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Mechatronics Learning Studio

 

 

CoinBot

Hasan Alper Hepguvendik, Alexander Helal, and Jeremy Gruttner, Department of Mechanical Engineering, University of Ottawa  

 

Objective

CoinBot plays Heads or Tails in a best 2 out of 3 match with a player. CoinBot will flip the coin using a solenoid attached to its hand, recognizes the outcome by using phototransistor with reflective properties of colors, and responds accordingly with his voice.  Tallies and announces the final score of the match.

Circuits

Circuit for Reading the Coin

 

It contains a white LED to supply constant brightness to the phototransistor for getting more accurate and consistent readings.

 

The coin which was flipped by the solenoid slides down in front of the photo transistor. In our project the coin has two sides that are painted. Black (tails), white (heads). (White reflects more, black reflects less) Phototransistor reads the intensity of light reflected by the side. And lets current pass according to the intensity of light reflected towards the phototransistor by coin. Reading varies between 0 and 5 V. (0 is very dim and 5 is very bright light)

 

Circuit to Check for Coin on Coin Flipper Solenoid

 

It is just a phototransistor used as a switch. Since, only thing it needs is absence of light to confirm the presence of coin, it eliminates the frustration of buttons.