Flow sensor connector-cable combinations for proximal ventilation of newborns and premature infants
So that left or right does not become a fateful question.
Accordingly, NICOLAY assumed responsibility for the development of a flow-sensor solution with a number of variants as an adaptation to the Sensirion flow sensors. In the process, the different variants and cable outlets needed to be taken into account. The development project also included a circuit board with suitable hardware for communicating with the Sensirion sensors and evaluating the signals, which are then transmitted via a serial interface. In addition, the project included the creation of the necessary documents, such as a communication protocol for implementation, as well as software.
The cable outlet in the cap needed to lead both to the left and to the right in order to guide the cable away from the patient during operation, depending on the use of the sensors. Since the sensor is often used proximally, it is very close to the patient and thus the cable must not get in the way.
NICOLAY needed to select a suitable spring contact strip with sufficient spring deflection to ensure a secure contact when adapting it to the Sensirion connector. In doing so, all of the tolerances along the entire chain had to be taken into account when it came to the assembly of the individual parts – from the Sensirion sensor’s printed circuit board and its assembly to the mounting components and the soft overmoulding. Even the tolerances of the cover and housing have to match in order to prevent the potting from leaking without additional sealing processes.
The circuit board in the flow sensor connector must be protected against influences such as vibration; the cover and housing require a robust connection.
For the development of a cable, NICOLAY had to take the requirements of the RS232 and RS485 serial interfaces as well as the possibility of looping through the six contacts without a circuit board into account in order to establish direct I²C bus communication. The necessary cross-sections for the communication and supply cables also had to be considered.
Printed circuit board and software development
In order to process and convert the signals from the Sensirion sensor, the design, layout and function of the circuit board had to be achieved in the smallest possible space. When it came to programming the microcontroller, Sensirion’s specifications and the EMC requirements had to be taken into account. The software was needed display the data on a PC. In addition, there was a simulation variant for customers to display the gas flow and a variant that served as a development environment for optional adjustments via bootloader and to evaluate the data and commands.