EchoBox MIDI Looper — User Guide

A hardware MIDI recorder and looper for musicians. No technical knowledge required.

First Time Setup
Understanding the Buttons
Basic Operation
Loop Modes
Seeking During Playback
Display Information
LED Colour Guide
WiFi File Management
Tips & Tricks
Troubleshooting
File Naming

What This Device Does

The EchoBox MIDI Looper records your MIDI performances in real time and plays them back as seamless loops — all with four physical buttons, no computer required.

Feature	Detail
Recording	Starts automatically when you play MIDI notes
Storage	SD card with date/time stamped filenames
Loops	Seamless infinite loops with less than 2ms gap
Upload	Load `.mid` files via WiFi
Display	OLED shows state, channel, and playback progress

First Time Setup

1. Set the Clock

The device timestamps every recording. Set the clock once on first use via WiFi mode (see WiFi File Management for full details):

Hold buttons A + B while powering on
Connect to WiFi ESP32-MIDI-Looper (password: midi1234)
Open http://192.168.4.1 → click "Set Device Time"
Press any button on the device to exit and reboot

Note: The clock is battery-backed (CR2032 on the RTC module) and keeps time when the device is powered off.

Understanding the Buttons

The device has 4 buttons, from left to right:

┌────────┬────────┬────────┬────────┐
│   A    │   B    │   C    │   D    │
│  LOOP  │  PREV  │  PLAY  │  NEXT  │
└────────┴────────┴────────┴────────┘

Button Functions at a Glance

Button	While Idle	While Browsing	While Playing	While Recording
A — LOOP	Cycle loop mode	Cycle loop mode	Stop playback	No effect
B — PREV	No effect	Go back (−1, −2...)	⏮ Rewind 1s	No effect
C — PLAY	Enter browse mode	Play selected track	Stop playback	End recording now
D — NEXT	No effect	Go forward	⏭ Skip forward 1s	No effect

Button A — LOOP

Cycles the loop mode. The LED on button A shows the current setting:

LED Colour	Mode	Behaviour
🔴 Red	OFF	Record only — no automatic playback
🟡 Yellow	ONCE	Play once after recording, then stop
🟢 Green	INFINITE	Loop continuously until you stop it

Button B — PREV / REWIND

While browsing: steps backward through recordings (−1, −2, −3...)
During playback: jumps backward 1 second per press — press multiple times for a bigger jump

Button C — PLAY

While idle: enter browse mode (LED C turns yellow)
While browsing: start playing the selected track
During playback: stop immediately
During recording: end the recording right now (instead of waiting 5 seconds)

Button D — NEXT / FORWARD

While browsing: steps forward through recordings, past 0 into uploaded files (+1, +2...)
During playback: jumps forward 1 second per press — press multiple times for a bigger jump

Basic Operation

Recording Your First Loop

Set Loop Mode — Press A (LOOP) until the LED is GREEN (infinite loop)
Start Playing — Play any MIDI notes. Recording starts automatically. All 4 LEDs turn red.
Stop Recording — Stop playing and wait 5 seconds (auto-saves), or press C (PLAY) to stop immediately.
Loop Starts — Playback begins automatically and loops forever. Press A or C to stop.

Tip: The loop is seamless — there is less than 2ms of silence between iterations.

Playing Back a Previous Recording

Press C (PLAY) — LED C turns yellow (browse mode)
Press B or D to navigate:

Track Number	Meaning
−1, −2, −3...	Your recordings, newest first
+1, +2, +3...	Uploaded MIDI files

Press C (PLAY) again to start playback
Press A (LOOP) or C (PLAY) to stop

Seeking During Playback

While a track is playing you can jump to any position:

Press	Action
B once	Jump back 1 second
B three times	Jump back 3 seconds
D once	Jump forward 1 second
D three times	Jump forward 3 seconds

Any stuck notes are silenced automatically each time you seek. To stop playback entirely, press A or C.

Stopping Playback

Press A (LOOP) or C (PLAY) — all MIDI notes are silenced immediately.

Note: B and D seek through the track rather than stopping it.

Loop Modes Explained

Press A (LOOP) to cycle through the three modes:

	Mode	Behaviour
🔴 RED — Loop OFF	Record only	Saves the recording but does not play it back. Good for capturing performances you'll browse and play later.
🟡 YELLOW — Loop ONCE	Play once	Plays the recording once after capture, then returns to idle. Good for quickly previewing what you just played.
🟢 GREEN — Loop INFINITE	Loop forever	Loops continuously until you press A or C. Perfect for live performance. Each loop is seamless (less than 2ms gap).

Display Information

During Playback

PLAY L:INF
CH:05  42%
SD:1000HRS

Line	Meaning
Line 1	Current state (`PLAY`) and loop mode (`L:INF` = infinite)
Line 2	MIDI channel (`CH:05`) and playback progress (`42%`)
Line 3	SD card free space shown as estimated recording hours

While Browsing

WAIT L:INF
CH:05 #0000
REC:-3

Line 3 shows your current position: REC:-3 = 3rd-most-recent recording, UPL:+2 = uploaded file #2.

