SquarePi

A Raspberry Pi HAT that turns any Pi into a 2×30W hi-fi wireless speaker system.

One install command sets up the audio driver, music player, web UI, Bluetooth, DLNA, Spotify Connect, AirPlay, and a 15-band hardware DSP equalizer. After a reboot it's reachable at squarepi.local from any phone or browser — no app, no account, no cloud.

From square wave to every corner. — Sijah AK

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At a glance

Output	2×30W stereo Class-D
Audio quality	48kHz / 24-bit — automatic upscaling on all sources
Cost	Under $30 in parts
Protocols	7 — BT · DLNA · Spotify · AirPlay · USB · Radio · MPD
Setup	One command — sudo bash install.sh (Bluetooth + EQ UI included)
Control	Browser UI — squarepi.local, no app install
Cloud	None — fully local, no account, no subscription

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What it plays from

Protocol	How it works
Bluetooth A2DP	Pair any phone or tablet — no PIN, auto-pair, always discoverable
DLNA / UPnP	Stream from Windows Media Player, Kodi, VLC, or any DLNA app
Spotify Connect	SquarePi appears as a speaker in the Spotify app (Premium required)
AirPlay	Stream from iPhone, iPad, Mac — no Apple account needed
USB Drive	Plug in a drive — library auto-scans, no steps required
Internet Radio	Built-in streaming, hundreds of stations, no extra app
MPD clients	Any MPD-compatible app on any OS auto-discovers SquarePi

All sources can be active simultaneously — ALSA dmix mixes them at the hardware layer.

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SquarePi Audio Engine™

Every source — Bluetooth from a phone, MP3 from a USB stick, 44.1kHz FLAC from DLNA — passes through four automatic stages before it reaches the speakers.

1 — SquarePi Upscaler™

All audio is upscaled to 48kHz / 24-bit. The Pi's hardware clock is ~10× more accurate at 48kHz than 44.1kHz, making this the correct native operating rate.

2 — SquarePi Resampler™

Rate conversion uses SoXR — a polyphase resampling library used in professional audio tools. 44.1kHz converts to 48kHz via a 160:147 integer ratio at "very high" quality. Technical details →

3 — SquarePi Mixer™

Multiple sources share the output via ALSA dmix at 48kHz / S32_LE. Bluetooth and DLNA playing at the same time works without either pausing.

4 — SquarePi EQ™

15-band parametric EQ running inside the TAS5805M chip over I²C — no CPU involvement, no latency. Technical details →

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SquarePi EQ™

13 Presets

Preset	Character
EQ Flat	Neutral reference
EQ Bass Boost	Warm bass emphasis
EQ Treble	Bright, airy detail
EQ Vocal	Mid-forward, clear voices
EQ Night Mode	Gentle, low-fatigue listening
EQ Late Night	Boosted bass and air, low mids
EQ Rock	Punchy low-end, scooped mids
EQ Pop	Clear vocals, sparkly highs
EQ Jazz	Warm, slightly rolled-off
EQ Classical	Flat with gentle treble lift
EQ Club	Heavy bass, extended highs
EQ Hip-Hop	Deep sub-bass, forward mids
EQ Acoustic	Natural room character

All 13 presets are installed by default. Find them in myMPD under Scripts.

15 EQ Bands

Band	Freq	Band	Freq	Band	Freq
1	20 Hz	6	200 Hz	11	2 kHz
2	32 Hz	7	315 Hz	12	3.15 kHz
3	50 Hz	8	500 Hz	13	5 kHz
4	80 Hz	9	800 Hz	14	8 kHz
5	125 Hz	10	1.25 kHz	15	16 kHz

Range: ±15 dB per band. Runs in the TAS5805M chip — the Pi CPU is not involved.

Visual DSP Interface (installed by default)

Open http://squarepi.local:8081 for the full real-time DSP control panel.

