Raspberry Pi-based水下相机

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The Unboxed STEM Club consists of three friends aged 10 to 13 who meet up each weekend with two dads. Pinak, Vihaan, Yuvan, and their mentors Kshitij Varma and Dr […] The Unboxed STEM Club consists of three friends aged 10 to 13 who meet up each weekend with two dads. Pinak, Vihaan, Yuvan, and their mentors Kshitij Varma and Dr Amol Patil, noticed that people talk about protecting oceans and rivers, but rarely have the tools to measure what’s happening below the surface. Sensea was conceived as “a low-cost DIY (£130) underwater explorer that would reveal what’s going on below the surface of our local ponds and rivers”, proving that you don’t need expensive equipment to investigate the depths. The boys built a custom camera rig, based around Raspberry Pi 3 Model B+ . Not only was this solution more affordable, but it also had the advantage of low power consumption, running off a standard 5V USB power pack for longer. The most important aspect of all was how to keep the electronics dry. The container needed to be completely waterproof at all times while still allowing the sensors to measure the surrounding water and the camera to see clearly. It also needed to be opened and resealed to insert delicate sensors and rechargeable batteries, which made for quite the engineering challenge. The team designed a sealed acrylic tube that acts as a transparent pressure chamber, keeping the electronics dry while allowing the camera to see through its end cap. One end is permanently sealed with a 10.5cm acrylic disc bonded using marine epoxy. A waterproof cable gland is drilled through this end, allowing the DS18B20 temperature probe cable to pass through while maintaining a watertight seal. At the other end is an expanding drain plug of the sort used by plumbers to check for leaks. The setup proved reliable and, crucially, dependably waterproof. Nonetheless, Sensea’s makers implemented a leak test regime that sees the fully sealed Sensea tube and cable submerged in a bucket of water for five minutes, to check for rising bubbles. Once this critical test is complete, the tube is lowered into the water in its protective cage. Getting the buoyancy and descent right was another challenge. A 2kg bone-shaped dumbbell, selected after many experiments with size and weight, ensures the Sensea sinks beneath the river surface, ready to start recording what its Raspberry Pi Camera Module 3 can see. The Camera Module captures 10-second underwater video clips and logs time-stamped water temperature readings from a waterproof DS18B20 sensor. The team settled on a manual fixed focus, since autofocus was likely to struggle when encountering suspended particles in the river. “Fixing the focus gives much sharper and more stable footage,” they explain. The setup also includes a PCF8523 real-time clock that records accurate time stamps even without an internet connection. Video capture is triggered via a Python script called sensea_logger.py , which also measures the water temperature and ensures everything is written to Raspberry Pi’s microSD card for post-submersion retrieval. For their initial deployments, the team compared temperature measurements from the River Cam and a nearby lake called Todd’s Pit, clearly revealing differences between the two environments. Future additions may include a pH sensor for pollution monitoring, a depth or pressure sensor, and even AI-powered species identification. Tags: Raspberry Pi Add us as preferred source Share Tweet Share Pin Previous Post Scalable high-density 2A LXI matrix for changing test requirements Next Post Versatile EdgeCortix chiplet for physical AI David Manners David Manners has more than forty-years experience writing about the electronics industry, its major trends and leading players. As well as writing business, components and research news, he is the author of the site's most popular blog, Mannerisms. This features series of posts such as Fables, Markets, Shenanigans, and Memory Lanes, acr