Calibration Notes

Written by Grace Lo

This is a WIP page with calibration notes that may be helpful.

From what I understand, the previous prototype read voltage readings from the Figaro NGM2611-E13 methane sensor and later post-processed the data for ppm readings.

The current setup provides methane data in raw analog values. I propose the code stays as is to maintain the highest level of precision and reduce computation during deployment, then the raw analog values can be post-processed using the following conversion sequence:

where

• V_C = V_IN = 5
• R_L = 1.1k-4.7kΩ
• PPM uses the graph from TGS 2611-E00