• 15 fader sliders — DSP updates on every move
• Frequency response graph — live curve (boost above the zero line, cut below); drag any point to set a band directly, on desktop or touch
• Custom preset — save your own curve
• Analog Gain — hardware output trim (0 to −15.5 dB)
• Balance — L/R pan
• Mixer Mode — Stereo / Mono / Left / Right (crossfeed matrix via separate L2L / R2L / L2R / R2R gain controls)
• Save to chip — settings survive power cycles (alsactl store)

Plus a few quality-of-life touches:

• Colour themes — six palettes (Amber, Studio Blue, Phosphor Green, McIntosh Blue, Graphite, and a Daylight light mode); your choice is remembered per browser
• Now playing — the current track shows at the top, from MPD or from Bluetooth when the phone sends track info
• A/B compare — store two EQ curves and flip between them to compare by ear
• Unsaved indicator — flags when the live EQ differs from what's saved to the chip
• Preset sparklines — each preset button shows a mini preview of its curve shape

Terminal access via alsamixer → F6 → LouderRaspberry.

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Real-time Fault Monitor

Live readout from TAS5805M chip registers — available in the DSP UI (installed by default):

Fault	Meaning
Left / Right Channel OC	Output overcurrent — speaker short or overload
Left / Right Channel DC	DC fault — amp protection triggered
PVDD Undervoltage / Overvoltage	Supply voltage out of range
Clock	I2S clock fault
Over Temperature Shutdown	Chip too hot, output disabled
Warning 112°C / 122°C / 134°C / 146°C	Thermal warning thresholds

Green = clear. Red = active. All faults self-clear when the condition resolves.

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Control & UI

Interface	Address	Notes
myMPD web UI	http://squarepi.local:8080 · https://squarepi.local:8443	Mobile-optimised, always installed
EQ DSP UI	http://squarepi.local:8081	Installed by default (skip with --without-eq)
MPD (music apps)	squarepi.local:6600	Auto-discovered by M.A.L.P, MPDroid, Cantata
DLNA renderer	Appears as SquarePi in DLNA apps	With --with-dlna

No IP address needed — everything is reachable by hostname.

Sleep Timer

Built into every install — find in myMPD → Scripts:

Script	Action
Sleep_30min	Stop playback after 30 minutes
Sleep_60min	Stop playback after 60 minutes
Sleep_90min	Stop playback after 90 minutes
Sleep_Cancel	Cancel a running timer

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Setup

Requirements

• Raspberry Pi (Zero 2W · 3B+ · 4B · Pi 5 in development)
• Raspberry Pi OS Lite — Bookworm (Debian 12) or Trixie (Debian 13)
• SquarePi HAT connected
• Internet connection on the Pi
• SSH or local terminal

One-command install (recommended)

The default install includes Bluetooth and the EQ web UI — the two defining features — alongside MPD, myMPD, EQ presets, and the sleep timer:

curl -fsSL https://raw.githubusercontent.com/sijah/Square_PI/main/squarepi-installer/install.sh | sudo bash

Add optional protocols

DLNA, Spotify Connect, and AirPlay are opt-in:

# Add DLNA/UPnP renderer
... | sudo bash -s -- --with-dlna

# Add Spotify Connect
... | sudo bash -s -- --with-spotify

# Add AirPlay
... | sudo bash -s -- --with-airplay

# Everything (Bluetooth + EQ UI + DLNA + Spotify + AirPlay)
... | sudo bash -s -- --all

Skip a default feature

# Skip Bluetooth
... | sudo bash -s -- --without-bt

# Skip the EQ web UI (EQ presets in myMPD remain)
... | sudo bash -s -- --without-eq

If a BlueALSA package isn't available on your OS image, the installer logs a warning and continues without Bluetooth — the core install never aborts.

Clone and run locally

git clone https://github.com/sijah/Square_PI.git
cd Square_PI/squarepi-installer

sudo bash install.sh                      # Bluetooth + EQ UI (default)
sudo bash install.sh --all                # everything
sudo bash install.sh --without-bt         # skip Bluetooth

Optional: auto-reboot and custom hostname

sudo SQUAREPI_HOSTNAME=squarepi SQUAREPI_AUTO_REBOOT=1 bash install.sh

After install

sudo reboot

Verify audio card loaded:

aplay -l    # should show LouderRaspberry

Open myMPD: http://squarepi.local:8080

First boot defaults: Volume at 25%. EQ initialised to flat (all bands 0 dB).

