Beginner+
Bluetooth Stereo Speaker
Follow a picture-first guide from loose modules to a tested rechargeable Bluetooth speaker, with exact terminals and meter checkpoints at every stage.
Safety first, always.
ElectroLab AI teaches theory, low-voltage electronics, and planning concepts. Mains voltage, switchboards, fixed wiring, high-current systems, and legal electrical work must only be performed by licensed electricians where required.
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Picture-first module build
Turn separate power, Bluetooth, amplifier, and speaker modules into one tested stereo system.
Bench time
2-4 hours
Typical parts
$35-$65 AUD
Power
1 protected 18650 cell
You finish with
Rechargeable 2 x 3 W speaker
Before the first wire
Know the build before you power it.
Read the printing beside every terminal. Similar-looking modules often use different terminal order.
Use a protected 18650 cell in a holder. Do not solder directly onto a loose cell.
Keep every speaker disconnected until the supply and output checks pass.
The PAM8403 speaker outputs are bridge-tied: L- and R- are not ground and must never be joined together.
Bill of materials
10 parts groups to gather
Check every spec
| Qty | Part | Exact spec | What it does | Inspect before use |
|---|---|---|---|---|
| 1 | Bluetooth audio receiver | 3.7-5 V module with L, R, and GND line outputs | Receives audio and produces a small stereo signal. | Find power input separately from L/R audio output. |
| 1 | PAM8403 stereo amplifier | 2 x 3 W class-D, 2.5-5.5 V | Raises the line signal to speaker power. | Identify VCC, GND, L/R input, L+/L-, and R+/R-. |
| 1 | Protected 18650 cell and holder | 3.6/3.7 V nominal, reputable protected cell | Stores energy for portable use. | No dents, torn wrap, rust, heat damage, or exposed metal. |
| 1 | USB-C 1S charger/protection board | B+/B- and OUT+/OUT- terminals | Charges one cell and disconnects serious over-current/under-voltage faults. | Confirm the board includes protection and is configured for the cell. |
| 1 | Inline fuse | 1 A fuse and insulated holder | Opens the battery output if the wiring shorts. | Fuse must sit close to OUT+ before thin hookup wire. |
| 1 | Power switch | SPST, rated above 1 A DC | Disconnects the audio boards from the battery output. | Use continuity mode to find the switched pair. |
| 2 | Full-range speakers | 4 ohm, 3 W or greater | Convert left and right amplifier power into sound. | Both should measure roughly 3-4 ohms DC and move freely. |
| 1 | Supply capacitor | 1000 uF, 6.3 V or higher electrolytic | Reduces supply sag and clicks near the amplifier. | Stripe marks negative; fit directly across VCC and GND. |
| 1 | Decoupling capacitor | 100 nF ceramic | Bypasses fast switching noise at the amplifier supply. | Fit close to the board power terminals. |
| As needed | Hookup and speaker wire | Red/black power pair plus short shielded or twisted audio leads | Carries power, line audio, and bridge speaker outputs. | No loose strands; heat-shrink every exposed solder joint. |
Build boundary
This guide covers a low-voltage, single-cell speaker. It does not cover loose multi-cell packs, bypassing lithium protection, or mains-powered amplifier supplies.
Part modules vary. Read the markings and datasheet for the exact board in front of you before applying power.