FIELD

An independent field-recording radio for the M-VAVE FM-1, powered by Radio Aporee. Browse the world, choose a country or state/province, and listen through a static globe UI.

Open the website · USB web installer · Download 0.1.19-alpha

Status

This is experimental firmware. The original alpha was reported working on an FM-1, and the playback-buffer update was reported to improve cutouts substantially. 0.1.19 makes SELECT’s live mix control overdub strength for Radio and USB. In Layer, 0% preserves the existing sample unchanged; 100% keeps the original 50/50 blend; intermediate values add a quieter layer while retaining more of the old sound. You can adjust it during recording. ALGORITHM remains a monitor-only mute, so quiet monitoring still permits overdubbing at the chosen mix. Replace capture stays independent of monitor level. USB sampling, saved location caches, all four sample lengths and the display mirror remain. Software tests pass; hardware testing is still needed.

For installation, leave FIELD running normally; the web installer switches modes automatically. It also accepts a loader already on screen. Allow up to 45 seconds for discovery. The new loader re-enumerates USB after 12 idle seconds if necessary, with no reconnects during an active flash session. An older loader already running uses its old behavior until this release is staged from running firmware.

The header shows a three-bar battery level, or USB when powered by an active USB host.

Controls

In favorites, turn SELECT to move, then press SEL or PLAY to replay that exact recording. Favorites survive power-off. Up to 16 fit in a separate 3,840-byte flash object; long URLs and credits can fill it sooner. A full list asks you to remove an entry. These are online bookmarks: playback still requires WiFi and the recording to remain available.

The sampler holds one mono ADPCM clip (one playback voice) in a 24 KiB bank reclaimed from the removed effects. It survives returning to the main screen, changing recordings, and reopening ARP. REC again stops capture early; otherwise it stops at capacity. ARP's OCT buttons transpose; keys use C4 as the original pitch. In Loop hold, releasing the triggering key stops playback. Loop latch keeps playing after release and across screens; tap its key again or PLAY in ARP to stop. Slice divides the trimmed range into 4, 8, 16 or 27 equal sections at a common pitch. PRESETS selects the count while in Slice mode; higher keys repeat the sequence when fewer than 27 slices are selected. It starts at 27 on boot. Changing the count stops the current sample voice and retains the clip. SEL cycles One shot → Loop hold → Loop latch → Slice → One shot. PLAY auditions/stops the clip. Leaving the sampler finishes capture without saving it. The selected live input stays audible in ARP by default. Turn ALGORITHM left to mute its monitor and right to restore it at the chosen SELECT mix. This switch does not mute the sample or stop capture. A short fade avoids an abrupt gain change. Leaving the editor restores full live playback; the editor remembers its mix and mute until reboot.

To capture USB-C audio, connect FIELD to a computer with a data cable and select FIELD as the computer’s playback/output device at 44.1 kHz, 16-bit stereo. This uses USB device audio, not a USB-host connection to another USB peripheral. Send audio from the computer, open ARP, and press ENV until the header says Sampler / USB. Press REC to capture or EDIT for Layer, then REC to overdub. Stereo input is averaged to mono in the existing sample bank.

USB capture works without WiFi. Incoming silence records normally; missing USB frames pause capture. The editor reports when USB audio is unavailable and refuses an empty start. Live mix also sets Layer overdub strength; ALGORITHM mute does not affect capture, and Replace ignores both monitor controls. Source selection is locked while recording; stop with REC or SAVE before switching. Leaving the editor finishes capture and restores radio monitoring; the same sample remains playable on the keyboard. Source selection resets to Radio at boot; saved clips keep their audio and rate regardless of origin.

The USB receive ring adds 2 KiB of heap, reserved before WiFi allocations. No sample, compressed-stream or PCM buffer is reduced. The optional USB display mirror remains available with its existing low-memory guard. The computer can still record FIELD’s output over USB; avoid routing that return back into FIELD unless an audio feedback loop is intended.

