Build guide
Recommended ESP32-S3 board, DVI pinout, safe wiring, flashing, and first test.
Open build guide
Trimix analyser readings to Niimbot labels
Trimix Analyser Connector
Big dives mean lots of cylinders to analyse, check, mark, and hand around. Handwritten tape can get messy fast, especially when everyone is prepping at once. This independent ESP32-S3-Zero adapter connects a Divesoft Trimix analyser to a supported Niimbot Bluetooth printer, so clear analysis labels come straight out of the workflow.
Nitrox-style labels are free. Helium and Trimix label printing is the optional Pro upgrade. Install the firmware now, then email the Device ID when you want to purchase a Pro licence code for your board.
Available now
Install the connector and print Nitrox labels for free.
The public firmware installer is open. Flash it to a supported ESP32-S3-Zero and use basic Nitrox label printing without a licence. To add helium values and Trimix labels, copy the 12-character Device ID from the local Web UI and email it to request Trimix Pro.
- No Arduino IDE, source build, or online checkout is required.
- The introductory Trimix Pro price is €79 lifetime, then €99 lifetime.
- Paste the supplied code into Activate existing key in the device Web UI.
Start with the free firmware
Install it now. When you want Trimix Pro, send the Device ID shown in the Licence section.
Open USB installer Request Trimix Pro by email Online card payment is not enabled yet.
Documented port
Uses the connector port documented by Divesoft; no opening or hacking the analyser.
Auto labels
Basic Nitrox labels are free; helium and Trimix label printing is Pro.
Date source
Uses the analyser time where available; Wi-Fi or an optional clock module can set the date on older setups.
Status LED
Clear colour states for WiFi, printing, countdown, and errors.
Board
ESP32-S3-Zero
Trimix Pro
€79 lifetime
Skill level
Basic soldering, no coding
Printer
Niimbot B1/B21
Never flash while connected to the analyser
Before flashing or updating the Trimix Analyser Connector, disconnect it completely from the Divesoft Trimix analyser. Flash only with USB connected to the ESP32-S3-Zero. Leaving the analyser wiring connected during flashing can backfeed or short signals and may destroy circuits in the adapter or analyser.
Before you expect live readings: enable analyser data output.
On the Divesoft analyser select Menu > Preferences > Send Data to USB > On. Some versions call this Data output. This is required even when the adapter powers on correctly. See the official Divesoft He/O2 manual, section 12 “Connecting to a computer”.
Simple external dongle
Plug in the dongle. No opening, no analyser modification.
The adapter is a small external dongle for the Divesoft Trimix analyser data port. Plug it into the documented connector and it listens to the analyser output while the analyser remains the source of truth for the measurement.
You do not need to open the analyser, solder inside it, or change its electronics. Make the external cable, plug in the adapter, pair it to the printer, and keep the original analyser workflow intact.
- Uses the existing analyser data port documented by Divesoft.
- The analyser display stays the check point before anything is printed.
- The adapter is removable, updateable, and independent from the analyser hardware.
- WiFi setup, printer pairing, owners, history, logs, and OTA stay in the Web UI.
One-button mobile printing
Press once and get a clean, readable cylinder label.
When the reading has been checked on the analyser, press the adapter button and the finished label is sent to the paired battery-powered Niimbot printer. No phone, laptop, or handwriting step has to be added while the team is already busy analysing cylinders.
The label is printed clearly for fast checking at the fill station or dive site: mix first, then MOD, END, date, and owner initials. No more decoding rushed handwriting or half-readable tape labels when several cylinders are being prepared at once.
- Single button press after the displayed values have been checked.
- Battery-powered mobile printer for bench, boat, van, or dive-site use.
- Trimix labels include oxygen, helium, MOD, END, date, and owner initials.
- Basic Nitrox label printing is available without the Trimix Pro upgrade.
Device Web UI
Set up WiFi, pair the printer, manage Pro, and check live readings.
The connector has its own local Web UI with the same blue theme as this site. Use it for printer setup, WiFi, owners, print history, label date/time source, OTA updates, diagnostics, and Trimix Pro activation.
- Copy the Device ID from the Licence page when requesting Pro.
- Signed entitlements remain offline-capable after setup.
- Live O2 and He values make it easy to verify what the adapter receives.
Shopping list
Parts for the Trimix Analyser Connector
We provide firmware and the installer. You source the electronics, make the Divesoft cable, flash the board from the website, pair your printer, and verify the first labels carefully. You do not need to compile code or install developer tools.
| Qty | Part | Purpose |
|---|---|---|
| 1 | ESP32-S3-Zero-compatible board (non-Waveshare recommended) | Main ESP32-S3 board with USB-C. In our testing, compatible non-Waveshare boards have been more reliable than Waveshare boards, so we recommend a non-Waveshare version. Buy the bare board without fitted pin headers and without a housing so it fits the printed enclosure. |
| Optional | Optional momentary push button | Optional manual print trigger; normally the analyser pause button triggers printing. |
| Optional | DS3231 Mini clock module | Optional clock module for older Divesoft analyser models that do not provide a usable date. |
| 1 | Short insulated hookup wires / cable | Connect the labelled data, ground, optional power, and optional button points. |
| 1 | Male DVI connector with solder pins/pads | Plugs into the analyser rear connector; solder the labelled connections shown in the diagram. |
| 1 | Printed housing set | Holds the ESP32 board, DVI connector, and optional print button. Download the print files on MakerWorld. |
| 2 | M2.5 × 6 mm flat-head screws | Close the printed housing. |
| Optional | Niimbot B1/B21 printer | Bluetooth label output. |
Tools
What you need on the bench
Soldering iron, multimeter, wire cutters, USB-C cable, printed housing, and two M2.5 × 6 mm flat-head screws.
