The world of embedded systems can be a daunting one, but not when tackled one small step at a time! Throughout the semester, students have been bombarded with new and exciting concepts like Pulse Width Modulation and serial communication. In an effort to further grasp those concepts and flex their scientific minds, Team 6 currently works to assemble a basic machine implementing those very practices. The machine itself has a simple goal — distribute playing cards to players around a table for any number of games; but the production hosts its own underlying objectives. With this automated card dealer, the team aims to advance its experiences with external sensors, servos, 3D modeling tools, as well as the coding which coincides with each of their functionalities.
The initial plan seemed simple at first, but later experimentation indicated approaching complications (to be further discussed later). The round card dealer would listen for a knock on a table. Once the knock was registered and triangulated, the machine would point itself towards the source of the knock, and fire a card in that direction. Three vibration sensors would listen for the knock, and would use the difference in time between their independent signals to calculate the required angle of knock-origin. However, the sensitivity of the vibration sensors proved troublesome (again, to be discussed in the next post).
The firing mechanism is nothing more than a DC motor with a rubber wheel strapped to it. The wheel sits below a deck of cards. When prompted (when the machine is pointing towards the player), the A3BU forces the motor to jolt; and a card is quickly rolled away from the deck and on to the table. Gravity then feeds the next card to the wheel for the next distribution. A 3D-printed apparatus or some sort of wooden structure would be needed to affix the motor and cards in place; but otherwise, there is no major challenge.
The machine itself is divided into two parts — the base and the rotating distributor. A servo will be inserted into the base which will then drive the distributor. The machine will require a full 360 degrees of rotation; however, the servo is only capable of 180 degrees of rotation; so a complement of gears are needed to grant the additional turning span: one fixed to the servo itself, with a larger (2-to-1 ratio) gear attached to the rotating distributor. Ideally the machine would rotate clockwise continuously as it fires the cards; but that would pose complications for the wires (we can’t have a tangled mess now, can we?!). To compensate, the machine will merely perform its deals for a 360 degree span, then return to 0 degrees (re-winding itself) and continue dealing.
The next post will further explore how the vibration sensors were tested, what problems the team discovered while testing, as well as the team’s solution to accurately distributing cards to the proper player 🙂