Goal

The goal of this project was to provide a much needed update to legacy CO2 monitoring systems.

Method

For this update we planned to replace the LI820 (old) sensors with the new LI830 sensors. The challenge was that these sensors communicated using xml commands and these tags were changed for the new sensor. As we could not edit the firmware on the original cardstack we decided to create a UARt serial bridge that would translate the commands from the cardstack to that understood by the sensor.

Work Done

• Developed the firmware using Interrupts and branching logic.
• Designed the PCB prototype using KiCAD.
• Was responsible for the component selection and communicating with the PCB manufactures.
• Tested the bench-top circuit and the prototype of the serial bridge.

Challenges

The timing constraints of the cardstack were very harsh. This caused problems as there was a delay generated by the UART bridge which was causing the cardstack to neglec the data. To overcome this challenge I overclocked the MSP430 to 24MHz which minimized the delay.