I. Group Members:
Yu Hin Chan
Herman Kwong
Ka Man Lai
II. Description:
The recorder-playing machine is composed of a musical keyboard, a fan, three servo motors and a recorder. When user play notes on the keyboard, the servo motors will move the hole covers and produce different notes accordingly. The fan is used to produce an air current into the recorder. User can select different volume levels, which are controlled by different fan speeds.
III. Components Interfacing:
i) Musical Keyboard: There are positive wires and negative wires coming out of the keyboard. When a key is pressed, one of the positive wires and one of the negative wires will be connected together, we take the wires as bits and process them.
ii) Servo Motors: Servo motors use Pulse Coded Modulation. The angle that the shaft turns is determined by the duration of a pulse that is applied to the control wire.
iii) Fan: A circuit with a relay and a transistor is built, so that with a fixed voltage supply, the circuit can provide different voltages across the fan and allowing it to run at different speeds.
IV. Difficulties:
One difficulty that we have encountered is that after we have dissembled the electronic piano (which is also a hard task because we do not have a screw driver of the right size!), we do not have any documentations or specifications of the components. We had spent some time to figure out how signals are generated and which key generates what signal through which wires.
Another problem is that, notes were not played at the right pitch at the beginning due to air leakage at the recorder holes. We mange to use Tack and craft stick to cover the holes tightly in the end.
