YTCam includes a Raspberry Pi3A+ single board computer (SBC) equipped with a “Global System for Mobiles” (GSM) modem, global navigation satellite system (GNSS aka GPS) receiver, PiCam V2.1 and WiFi access point housed in a thick wall PVC tube assembly. YTCam is a waterproof, sealed unit, with a power cable to be connected to the 12V power supply of the boat. It measures approx 170-200mm high and 90mm diameter.
The SBC component is based around a Raspberry Pi 3A+ which offers a low cost and rapid route to producing a flexible prototype. The Pi 3A+ includes hardware for the provision of the WiFi access point which will be used for configuration and management. In addition to the Pi 3A+ we have designed a Pi “hat” printed circuit board (PCB) which plugs directly into the main header and includes the other components of the system (GSM modem and GNSS receiver) as well as a small uninterruptible power supply, fuse and power conditioning systems. The PCB uses a SIMCOM 7600E modem that provides the GSM and GNSS requirements via appropriate level-shifitng and power provision. An integral uninterruptible power supply (UPS) uses a bank of “super capacitors” to provide approximately 60s of runtime after power disconnection to allow a clean shutdown of the system when it is unplugged. This assists with long term reliability as it reduces the likelihood of filesystem corruption and other operating system related problems. The UPS has a significant in-rush current requirement (~5A @12V for ~500ms) upon start-up due to the need to rapidly charge the super capacitors, this current is limited using a series resistor and rapidly reduces after the first second of connection. The continuous current requirement after initial power-up will reduce to less than 1A after 1 minute. The SBC/PCB assembly is mounted in a 3D printed retainer to prevent movement inside the main housing tube and the antennae for the GSM and WiFi are housed internal to the main housing to reduce the risk of damage. The camera is mounted in the bottom of the case behind an acrylic window.