The enclosure dimensions are 4″X4″X2″, LXWXH. This allows enough room for one small arduino board, a 9 volt battery, 1 small HMI, 1 Pulse Sensor, and one on/off switch. The enclosure door is completely removable and allows easy access to the arduino board. A large polymer gasket is sandwiched between the enclosure door and enclosure body and is fastened with 4 heavy duty screws . This allows the Pulse Meter V2 to work under harsh/wet environments., Another view of the Pulse meter while it was under construction. There was definitely some space issues but the components found their way in without interfering with each other. The enclosure door was machined to high tolerances using a CNC mill. A sheet of plexiglass was adhered to the enclosure door on top of the HMI, and pulse sensor to create a transparent, water-tight seal.,