IDT Inline Flow Sensor
Content created by Bao Nguyen (outdated - sensor unstable for eDNA purpose)
Date: September 20th, 2019
We use this inline flow sensor to measure flow for eDNA. Flow is then translated to volume which is crucial for organism quantification with environmental DNA. We were looking at the FS1012 but this product requires external amplifier and analog-to-digital converter to effectively communicate with the Feather M0. Temperature compensation for ADC and amplifier also need to be considered. After amplifying the output, the sensor would required calibration with an industry-standard flow sensor. The output voltage is then mapped to flow rate for logging data.
For the time being and the hassle of calibrating the sensor, we have decided to go with the newer version of the sensor, FS2012. The FS2012 is factory calibrated, with I2C digital output. All we need to do is find a way to mount the sensor to the eDNA, and getting data back from it.
After reading the datasheet, the sensor works best at 5V while the I2C signal line to-and-from the Feather is only 3.3V. Here is where the Sparkfun Logic Level Converter comes to the rescue. This logic converter allows digital communication between a LOW and HIGH voltage system, in this case, is 5V and 3.3V. The pull up resistor for the I2C bus would only need to be on one side, either 3.3V line or 5V line but not both.
| Flow Sensor on eDNA |
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| Sparkfun Logic Level Converter |
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Code to communicate with the sensor, as well as PCB design can be found on the GitHub page.