Press SAVE in ARP to store one clip, including trim, pitch/octave, level, playback mode, slice count and recorded rate. SAVE during capture finishes it early and saves. The display confirms “Sample saved.” Another SAVE replaces this single slot. New captures and edits are temporary until saved. The saved clip restores at boot and when the editor is reopened with no clip. Previous saved clips migrate when saved again; both sample banks commit only after payload verification. New expanded clips require 0.1.17 or later. Saving briefly interrupts audio while the flash is programmed. Failed writes retain the previous saved version. Normal FIELD updates preserve the slot; restoring other firmware or erasing user data can overwrite it.

Turn PRESETS in ARP outside Slice mode, before recording in REPLACE, to select quality/time. Turn right for more Lo-fi; left selects higher quality.

The right side of the status row shows the selected rate/capacity; Ready shows the current clip's actual length. Changing PRESETS does not stretch or retune an existing sample: the setting applies to the next new capture. It cannot change during recording. Slice mode retains PRESETS for slice count; press SEL to leave Slice before selecting recording quality.

Overdubs use the existing clip's rate and duration. In LAYER with a clip, PRESETS reports “Layer uses clip rate”; use REPLACE to choose a new rate. SAVE stores the actual captured rate, and it restores on reboot at normal pitch. Existing 8 kHz saved clips remain compatible. New clips need FIELD 0.1.17 or later. Existing clips retain their recorded rate and pitch.

Press EDIT in ARP to select LAYER, then REC to overdub the live recording onto the existing clip. It makes one pass over the full original clip at its original speed, with SELECT’s live mix controlling overdub strength: 0% keeps the old clip byte-for-byte; 100% blends old/new 50/50 for headroom. Intermediate settings add a quieter layer and retain more of the original. Adjustments apply during recording. ALGORITHM remains a monitor-only mute. The old clip is audible during the pass; keyboard audition resumes afterward. Trim, pitch, octave, slice and playback settings are retained. The clip's length stays the same at its recorded rate. Network buffering pauses capture.

REC again stops early and leaves the remaining old audio intact. SAVE stops capture and stores the merged result in the existing single saved slot. EDIT switches back to REPLACE for a new recording; it defaults to Replace after reboot. If no clip exists, Layer makes a normal first capture. A layer is temporary until saved. The LFO filter remains available and is not baked into capture.

The sampler uses a static landscape with compact knob readouts and no keyboard activity display. SELECT sets live mix; ALGORITHM mutes independently. Sample playback gain now reaches 200%, with a default of 173%. Overall output gains 1.5× before the master control, with stereo-linked peak limiting. Capture stays dry and unboosted for overdub headroom. This increases digital level, not the amplifier's physical maximum. Tap FX to set filter tempo; the player briefly displays BPM and the FX LED pulses on the beat.

USB live display mirrors the 240×240 screen in desktop Chrome or Edge. Connect with FIELD running normally. Move the computer window to a monitor or capture it in OBS; fullscreen and PNG save are provided. This is a read-only USB-MIDI pixel stream, not HDMI, DisplayPort or a UVC webcam. No direct USB-C monitor connection is supported. Its 3,928-byte heap object exists only while subscribed; at least 8 KiB of heap reserve must remain. Disconnect, cable removal or a six-second missing heartbeat releases it. The installer asks this site’s viewer to close its ports before taking USB ownership. Compressed audio and PCM buffers retain their previous sizes.

LFO opens an independent stereo filter after the live/sample mix. The filter starts off at boot and activates on its first visit; it stays active when leaving the page. ALGORITHM left bypasses it, right enables it. Its state is temporary. K1 sets cutoff (80–6,000 Hz), K2 resonance, K3 modulation depth (zero gives a manual filter), and K4/SELECT speed. SEL cycles low-pass, high-pass, band-pass. EDIT toggles free speed (0.05–8 Hz) / sync (8, 4, 2, 1, 1/2, 1/4 beats per cycle). FX on this page enables sync and taps tempo; other FX taps update the shared tempo too. The header shows BPM. The static river scene and compact readouts match the sampler. Filter bypass and cutoff/resonance changes are smoothed. Samples remain playable on this page; OCT skips within the current region, REC saves favorites, ARP opens the sampler, ENV opens the same sampler editor. Capture remains before the filter, so the captured source stays dry. The filter needs a small amount of state and uses no sample audio history.

