved this problem by adding some extra cardboard to the back side of the weight. This doesn’t affect the operation of the machine but makes it easier for the sonic sensor to see. After hooking up an LCD, I was able to easily see the readings from the sonic sensor. I determined that the sensor has a blind spot within about the first 9 inches or so of its reading, but after that it works like a charm and with many fewer wires and mess than the hall sensors from last week. This week, my goal is to turn the inches reporting into more relevant numbers and come up with a solution to properly handle the sonic sensor’s blind spot. Finally, I got the Pro Trinket, an Adafruit micro-controller with most of the same guts as the Arudino in a much smaller package, working (as you can see in the final image). It is harder to debug on, but it will be used in the final product due to size constraints.