Build Your Own iPod/MP3 Mini Speaker System
Listen and Share Your Music EverywhereBy Ben Godfrey
Skill level: Intermediate to Advanced Kit
Assembly Time: 2-3 hours
Do you love your music? Do you wish you could listen and share your music wherever you go? With this mini speaker system project, you can listen to music whenever you want: your dorm, your cubicle or at the beach. This is a great introduction to circuit systems, featuring an introductory amplifier circuit, a filter circuit and a simple enclosure. When you're done, all you need to do is add a 9V battery, plug in and play!
Drill and drill bits
Strong glue or epoxy
|1||22 Gauge Hookup Wire (Threaded)||818-5*|
|1||8Ω Speaker (treble)||TV-4171A-R|
|1||8Ω Speaker (bass)||FR-05202-01|
|1||Audio Amp Single Speaker 1 Channel||LM386N-3|
|1||8 Pin IC Socket||6000-8DW-R|
|1||Toggle SPST On/Off Switch||T100T1B1A1QN|
|1||9 Volt Battery Snap||BAT-SNAP-4|
|1||9 Volt Battery||ALK 9V 522|
|1||3.5 mm Male Audio Jack||AP-340-R|
|1||6' 3.5 mm Male/Female Audio Ext Cord||255-265|
|1||2.5" x 4.5" Protoboard||PCB-858-R|
|4||4-40 Machine Screw||28643|
|4||4-40 Hex Nut||36012|
|1||6" x 3.5" with 1.875" Core||H2851-R|
In audio terms an amplifier does exactly what its name suggests: it amplifies the current. That is, it takes an electrical signal and makes the signal stronger, and in the end, louder. An electrical signal that is passed by an amplifier comes out louder through the speaker than one that hasn't been amplified. Also, because the signal is strengthened by an amplifier, you can play that music through higher resistant speakers. This amplifier is a solid-state-hi-gain design and is intended to run through an 8 ohm speaker. As the amplifier schematic was originally designed by Ed Vogel and Blind Lightnin' Pete from MAKE Magazine, all credit goes to them for the amplifier design (below).
Before we begin to build the circuit for the amplifier, let's take a look at the protoboard. This board has a specific layout that should be understood before beginning to solder (unless you enjoy desoldering). The topology of this board is such that there are four columns in which the outer two columns are connected in rows, and the inner two columns are connected in rows. This should be taken into account when building the circuit.
As you can see in the photo above, there are four columns on the protoboard with the inner columns appearing slightly lighter than the outer columns.
On to the construction of the amplifier circuit!
Step 1: Soldering the ConnectionsPlace solder on the IC DIP socket in a way that none of the rows are connecting. This means that you need to place the IC DIP socket so that the pins are parallel with the columns and the IC DIP socket crosses the gap between one of the outer and inner rows. Also note at which end pin 1 will be located. If you don't do this, your circuit may not work due to putting the op amp in backwards.
Begin to build the circuit as described in the schematic. One trick I found particularly helpful was to make the circuit pin by pin. That is, I worked on the circuitry connected to pin 2 of the IC DIP socket, and then pin 3, and 4 then 5, etc.