Screen Saver

After 30 seconds of no activity the display and LEDs turn off to protect the screen.

MIDI recording continues normally during screen saver mode. Any button press or incoming MIDI note wakes the device instantly.

LED Colour Guide

Loop Mode (Button A)

Colour	Mode
🔴 Red	Loop OFF — record only
🟡 Yellow	Loop ONCE — play once
🟢 Green	Loop INFINITE — loop forever

Device State

Colour	When
🔴 All four LEDs red	Recording in progress
🟢 Button C green	Playback active
🟡 Button C yellow	Browsing recordings
🔵 All LEDs blue	Browsing uploaded files
🔵 Cyan	WiFi mode active
⚫ All off	Screen saver active

WiFi File Management

Use WiFi mode to set the clock, upload MIDI files, or manage your recordings.

Entering WiFi Mode

Turn off the device
Hold buttons A + B (the two leftmost buttons)
Turn on while holding — display shows: Join wifi / pw=midi1234 / 192.168.4.1
On your phone, tablet, or computer connect to WiFi: ESP32-MIDI-Looper (password: midi1234)
Your browser should open automatically — if not, go to http://192.168.4.1

What You Can Do

Action	Notes
Set device time	Required on first use and after replacing the backup battery
Upload MIDI files	`.mid` format — choose which MIDI channel to use
Upload native files	`.txt` format — direct upload, no conversion needed
Download recordings	As native `.txt` or converted to standard `.mid`
Delete recordings	Individual files or bulk delete
View all files	Listed with timestamps

Using Uploaded Files

Uploaded files appear as positive track numbers (+1, +2, +3...). Browse past 0 with D (NEXT) to reach them. Blue LEDs indicate you are on an uploaded file. Play them exactly like your own recordings.

Exiting WiFi Mode

Press any button on the device — it reboots to normal mode.

Tips & Tricks

Quick Live Loop

Set loop to 🟢 GREEN (infinite)
Start playing — recording starts automatically
Stop playing and wait 5 seconds
Loop starts immediately

Precise Recording Stop

Press C (PLAY) during recording to end it at exactly the right moment, rather than waiting for the 5-second silence timeout.

Building a Set List

Upload your backing tracks as .mid files via WiFi. They appear as +1, +2, +3... Browse to them during a performance with D (NEXT) and press C (PLAY) to start.

Skipping Through Long Recordings

Use seek to navigate without listening all the way through. Press D several times to skip forward quickly, B to go back. Each press moves 1 second.

Layering Ideas

Record a rhythm loop on GREEN mode. While it plays, press C to stop, then record a second loop that plays along. Both are saved separately — reload either one later via browse mode.

Troubleshooting

"Nothing happens when I play MIDI notes"

Check the MIDI cable direction: MIDI OUT → Device MIDI IN
Check your MIDI controller is powered on
Check the SD card is inserted

"Time is wrong on recordings"

Enter WiFi mode (hold A+B at power-on) and set the device time
If the time resets every power cycle, the CR2032 backup battery may need replacing

"Display is blank"

Screen saver is active — press any button or play a MIDI note to wake it
Check the device is powered on

"Can't connect to WiFi"

Make sure you held A+B while powering on (device must be in WiFi mode)
Look for network name: ESP32-MIDI-Looper
Password: midi1234
Try forgetting the network on your device and reconnecting

"Uploaded MIDI file won't play"

Make sure the file is standard MIDI format (.mid)
Try re-uploading with a different channel selection
Some complex MIDI files may not convert perfectly

File Naming

Recordings are named automatically with a sequence number, date, time, and MIDI channel:

Example: midi_00042_20260201_143022_CH05.txt

Part	Example	Meaning
`00042`	42nd recording	Sequence number
`20260201`	2026-02-01	Date (YYYYMMDD)
`143022`	14:30:22	Time (HHMMSS)
`CH05`	Channel 5	Last MIDI channel used

Files are stored on the SD card and can be copied to a computer at any time.

Safety Notes


✅	Recordings save to SD card automatically — nothing is lost if you power off
✅	Clock is battery-backed — timestamps survive power cycles
✅	No stuck MIDI notes — all notes are silenced when you stop or seek
✅	SD card is removable — plug it into your computer to back up files
✅	WiFi mode is read-only until you click delete

Quick Reference

Button	Idle	Browsing	Playback	Recording
A — LOOP	Cycle loop mode	Cycle loop mode	Stop	—
B — PREV	—	Previous track	⏮ Rewind 1s	—
C — PLAY	Browse mode	Play selected	Stop	End now
D — NEXT	—	Next track	⏭ Skip 1s	—

WiFi Mode: Hold A+B at power-on · Network: ESP32-MIDI-Looper · Password: midi1234 · Address: http://192.168.4.1

Screen Saver: Display off after 30s inactivity · Press any button or play a note to wake

Enjoy looping! 🎹🔁