Full setup guide with OS flashing, first boot, and troubleshooting →

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SquarePi vs Commercial Alternatives

	SquarePi	Sonos Era 100	Amazon Echo Studio
Price	< $30 parts	$249	$199
Cloud	None	Required	Required
Account	None	Sonos account	Amazon account
Data collection	None	Yes	Yes
Subscription	None	Some features	Some features
Protocols	BT · DLNA · Spotify · AirPlay · USB · Radio	BT · AirPlay · Spotify	BT · AirPlay
EQ	15-band hardware DSP	3-band app sliders	3-band app sliders
Audio upscaling	48kHz / 24-bit	None	None
Open source	Yes (GPLv3)	No	No
Setup	One command	App + account	App + account

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Who It's For

• Makers and hobbyists — open hardware, open software, real specs
• Non-technical families — one command, works from any phone browser
• DIY audio community — KiCad files, full BOM, Gerbers in Releases
• Privacy-conscious users — fully local, no account, no telemetry
• Anyone tired of subscriptions — music you control on hardware you own

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Hardware

Core Specifications

Parameter	Value
Amplifier chip	Texas Instruments TAS5805M
Output power	2×30W into 4Ω at 24V · 2×23W into 8Ω at 24V · 2×13W into 4Ω at 12V
Audio input	I2S digital from Raspberry Pi GPIO
DSP	Onboard TAS5805M — 15-band EQ, 3-band DRC, gain control, all via I²C
Supply	12–24V DC, barrel jack
5V rail	XL1509-5.0 buck converter (powers Pi too — no separate Pi power supply)
Form factor	Standard 40-pin RPi HAT, 65×61mm, 2-layer PCB
Outputs	Screw terminals: LP LN RN RP
Extras	IR receiver footprint, HAT EEPROM (auto Pi recognition)

DSP Technical Specs

Parameter	Value
THD+N	≤ 0.03% at 1W, 1kHz
SNR	up to 107 dB (A-weighted, 24V / 8Ω)
Dynamic range	up to 106 dB (A-weighted, 24V / 8Ω)
Crosstalk	−100 dB at 1kHz
Parametric EQ	15 bands per channel, full biquad
DRC	3-band, 4th-order
Volume range	+24 dB to −103 dB, 0.5 dB steps
Sample rates	32 / 44.1 / 48 / 88.2 / 96 kHz

Power Wiring

Supply	Min current	Output
12V	3A	~13W/ch into 4Ω
19V	3A	~20W/ch into 8Ω
24V	3A	~23W/ch into 8Ω

Check polarity before powering on. Use passive 4–8Ω speakers only. Never connect speakers while powered.

Speaker Terminals

Terminal	Connection
LP	Left +
LN	Left −
RN	Right −
RP	Right +

Thermal

Designed for heatsink-less operation. For long-term reliability:

• Use 12V with 8Ω speakers for cool continuous operation
• Avoid sustained high-volume with 4Ω speakers above 12V
• TAS5805M includes automatic thermal foldback — reduces output at high temperature, recovers automatically

Design Files

Hardware designed in KiCad. PCB fabricated at JLCPCB.

• Gerbers, BOM, KiCad project: GitHub Releases
• Driver: sonocotta/tas5805m-driver-for-raspbian

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Raspberry Pi Compatibility

Model	Status
Pi Zero 2W	Primary target — tested, recommended
Pi 3B+	Tested
Pi 4B	Tested
Pi 5	In development

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What Gets Installed

Always installed (base)

Component	Purpose
tas58xx kernel driver	I2S/I2C amplifier driver
Boot overlay	Enables I2S, loads SquarePi audio overlay
mpd	Music Player Daemon
mpc	MPD command-line client
alsa-utils	aplay, alsamixer, speaker-test
mympd	Mobile-friendly web UI
avahi-daemon	mDNS — squarepi.local on any network
exfatprogs	exFAT USB drive support
EQ preset Lua scripts	13 one-tap presets in myMPD Scripts
Sleep timer Lua scripts	30 / 60 / 90 min + Cancel in myMPD Scripts
squarepi-eq-init.service	Sets EQ flat on first boot, then disables itself

Bluetooth (default — skip with --without-bt)

Component	Purpose
bluez + bluez-tools	Bluetooth stack
bluez-alsa-utils	BlueALSA, routes BT audio to ALSA
squarepi-bt-agent	Auto-accept pairing, no PIN
squarepi-bt-setup.service	Keeps adapter discoverable and pairable after every reboot
/etc/asound.conf dmix + softvol	Shared ALSA output — BT and MPD play simultaneously; BT Volume control