Delay/Reverb and the old held-key effects are removed in this sampler-focused build. Their memory now belongs to the longer clip. Pitch-independent time-stretch is not implemented; the pitch knob still changes playback speed and pitch together.

Near is anchored when EDIT enables it and survives power-off. It does not drift with each skip. An uncached Near anchor scans the location index once, potentially taking three minutes or longer; later skips and reboots reuse its saved cache. EDIT disables it; choosing a region or worldwide random from SAVE also disables it. It never widens the radius silently if no locations match.

The first uncached location selection downloads Aporee's index and takes about three minutes, longer on a weak connection. FIELD saves a 32-location reservoir per cached world/region/Near context in eight rotating flash sectors. Later boots and exhausted batches reuse those locations and fetch only their playlists; recordings remain online. The worldwide cache is retained when other contexts rotate out. An uncached or evicted context requires another scan.

Press GLO → SAVE to scan again and replace the current context's cached locations. This is a bounded location reservoir, not the full world index: without refresh, location diversity is limited to its saved batch. New recordings at those locations can still be selected. Writes occur only for a changed batch, with CRC validation and commit last; interrupted refreshes retain the previous saved copy.

The catalogue contains 162 countries and 1,560 states/provinces with recordings. It uses a snapshot of Aporee coordinates and generalized Natural Earth boundaries. Offshore/unclassified points and newly added locations remain available worldwide. It is a browsing aid, not a precise border map. See full notes and limitations.

The device screen and USB product name are FIELD.

Build

The platform is vendored in base/; no submodule setup is needed. Use Linux x86-64, Python with Pillow, JieLi's pi32v2 toolchain, and AC79 SDK AC79NN_SDK_V1.2.1_2023-12-13. SDK binaries are not vendored.

python3 -m pip install Pillow
AC79_SDK=/path/to/fw-AC79_AIoT_SDK JIELI_TOOLCHAIN=/path/to/toolchain \
  python3 base/tools/build.py app --release 0.1.19-alpha

This produces app/build/field-0.1.19-alpha.fwsc. Platform setup is documented in the upstream README and base. The generated region catalogue is included; Shapely/NumPy and the boundary source are needed only when rebuilding that catalogue.

Validation

• Hardware build checks: image, RAM, pool headroom and register access.
• Every compressed geographical lookup compared with the generated mapping.
• Country/state filtering, one-location regions, and worldwide-cache restoration.
• Simulator menu navigation, playback completion, and controls.
• Simulated 1.5-second network pauses at 128/320 kbps without rebuffering; a seven-second pause causes one refill and resumes the same recording.

See APOREE.md and tests/ for details. Software tests do not establish real-world WiFi reliability on every FM-1.

Website

The main page flashes directly in place, with an inline confirmation and progress display. Recovery and crash-report tools are below it. The complete static landing page and USB flasher live in docs/. GitHub Pages publishes main → /docs. All links are relative so the site works under this repository's Pages path. Firmware downloads, checksums, and previous alphas are included.

Credits and licences

Built on fm1-radio by Charles Vestal, fm1-base, and felucca-bsp, from Felucca by Leo Kuroshita (Hügelton Instruments). See source provenance. Source is MPL-2.0 with third-party components under their own licences; all notices are retained in LICENSING.md and LICENSES/.

Recordings come from Radio Aporee and retain their contributors' individual licences. Geography is made with Natural Earth (public domain). FIELD is independent of, and not endorsed by, Radio Aporee or M-VAVE.