Building a Lego-powered Submarine 4.0 - automatic depth control

This radio-controlled submarine can maintain a steady depth or a certain distance from the bottom. It is equipped with a pressure sensor and a laser distance sensor. Raspberry Pi and PID control are used for automation. Tested in a swimming pool and a small river (at the end of the video). Enjoy! 0:00 building 2:36 tests in water 3:48 long journey in a small river 6:47 full Python code SPECS Displacement: 2.4 kg (5.3 lb) Test depth: 1.5 m (5 ft) Hull: acrylic plastic cylinder (250x110x3mm), SAN plastic lid (2mm thick) Lid seal: o-ring 2.5 mm (NBR 70 shore) Ballast tank: 60 ml syringe (Eotia marinade injector), Lego EV3 Medium Servo motor (45503) Forward propeller: drone propeller (Diatone Bull Nose 4x4.5), Lego PF L-motor (88003) Turn propeller: Lego propeller 3 blade (6041), Lego PF M-motor (8883) Magnetic couplings: K&J Magnetics D38-N52 neodymium magnet, TapeCase 423-5 UHMW Tape, silicon spray Motor driver: 2x Pololu 2130 DRV8833 Dual H-bridge Radio control: 27 MHz controller dissembled from a toy submarine (no-name chinese Mini U Boat) Pressure sensor: Honeywell SSCMANV030PA2A3 2 bar Laser distance sensor: SparkFun TFMini-S Micro Computer: Raspberry Pi Zero 2 W Power supply: Lego Rechargeable Battery Box 9V (8878), Pololu 2123 S7V8F5 5V voltage regulator MORE DETAILS CODE #cHnVI6NjaPkfZcdZvFZZ0Q or PREVIOUS SUBS 1.0 syringe ballast 2.0 magnetic couplings 3.0 balloon and compressor MUSIC Tommy Baynen - Stone Paths