These guides collect the precise parts list, wiring, assembly order, and first-test
checks in one place. Each step has a reserved photo position so the same guide can grow
into an illustrated build manual without changing the sequence.
These are DIY devices. Inspect every solder joint, use the pinouts below, calibrate and
compare against trusted equipment, and do not rely on a new build for diving until it
has been checked with known gas.
Nitrox analyser
LilyGo T-Display S3 build
Use the Nitrox Analyser product page for firmware and the live wiring diagram; this page is the complete bench-build sequence.
1 × LilyGo T-Display S3 — bare board, without fitted pin headers or a housing
1 × ADS1115 ADC module
1 × galvanic O2 cell and 1 × connector matched to that cell
1 × single-cell 3.7 V LiPo with the 1.25 mm plug matching the LilyGo battery socket
1 × small square, 6 mm-high tactile momentary push button
1 × 22 kΩ resistor and 1 × 10 kΩ resistor
12 × 6 × 3 mm neodymium magnets
M2 screws and M2 heat-set inserts, in the quantity and screw length specified by the released housing revision
Printed housing parts, short insulated wire, heat-shrink, solder, and strain relief
Pinout at a glance
O2 cell +
ADS1115 A0 / AIN0
O2 cell −
ADS1115 A1 / AIN1
ADS1115 power
LilyGo 3.3 V and GND
ADS1115 I²C
GPIO17 SCL, GPIO18 SDA; ADS1115 ADDR to GND
Momentary button
GPIO3 to GND
USB detect divider
USB 5 V → 22 kΩ → GPIO13 → 10 kΩ → GND
Battery
LilyGo BAT+ / BAT− through its matching 1.25 mm connector
Prepare the housing parts.Print the released housing set or order a printed set when available. Install the M2 heat-set inserts with a controlled iron and fit the magnets with their polarity checked before the final press-fit.
Step 1 photo coming soonHousing, inserts, and magnets
Dry-fit the electronics.Fit the LilyGo board, ADS1115, O2-cell connector, battery lead, and button without soldering. Confirm the display, USB-C access, sensor opening, and lid clearances before committing anything.
Step 2 photo coming soonDry-fit before soldering
Wire and mount the ADS1115.Connect the ADS1115 to 3.3 V and GND, then SCL to GPIO17 and SDA to GPIO18. Tie ADS1115 ADDR to GND. Keep the O2 signal path short and away from battery and USB wiring.
Step 3 photo coming soonADS1115 I²C wiring
Connect the O2 cell.Wire the cell connector positive lead to ADS1115 A0 and negative lead to A1. Do not power the galvanic cell. Add strain relief so the connector cannot flex the ADC pads.
Step 4 photo coming soonO2 connector and ADC inputs
Add the button and USB-detect divider.Wire the 6 mm tactile button between GPIO3 and GND. Wire USB 5 V through 22 kΩ to GPIO13, then 10 kΩ from GPIO13 to GND; never connect USB 5 V directly to a GPIO.
Step 5 photo coming soonButton and resistor divider
Connect the battery last.Check the LilyGo socket polarity against the battery connector, then connect the 3.7 V LiPo. Do not force a similar-looking plug. Power first by USB and check for shorts before relying on the battery.
Step 6 photo coming soonBattery connection and polarity check
Flash, configure, and calibrate.Flash the Nitrox firmware over USB, verify that the ADS1115 is detected, then calibrate in clean air at 20.9% O2. Pair a printer only after the measurement is stable.
Step 7 photo coming soonFirst boot and calibration
Close and verify.Close the housing with the specified M2 screws, compare readings with a trusted analyser or known gas, and verify a test label before taking the device diving.
This adapter is a listener on the Divesoft rear serial output. It must not backfeed the analyser and must be disconnected from the analyser while USB flashing. Before the first live test, enable Menu > Preferences > Send Data to USB > On on the analyser (sometimes called Data output).
1 × Waveshare ESP32-S3-Zero — bare board, without fitted pin headers or a housing
1 × male DVI connector with solder pins/pads
Short insulated hookup wires / cable
2 × M2.5 × 6 mm flat-head screws
1 × printed housing set — print it from the released file or order a printed housing when available
For older Divesoft Trimix analysers only: 1 × DS3231 Mini RTC module
Pinout at a glance
Divesoft TXD
Rear connector pin 4 → ESP32 GPIO4 RX, directly
Divesoft ground
Rear connector pin 14 or 15 → ESP32 GND
Optional analyser power
Rear connector pin 13 → ESP32 5 V
Optional print button
GPIO7 → momentary button → GND
Optional RTC
GPIO1 SDA, GPIO2 SCL, 3.3 V, and GND
Prepare the housing and connector.Print the released housing or order a printed set when available. Dry-fit the DVI connector and Waveshare board, then confirm the two M2.5 × 6 mm flat-head screws close the housing without touching the board.
Step 1 photo coming soonHousing, DVI connector, and board
Solder the receive-only data line.Connect Divesoft rear connector pin 4 directly to ESP32 GPIO4 RX. Do not put a single series resistor in this line for normal Divesoft 3.3 V TTL output.
Step 2 photo coming soonPin 4 to GPIO4 RX
Connect ground and optional switched power.Connect pin 14 or 15 to ESP32 GND. If the adapter is powered from the analyser, connect switched 5 V from pin 13 to ESP32 5 V. Measure the DVI pads before final assembly.
Step 3 photo coming soonGround and optional 5 V
Add only the needed options.The analyser pause gesture normally triggers printing, so GPIO7 button wiring is optional. Fit the DS3231 RTC only for older analysers that do not provide a clock; connect it to GPIO1 SDA, GPIO2 SCL, 3.3 V, and GND.
Step 4 photo coming soonOptional button and RTC
Flash with the analyser disconnected.Disconnect the adapter completely from Divesoft wiring, connect only the ESP32-S3-Zero by USB, and flash the Trimix Adapter firmware. This prevents USB power from backfeeding the analyser connector.
Step 5 photo coming soonSafe USB flashing setup
Enable data output, then test live data.On the analyser select Menu > Preferences > Send Data to USB > On; some versions call it Data output. The adapter cannot receive readings until this is enabled. The exact setting is in the official Divesoft He/O2 manual, section 12. Then close the housing, check live O2/He values, pair the printer, and compare the first labels with the Divesoft display.
Step 6 photo coming soonLive data and label verification