EQ web UI (default — skip with --without-eq)

Component	Purpose
squarepi-eq-server.py	DSP web UI on port 8081
squarepi-eq.service	Systemd unit, starts after sound target
squarepi-alsa-restore.service	Restores saved EQ state at every boot

With --with-dlna

Component	Purpose
upmpdcli	UPnP/DLNA renderer, bridges MPD to DLNA

With --with-spotify

Component	Purpose
raspotify	Spotify Connect daemon

With --with-airplay

Component	Purpose
shairport-sync	AirPlay receiver

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Adding Music

Default MPD library: /var/lib/mpd/music

sudo cp -r /path/to/music/* /var/lib/mpd/music/
sudo chown -R mpd:audio /var/lib/mpd/music
mpc update

Internet radio: add streams in myMPD → Browse > Webradio.

USB drive: just plug it in. SquarePi auto-mounts it and it appears in MPD under usb — no SSH, no fstab. FAT32, exFAT, NTFS, and ext4 drives all work, any label or size. Unplug to remove it. (Manual/advanced mounting is still documented in docs/setup.md.)

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Branding / White-label Options

sudo SQUAREPI_HOSTNAME=myplayer \
     SQUAREPI_BT_NAME="Living Room" \
     SQUAREPI_BRAND_NAME="MyPlayer" \
     bash install.sh --all

Variable	Purpose
SQUAREPI_HOSTNAME	Pi hostname
SQUAREPI_BT_NAME	Bluetooth device name
SQUAREPI_BRAND_NAME	Name in installer banners
SQUAREPI_TAGLINE	Tagline in installer banner
SQUAREPI_AUTO_REBOOT	Set 1 to reboot automatically after install

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Troubleshooting

Audio card not found

aplay -l
dmesg | grep -i tas58
lsmod | grep tas

MPD not working

sudo systemctl status mpd
journalctl -u mpd -n 50
mpc status

If ALSA card name differs from LouderRaspberry, update /etc/mpd.conf:

device "plughw:<card-name>,0"

DSP UI not loading

systemctl status squarepi-eq
journalctl -u squarepi-eq -n 30
curl http://127.0.0.1:8081

Bluetooth not visible

rfkill list
sudo rfkill unblock bluetooth
sudo systemctl restart bluetooth squarepi-bt-agent squarepi-bt-setup

If pairing fails with Authentication Failed, remove old pairing:

sudo bluetoothctl
remove <MAC-address>
scan on

Pi does not boot after install

Mount boot partition on another computer and comment out SquarePi lines in config.txt:

# dtparam=i2s=on
# dtoverlay=tas58xx,i2creg=...

A timestamped backup is created automatically: config.txt.squarepi.bak.YYYYMMDDHHMMSS

myMPD not reachable

sudo systemctl status mympd
curl -fs http://127.0.0.1:8080

USB drive not visible in MPD

lsblk -f
findmnt /mnt/usb-music
sudo -u mpd ls /mnt/usb-music

Use UUID in /etc/fstab, include uid=mpd,gid=audio for FAT/exFAT, run mpc update after mounting. See docs/setup.md for full instructions.

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Uninstall

curl -fsSL https://raw.githubusercontent.com/sijah/Square_PI/main/squarepi-installer/uninstall.sh | sudo bash

Removes all SquarePi components. Prompts before deleting music data. Music files are not deleted unless confirmed.

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Documentation

Document	Contents
docs/audio-engine.md	How the audio pipeline works — upscaling, resampling, mixing, DSP EQ
docs/supported-protocols.md	Setup and usage for all 7 protocols
docs/setup.md	Full guide: OS flash → HAT → install → first boot → troubleshoot
ABOUT.md	Full project pitch for press and feature requests

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Contributing

Issues, pull requests, and forks welcome.

• Installer: single self-contained bash script — squarepi-installer/install.sh
• DSP server: plain Python stdlib — squarepi-installer/eq-server.py
• Hardware: KiCad files in Releases
• No build step — clone, edit, test on Pi

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License

GPL v3 — free to use, modify, and distribute. If you distribute a modified version, it must also be GPL v3 with source available. See LICENSE.

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From square wave to every corner. — Sijah AK