results

Overall, our project was able to complete the desired task (coin sorting and counting) but on a smaller scale and speed from what was originally envisioned. The coin sorter could only efficiently sort a hand-full of coins without jamming or becoming too clogged up in the coin bins. However, multiple trials showed that our creation was able to accurately display the total value of deposited coins if the sorting process was completed without error.

The results of our test trials show that the sensor, circuit, keypad and computation aspect of the project worked quite well. Coins that passed through the line-break sensors were registered by the handyboard accurately incorporated into our value computation code. The keypad and game also functioned as planned.

The area that required the most attention and troubleshooting was the mechanical design aspect of our project. A DC motor that was affixed to the mouth of the main collecting funnel was originally meant to regulate the flow of coins entering the system. We found, however, that the motor drew too much current while it was stalled and shorted out the handyboard. Although this problem may have been avoided by using a relay, it was eventually omitted in our final design. Its lack of gearing provided little torque and too much speed. In hindsight, it may have been better to use a stepper motor to regulate the coin flow.

Another issue that arose in our mechanical design was jamming. We were able to create funnels and tubing which were generally efficient in directing the flow of coins but occasional jamming of coins still occurred at the mouth of some funnels. Also, larger coin bins and more holes would have increased the speed and capacity of the coin sorting process.

Finally, the DC motor driving the agitator shaft could not initially overcome the friction between the agitator rods (rubber windshield wipers) and coin bins (Rubbermaid plastic). This was fixed by elevating the agitator rods off the bin floor. However, this caused some coins to slip under the agitators, which dampened the whole sorting efficiency. Use of brushes or some other low friction material may have solved this problem but time did not permit us explore these possibilities.