DIYVE

Diyve is an open source DIY dive computer built on a RP2040. Learn more at diyve.org.

WARNING

Experimental project not intended as a primary or sole dive computer.

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What it does

• Records depth and temperature at 1 Hz to an SD card during dives
• Displays live depth (ft), temperature (F), elapsed time, and max depth on an e-paper screen
• Exports dive logs to UDDF 3.2.0 for import into Subsurface and other dive log software
• Four screens navigated with two buttons: Menu, Dive, Logs, Settings
• Real-time clock keeps accurate timestamps even when powered off

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Hardware

Bill of Materials

#	Part	Role	Price
1	Raspberry Pi Pico (RP2040)	Main MCU - dual-core ARM Cortex-M0+	$15
2	MS5803 pressure sensor	Depth + temperature via I2C	$70
3	DS3231 RTC	Accurate timestamps	$8
4	Waveshare 1.54" e-paper (200x200)	Display	$18
5	SD card breakout	FAT filesystem logging	$7
6	SD card	Storage	$10
7	LiPo battery	Power	$8
8	TP4056 LiPo charger	Charging	$6
9	Schottky diode	Reverse-polarity protection	$6
10	Slide switch	Power on/off	$9
11	2x momentary buttons	Navigation (TOP) + select (SIDE)	$7
12	Perfboard (52x72.5 mm)	Custom PCB base	$5
13	Pin headers	Connections	$8
14	Wire	Wiring	$13
15	GoPro housing	Waterproof enclosure	$19
16	Two-part epoxy	Sealing	$6
-	RP2040 Debug Probe	Flashing (dev only)	$30

Total (excluding debug probe): ~$215

GPIO Pinout

Buttons

GPIO	Function
GPIO 28	TOP button - navigate (active low, pull-up)
GPIO 27	SIDE button - select / long-press (active low, pull-up)

I2C Sensors

GPIO	Function
GPIO 2	MS5803 SDA (I2C1)
GPIO 3	MS5803 SCL (I2C1)
Default SDA/SCL	DS3231 (I2C0)

SD Card (SPI0)

GPIO	Function
GPIO 16	MISO
GPIO 17	CS
GPIO 18	SCK
GPIO 19	MOSI

E-Paper Display (SPI1)

GPIO	Function
GPIO 10	CLK
GPIO 11	MOSI
GPIO 13	CS
GPIO 6	DC
GPIO 7	RST
GPIO 8	BUSY

All pin assignments are defined in src/include/diyve_pins.h.

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Firmware

Language: C Build system: CMake + Pico SDK 2.2.0 Output: diyve.uf2 / diyve.elf

Dependencies (fetched automatically via CMake FetchContent)

• no-OS-FatFS-SD-SPI-RPi-Pico - FatFS SD driver (carlk3)
• pico-ds3231 - DS3231 RTC driver (antgon)

Prerequisites

• Pico SDK 2.2.0 installed and on PICO_SDK_PATH
• CMake >= 3.13
• ARM GCC toolchain (arm-none-eabi-gcc)
• OpenOCD with CMSIS-DAP support (for flashing)
• Python 3 (for RTC sync after flashing)

Build

./build.sh

This runs cmake -B build -S . followed by make -C build/.

Flash

./program.sh

This builds, flashes via OpenOCD + CMSIS-DAP, and automatically syncs the RTC from your PC's clock over UART.

To use a different serial port:

cmake -B build -DSYNC_PORT=/dev/ttyUSB0
cmake --build build -t flash

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Source Layout

src/
  main.c                          - init: stdlib, GPIO, RTC, MS5803, EPD, then GUI loop
  include/diyve_pins.h            - all GPIO assignments
  ms5803_i2c/                     - pressure sensor driver, 2nd-order temp compensation
  dive_logger/                    - FatFS SD logging, 15-byte binary records
  display/                        - EPD init + unit conversion helpers (C -> F, m -> ft)
  gui/
    gui.c                         - screen framework
    screen_menu.c                 - Menu screen (clock, pressure, SD status)
    screen_dive.c                 - Dive screen (live depth/temp/time/max)
    screen_logs.c                 - Logs screen (browse .bin files)
    screen_settings.c             - Settings screen
  vendor/epd_waveshare_1in54/     - Waveshare driver + GUI_Paint + fonts 8-24px

tools/
  dive_log_to_uddf.py             - binary log -> UDDF 3.2.0 XML
  sync_time.py                    - sync RTC from PC over UART on boot

mechanical/
  main_holder.scad                - main housing (52x72.5 mm)
  button_holder.scad              - button T-slot mechanism
  pressure_sensor_enclosure.scad  - waterproof sensor box
  plastic_clip.scad               - wrist attachment clip

test_data/                        - real dive logs from prototype testing

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Dive Logging

Dives are logged at 1 Hz as 15-byte binary records to .bin files on the SD card.

Record format: <HBBBBBff

• uint16 year
• uint8 month, day, hour, minute, second
• float32 temperature (C)
• float32 depth (m)

Depth calculation:

gauge_pressure = abs_pressure - (101325 Pa + 200 Pa offset)
depth_m        = gauge_pressure / (1025 * 9.81)

Water density: 1025 kg/m3 (saltwater)

Button timing:

• Poll: 50 ms
• Debounce: 150 ms
• Long-press threshold: 1000 ms

E-paper refresh: partial mode (~100 ms vs full ~1 s)

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Exporting Dive Logs

Convert a binary log to UDDF for Subsurface or other dive log software:

python3 tools/dive_log_to_uddf.py -i dive_004.bin -o dive_004.uddf

Output is UDDF 3.2.0 XML, importable directly into Subsurface.

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Mechanical

The enclosure is a GoPro housing sealed with two-part epoxy. OpenSCAD source files for all custom-printed parts are in mechanical/.

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License

MIT - see LICENSE.