Test board partial success

A project log for VISP - Ventilator Inline Sensor Package

Bidirectional flow (volume), pressure, and temperature sensing in a single inexpensive I2C/SPI package.

Daren SchwenkeDaren Schwenke 04/10/2020 at 06:370 Comments

The boards arrived from OSHPark yesterday and @Steven.Carr  got right to work populating them for reflow.
He ran into some issues.

Our placement for the pads to allow either the BMP280/BME280 or BMP388 sensor to live on them was problematic and resulted in failure to properly reflow without the case shorting to one of the adjacent pads/lines.
They are too close together.

Steven eventually was able to salvage a few for testing through some careful rework so this is not a total loss though.
The good news is the xlator is doing its job, and we have two sensors which are working in the right configuration now to move forward.

This will enable us to test a few different pitot tube configurations to determine the ideal gain/flow tradeoff.  Bigger tubes give us more gain, but this will also increase the restriction through the pickup reducing our overall flow.

I'll be modeling a range of pitot tube sizes for him to try out.  We will still need some form of calibrated flow to compare these though.  We'll have to work on that.  Worst case a garbage bag full of air would give us a calibrated volume from which we could extrapolate the flow, but that wouldn't give us very much to work with.  We'll need something better.