Figure 1 shows the back side of Version 3.0 of the Op-Vent printed circuit board. Press the button above to download Gerbers and KiCAD source files for this board. To support oxygen blending, this board supports up to three Honeywell I2C flow-meters, has two proportional and one on-off relay driver, and has two high-pressure (0-30PSI)sensors to monitor both air and oxygen input pressure. An analog switch selects between the flow meters, so they can all share the same I2C addres.
Inherited from Version 2.5, this version also has an ATMega1284p microcontroller, a 10kPa pressure sensor (and sites for three more low-pressure sensors), a 110dB alarm, two encoder/push-buttons, three LEDs, an I2C interface to connect to an LCD display, dual RS232 interfaces, a battery backup circuit, and an alarm relay. On this board the RS232, battery backup, and alarm relay are not populated. The USB interface is dropped from Version 2.5 to make room for the additional flow meter connectors.
Figure 2 shows the front side of the PCB mounted in the prototype. This side of the board mounts the two shaft encoder/pushbuttons, the 12V power connector, the three LEDs, and the alarm. The alarm is not populated on this unit. (The alarm mounts in the white circle at the bottom of the board).
Figure 3 and Figure 4 show the back and front of Version 2.5 of the PCB. This version is used in many single-gas versions of OP-Vent. It supports only a single Honeywell I2C flow meter. It does include a USB interface (not in Version 3.0) that is not populated on this particular board. The front side shows the alarm that is missing in Figure 2. Press the button above to download the Gerbers and KiCAD source files for Version 2.5.