A SEABED SONAR THAT LOGS ON ITS OWN FOR MONTHS — THE LOGGER, HOUSING AND BATTERIES COST 1,700 EUR
A battery-powered scanning sonar that sits on the seabed for months, with a homemade logger, housing and battery pack for 1,700 EUR.
by Frederik-Willem Fourie and colleagues
ScienceOpen-hardware
Built withArduinoRaspberry Pi3D printing
- difficulty
- ●●●●●
- time
- several weekends
- license
- CC-BY-4.0
- repo
- repo FINISHED0 stars
●●●●● · several weekends · CC-BY-4.0 · 0 stars · repo FINISHED
WHAT YOU’LL NEED
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COMPAREE VERDICT
This is a specialised build for marine researchers who need long-term acoustic imaging of the seabed without a commercial logging stack such as the Imagenex 881A plus ASL IRIS logger. The Sonarlogger pairs a purchased Echologger RS900 scanning sonar (about 11,550 EUR) with a homemade logger, battery pack and underwater housing that together cost about 1,700 EUR, bringing the whole system to 13,250 EUR. The logger is a Raspberry Pi Zero W for sonar control and Wi-Fi download, with an Arduino Pro Mini power controller that sleeps the system between scans. The housing is a POM cylinder with double O-ring endcaps, designed for 500 m on paper but only proven in water shallower than 30 m, and the battery pack is a 3D-printed cage of alkaline D-cells you can reconfigure. It logged for about 138 days across several deployments in the Belgian North Sea, the longest 57 days, scanning every four hours. The hardest part is not the electronics — the PCBs and code are on OSF — it is getting the housing machined and sealed (or buying a commercial housing, which the paper mentions as the pricier alternative) and planning safe mooring and recovery. If you are running a seabed monitoring program, this is a well-documented starting point.
IN THE REPO
GOOD TO KNOW
- —Full bill of materials with suppliers in the HardwareX paper and on OSF; about 1,700 EUR for logger, enclosure and battery pack, excluding the commercial sonar head.
- —CAD files for the enclosure and battery pack, the custom PCBs and the Raspberry Pi and Arduino code for the logger are on OSF.
- —Detailed assembly instructions, power budget calculations, and field deployment procedure are in the paper.
- —The Echologger RS900 sonar head itself is commercial (about 11,550 EUR) — this project is the logger, battery pack and housing around it.
- —Licence is CC BY 4.0, permits commercial use with attribution.
- —No GitHub repository; all files are hosted on OSF (Open Science Framework).
Parts to buy
8 itemsFrom our check of the build. Exact quantities and part numbers are in the creator’s BOM.
Can I build this?
Build at your own risk. Projects involve tools, electronics and sometimes mains voltage — follow the creator’s safety notes.
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Start here
Navigation into the creator’s own docs — we don’t rewrite the guide, we route you to the source.
- 1.Read the HardwareX paper end to end (It contains the full build rationale, design decisions, and field test results — treat this as the manual.)
- 2.Download all files from OSF (CAD for the housing, PCB files for the logger, firmware, and the bill of materials spreadsheet are all there.)
- 3.Source the Echologger RS900 sonar head(This is the single largest cost item and the one commercial part you cannot substitute — confirm availability and lead time before ordering anything else.)
- 4.Machine or commission the pressure housing(The housing design is in the CAD files, but you need a lathe or a machine shop to make it — or budget for a commercial housing instead, which the paper mentions as the pricier alternative.)
KNOWN ISSUES
- The housing must be pressure-tested before any deployment — a leak will kill the electronics and possibly lose the instrument. The 500 m figure is a design value backed only by simulation; the authors note it still needs physical pressure testing, and all their field tests were in less than 30 m of water.
- The logger is built around the Echologger RS900 interface and power draw (6 W) — do not assume another scanning sonar is a drop-in replacement; check its serial protocol and power requirement first.
- Battery pack sizing depends on your scan schedule and deployment length; the paper gives a power budget but you must calculate your own. Overestimate capacity or plan for an early recovery to swap batteries.
- The two underwater bulkhead connectors (Dwtek MCBH micro-circular) cost about 150 EUR each in the paper's BOM and sit in drilled and tapped holes in the endcap — that seal matters as much as the O-rings, so take care when fitting them.
- Wi-Fi download works line-of-sight on deck but not underwater — you recover the instrument to pull data, so plan your deployment around the recovery logistics, not the idea of remote access.
- Field deployment needs a mooring frame, anchor weight, and recovery line with flotation; the paper shows the setup but assumes you know how to rig and deploy subsea moorings safely.
Can I use a different sonar head?
Possibly, but the logger software is written for the Echologger RS900 serial interface and power requirement. A different head means rewriting the communication code and possibly the power supply — treat it as a fork, not a swap.
How long does the battery last?
That depends on your scan interval and battery chemistry. The paper estimates about 130 days with alkaline D-cells and one scan every four hours; Table 9 in the paper shows how lithium or NiMH packs and other intervals change that.
Do I need a boat to deploy this?
Yes, unless you are deploying in very shallow water from shore. The mooring frame, weight, and recovery line make this a small-boat or dive-team job, not something you throw off a dock.
What if I do not have a lathe?
Then find a machine shop willing to fabricate the housing to the OSF CAD files, partner with a university or institute that has the equipment, or buy a commercial housing — the paper mentions off-the-shelf options from Nortek and BlueRobotics, though they cost more or have a smaller inner diameter than the custom design.
Is the logger waterproof or just the housing?
The waterproofing is the housing: a POM cylinder with double O-ring seals on both endcaps. The electronics inside are not described as separately protected, so if the housing leaks, assume everything inside is lost.
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Discussion1
FROM THE COMPAREE TEAM
About 1,700 euros for the logger, housing and battery — the sonar itself is the big cost, at 13,250 euros for the full system. The paper rates endurance at 130 days on 4-hour scans. If you were deploying this, what scan interval would you actually set?
Frederik-Willem Fourie and colleagues
Built at the Flanders Marine Institute (VLIZ) to watch bivalve reefs change over time in turbid coastal water, where vessel surveys and cameras fall short and commercial sonar loggers are expensive. Tested in the Belgian North Sea over several deployments totalling about 138 days.
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- Information is provided without warranty and may become outdated as projects evolve. Prices are indicative bands only — always check the creator’s parts list for current costs.
- Building and operating any project is at your own responsibility. Protective equipment, safe workshop practice and compliance with local regulations are the builder’s responsibility.
CompareeTEAM27d agoedited
Practical notes from our verification: this is not a GitHub project — it is a HardwareX paper (CC BY 4.0) with design files on OSF (doi 10.17605/OSF.IO/4GTZ8), so the documentation reads like a journal article rather than a repository. The OSF files include mechanical drawings and CAD for the housing (STEP, PDF and SolidWorks), schematics and PCB files, and the paper walks through assembly. The electronics are a Raspberry Pi Zero W with an ATmega328p handling power management, driving an Echologger RS900 scanning sonar, all in a POM housing designed for 500 m and powered by an industrial alkaline D-cell pack. Data comes off by Wi-Fi after recovery: the Wi-Fi mode is off by default to save power and is switched on with a magnetic reed switch, so this is a deploy-and-recover instrument, not a live feed. In field tests in the Belgian North Sea in 2021 and 2022 it logged around 138 days in total across five deployments, the longest 57 days, at 4-hour scan intervals. Correction (4 October 2026): we re-checked this page line by line against the project's own repository, documentation and videos, and fixed errors in earlier versions.