Skill level
No coding experience required
Flash via the website, solder the DVI connector and button, pair the printer, then verify every printed label.
Build kits
Would you be interested in a build kit?
We are currently exploring offering build kits: the ESP32-S3-Zero board, DVI connector, optional print button, wiring, printed housing, and two M2.5 × 6 mm flat-head screws in one package, so you only solder and assemble. Before we commit to kits, we would like to hear your feedback first.
- This is research only; nothing is for sale here and there is no commitment.
- Tell us what a kit should include and what it would be worth to you.
- Email is optional and only used if you want to be contacted about kits.
Assembly and soldering
Trimix Analyser Connector pinout
Follow the labelled connections below. Before testing, enable Menu > Preferences > Send Data to USB > On on the analyser. Disconnect the adapter from the analyser before every USB flash or update.
| Connection | ESP32-S3-Zero pin | What to solder |
|---|---|---|
| Divesoft pin 4 | GPIO4 | Solder Divesoft rear connector pin 4 directly to ESP32 GPIO4. |
| Divesoft GND | GND | Divesoft rear connector pin 14 or 15 to ESP32 ground. |
| Divesoft 5V | 5V | Optional power from rear connector pin 13, switched by the analyser power state. |
| Optional print button | GPIO7 and GND | Optional push button for printing. Normally, pausing the Divesoft analyser triggers the label. |
- Required for live readings: enable
Menu > Preferences > Send Data to USB > On(or Data output). See the official Divesoft He/O2 manual, section 12. - Solder only the connections shown in the diagram.
- Measure the DVI solder-pad pins before final assembly.
Wiring diagram
Solder the labelled adapter connections.
Connect data, ground, and optional power exactly as shown. Unplug the adapter from the analyser before every USB flash or update.
Printed housing
Printed enclosure for the adapter.
Fit the electronics and close the housing with two M2.5 × 6 mm flat-head screws.
Download print files on MakerWorld- Prepare the cable. Use Divesoft pin 4 for data, pin 14 or 15 for ground, and optional pin 13 for power.
- Solder the data wire. Connect Divesoft pin 4 directly to ESP32 GPIO4, exactly as shown in the diagram.
- Solder the remaining wires. Connect ground and optional power. Add the optional print button or clock module only if needed.
- Flash the firmware. Disconnect the adapter completely from the Divesoft Trimix analyser before flashing. Then connect only the ESP32-S3-Zero by USB, open the installer in desktop Chrome or Edge, and choose full install for a new board. After flashing, unplug and reconnect USB power if the setup WiFi does not appear within 30 seconds.
- Enable analyser data output. On the Divesoft analyser select Menu > Preferences > Send Data to USB > On. Some versions call it Data output. Without this, the adapter can power up but show no live readings. See the official Divesoft He/O2 manual, section 12.
- Set up and test. Connect WiFi, pair the Niimbot printer, check live readings, and verify printed labels against the Divesoft display.
Cost before you install
Nitrox labels are basic. Trimix labels are Pro.
We do not sell the Divesoft analyser, ESP32 board, cable, printer, or finished adapter. You source and build the hardware. Basic Nitrox labels are free; Trimix label printing is the optional Pro upgrade. Install and try the basic workflow first, then email the Device ID from the adapter Web UI when you want to purchase Pro.
Trimix Pro pricing
€79 lifetime
Introductory launch price for the first month, then €99 lifetime.
End price for German consumers. No VAT shown under §19 UStG; no shipping costs for digital delivery.
No subscription. Helium/Trimix label printing, MOD/END output, and offline-capable signed activation.
How do you purchase?
Email the 12-character Device ID from the adapter Web UI to hello@trimixanalyser.com. I will arrange payment directly and send the matching activation code. Stripe checkout is not enabled yet.
USB flashing
Install from your browser now
Use update-only for existing devices so settings and the licence stay intact. Use full install for a new board, recovery, or when support asks you to use it. Firmware installation is available now and does not require a payment step.
- Use desktop Chrome or Edge.
- Disconnect the adapter completely from the Divesoft Trimix analyser.
- Connect only the ESP32-S3-Zero to the computer by USB.
- If it does not appear, disconnect USB, hold BOOT while reconnecting USB, then release BOOT and retry.
- Select Trimix Analyser Connector and the install mode.
- After flashing, unplug and reconnect USB power if the setup Wi-Fi does not appear.
- Open the adapter Web UI and email its Device ID when you want Trimix Pro.
Detailed documentation
Build, connect, print, and troubleshoot.
Simple HTML guides cover building, setup, printing, and common problems.
Online manual
English, German, and Dutch setup and operating instructions.
Open HTML manualDivesoft data output
Required menu setting, labelled wiring, and no-reading checks.
Open data-output guideTrimix cylinder labels
Niimbot setup, pause-to-print, label fields, repeat protection, and verification.
Open label guideTroubleshooting
Analyser data, Wi-Fi, LED, printer, licence, and update faults.
Open troubleshootingDownloadable BOM
A spreadsheet-ready CSV with the recommended board, connector, housing, options, and printer.
Download Trimix BOMBuilt from technical and cave-diving experience
A practical answer to complex gas logistics.
Dr. Clemens Chaskel built the connector around the needs of long-duration cave dives, dives deeper than 100 metres, mixed teams, and multi-cylinder gas logistics—while keeping the Divesoft analyser as the source of truth.
Field-led engineering
More than 30 years of diving experience, GUE Cave 2, CCR 2+, and Tech 2+ qualifications, and a Chartered Engineer's approach shape the connector and its verification workflow.
About Dr. Clemens ChaskelImportant safety note
The adapter copies readings from the Divesoft analyser and prints them. It does not make the gas analysis safer by itself. Always verify the analyser display, gas mix, date, MOD/END, and printed label before diving.