Design your own docking station. This board presents a fantastic and highly motivating opportunity for pupils from KS3 through to post-16 to design and make their own sound systems. This low cost stereo amplifier can run from either batteries or an inexpensive PSU. The project provides an angle for all interests:
• Product design (1) use conventional resistant materials for the loudspeaker enclosures – just treat the amplifier as a simple plug-in black box;
• Product design (2) – use any one of the vast range of new materials available – concrete, ceramics, plaster, textiles …….
• Graphic design (1) – transform the external look of speaker enclosures by using printed materials
• Graphic design (2) – fabricate the loudspeaker enclosures using folded card methods – e.g., flat pack speakers
• Electronics – build the amplifier using the kit option or design and build one to a different specification
• Science/acoustics – design the enclosure with particular reference to acoustic criteria
Application notes: Any music source that drives a small earpiece is suitable for this project. The amplifier is fitted with a 3.5mm socket so that a standard lead from MP3 player etc. can simply be plugged in. An external socket can be soldered to the board. Volume is controlled at the player end itself.
Power requirements: The amplifier can be used with a wide range of batteries – 3V to 6V. Batteries capable of supplying higher currents give better sound and less distortion at high volumes: a three AA battery pack is ideal. Any PSU designed for audio applications is also ideal. Battery snap is included.
Loudspeaker requirements: The amplifier can be used with any size loudspeaker in the 4 – 8 ohm range. The use of lower impedance speakers accentuates bass sound – but these are less common. If more bass is required, one method is to use two 8 ohm loudspeakers connected in parallel for each channel.
Available as a kit of parts that require soldering or as a complete assembled board.
Board size: 34 x 30mm
Minimum supply voltage: 3V (4.5V recommended)
Maximum supply voltage: 6V (exceeding this maximum will damage the circuit)
Output power: approx. 1W per channel at 6V with 8Ω speakers
Speaker impedance: 4Ω or 8Ω suggested
Includes moulded battery snap for connecting to battery box with snap terminals or alternatively, a battery box with integrated switch can be used (not included).
It is worth either installing an ON/OFF switch or making sure your batteries are disconnected when not in use as this circuit will continue to draw current.