Table of Contents

Waspmote VOC's Sensor

Quick Data

Conversion Method

Converting to Concentration of CO in Air (parts per million)

The output of the waspmote to the database is a voltage reading, as can be seen from the circuit diagram below, this reading is affected by the input voltage, sensor resistance and load resistance.

To convert to ppm, the voltage reading is applied as follows

Step 1. Convert voltage reading to sensor resistance: Rsensor = Rload / ( Vcc - Vout) * Vout

Step 2. Normalise against resistance under air: Rsensor / Ro(Typical Resistance in Air)

Step 3. Compare normalised result against sensor response diagram:

Sensor Response Characteristics

Normalised Resistance (Rs/Ro) vs VOC's (ppm)
CO (ppm) = 10 (0.09721 - log(Rs/Ro)) / 0.6483

Example

Measurement of 0.9258v is observed (from our databases)

Notes

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