Portable DIY Bluetooth Speaker

Portable DIY Bluetooth Speaker

(Makita or Parkside – Powered by ZK-TB21)

Turn any speaker tower into a high-power portable sound system that leaves store-bought Bluetooth speakers in the dust. At the heart of the build is the ZK-TB21 amplifier module, capable of drivingtwo 50 W columns and a 100 W subwoofer with crystal-clear sound and impressive punch.

The best part? It runs on the power tool batteries you already own—Makita, Parkside, or compatible—so the build cost stays low while delivering impressive performance. With 21 V from these batteries, the amplifier delivers serious volume, perfect for garden parties, workshops, or any outdoor event.

Key Features

• Works with Makita or Parkside tool batteries 150 W total output (2 × 50 W + 1 × 100 W)
• Based on the proven TPA3116D2 chip
• Compact, rugged, and DIY-friendly
• Outperforms typical commercial Bluetooth speakers

Variants

Choose the configuration that best suits your project:

All-in-One Board – Fully integrated for a quick and tidy build. Modular Setup – Separate components for easier customization and fitting into compact speaker columns.

Parts Required

• 1 × ZK-TB21 amplifier module (original TPA3116D2 IC)
• 8 × M3 brass inserts
• 2 × 6.3 mm male crimp terminals (13.8 mm long)
• Cables for battery-to-amplifier connection

(Both Parkside and Makita versions use the same battery crimp terminals.)

Pro Tip: If you’re using only one column, connect it to either the L or R channel and enable “mono” mode in your smartphone settings for balanced sound.

Acknowledgments Special thanks to the following contributors for their valuable parts and designs:

guppyk2 — Amplifier case
Felix_350928 — Makita battery adapter 
Teddyminator_35325 — Parkside battery adapter

Your contributions have greatly helped make this project possible.

Category: DIY