Prototype v1: Field Unit
Concept · A5 footprint (≈ 210 × 120 mm) · Indian temple stucco palette · every control is a part we own or have on order
Concept for review, not a final enclosure. Sizes follow the real parts (2.8″ LCD module, 45 mm faders, EC11 knobs, 0.96″ OLED).
The encoder spacing still has to match the Quad encoder boards. Tap or hover over a control to see which part and bus it uses.
Design ideas
- Radio you can see: a telescopic antenna and a dedicated radio window (the two-colour OLED, yellow status band over a blue frequency) with a larger TUNE knob, so the radio feels like part of the instrument rather than a menu.
- Game-pad navigation: 5-way switch plus REC and PLAY under the left thumb, MODE and SHIFT beside it, the way small handhelds such as Casio's SX-C1 sampler put game-controller buttons on top.
- Direct controls, few menus: each source has its own colour, its own fader and its own knob ring (the Quad encoder LEDs). The same colours run through the LCD lanes, in the spirit of "no menus, just buttons" pocket samplers such as the Stylophone VOICE.
- Pocket density, hand-sized parts: everything fits on an A5 plate while keeping real 45 mm faders and touch pads big enough for fingers (24 × 18 mm copper).
- Place on screen: the LCD footer shows where and when (GPS) with the tempo, because every capture is stamped with location.
Palette: Indian temple stucco
Taken from the painted stucco figures of South Indian temple towers (gopurams): a peacock-turquoise body with a vermilion and gold outline, and one temple colour per sound source.
| Colour | Hex | Used for |
|---|---|---|
| Peacock turquoise | #1F9A97 → #13706F | Body |
| Vermilion | #D9452B | Outline, REC, centre button |
| Lotus pink | #E75480 | MIC |
| Marigold | #F6A21A | SMP (sampler) |
| Krishna blue | #2A52BE | SYN (synth), MODE/SHIFT |
| Gold ochre | #E2A72E | RAD (radio), TUNE, mic grille |
| Parrot green | #5BB04A | PLAY, GPS |
| Lime-wash white | #FBFBF8 | OUT, labels, navigation cross |
Control map
| Control | Part | Bus / pin |
|---|---|---|
| Nav + centre | 5-way switch (P504) | MCP23017 GPA0–4 · Wire2 0x20 |
| MODE, SHIFT, REC, PLAY | Tactile buttons | MCP23017 GPB0–3 |
| Faders MIC SMP SYN RAD | Slide pots 45 mm (P4272) | ADS1115 A0–A3 · 0x48 |
| Fader OUT | Slide pot 45 mm | Teensy pin 40 |
| 4 knobs above the screen | EC11 on Quad encoder #1 | 0x49 |
| 2 knobs + TUNE | EC11 on Quad encoder #2 | 0x4A |
| Screen | ILI9341 2.8″ (P1770) | SPI1: 26, 27, 39, 38, 37, 36 |
| Radio window | SSD1306 OLED, two-colour | 0x3C |
| 8 pads | Copper on CAP1188 | 0x29 |
| Radio + antenna | Si4732 DIY | 0x11, RST 34, audio → LINE-IN R |
| Mic | Electret + MAX9814, or piezo contact mic (switch) | → LINE-IN L |
| MIDI HOST / USB-C | USB Host cable / Teensy USB | Keyboard in / computer, power, USB audio |
Open questions
- Encoder spacing is set by the Quad boards: measure them and adjust the two knob rows.
- Front panel material over the pads: touch works through 1–3 mm of plastic.
- Power bank outside the case, on the back: printed cradle or strap, cable slot for 2 short USB cables.
See also: Breadboard prototype v1 · Gallery · BOM
References for the design ideas: Casio SX-C1, Stylophone VOICE, Woovebox.
Oh My Ondas is a GPS-location-aware portable field recording and sampling instrument. Licensed under AGPL v3 (firmware), CERN OHL-S v2 (hardware), CC BY-NC-SA 4.0 (documentation).