Paul Voss, a Professor from Smith College and an inventive engineer, has two interesting applications using the Propeller 1. The first is a timely test fixture he made for the MITMedia Labs MASK Project: N95 Alternative Face Mask project. The second is something we’d all like to have when the COVID-19 pandemic has eased – the SpecCNC AeroForm Complete CNC Hotwire Foamcutter.
Propeller 1 Test Fixture for the MASKproject: N95 Alternative
The MIT Media Lab MASKproject was formed by a group of inspired engineers who are setting out to save more lives by making an alternative N95 face mask. Their goal is to make a reusable face mask which is mass manufacturable with rapid deployment, open hardware, sterilizable, modular, and filter-media agnostic that aims to hit the N95 efficacy criteria.
Parallax customer and Smith College Professor Paul Voss is a contributor to the project with a test fixture, based on the Propeller 1 Multicore Microcontroller. His test rig measures respirator filter performance (flow, resistance, particle penetration). Paul indicates that the project is moving fast with prototype injection-molded parts already coming off the line. His text fixture accepts filters into this cardboard/plywood structure where measurements are taken during air movement through the filters (which are embedded in a PVC tube from the hardware store).
I asked Paul about how he produced the circuit board so quickly. The circuit board was actually created for his Aerial Design Course at Smith College and it uses a Propeller 1, Analog Devices 16-bit 6-channel A/D, two Freescale pressure sensors, 3.3 and 5V reference voltages, and numerous pins for servos, LCD, Ping))) Ultrasonic Sensor and a 9 degree-of-freedom gyroscope/accelerometer/magnetometer. The project was coded in Spin and the circuit board was quickly adapted as the test fixture for MASKproject.
The values shown on the LCD are:
- PA = Ambient pressure [Pa]
- DP = Differential pressure across filter material in the test section [Pa]
- HT = Height of variable-volume tube measured by Parallax Ping))) [mm]
- DH = Change in height over five-second period [mm]
- QT = Volumetric flow rate through the filter test section [LPM=liters per minute]
- VT = Velocity of air through the test section [mm/sec]
- QM = Volumetric flow rate through the prototype respirator assuming same velocity [LPM]
The efforts of Matt Carney, Paul Voss and the MASKproject team are incredible and recognized!