Hardware

Different hardware components can be used, depending on the chosen mode of operation. The selection provided below is thereby based on our default PCB layout. This uses the Adafruit Feather M0 form factor (53.65 x 23 x 8 mm).

FreiStat-USB

The serial USB mode is the classical way of operation for laboratory or short distance setups.

Required Components:

• Adafruit Feather M0 microcontroller (e.g., Adafruit Feather M0 Basic, Adafruit Feather M0 WiFi, Adafruit Feather M0 Bluefruit LE)
• AD5940 PCB

FreiStat-WiFi

The WiFi mode allows for long distance setups, by using UDP connection to transmit the data to a specified IP and port.

Required Components:

• Adafruit Feather M0 WiFi microcontroller
• AD5940 PCB
• SD-Card reader

FreiStat-Standalone

The Standalone mode uses an OLED-display in combination with the default values on the microcontroller to execute measurements, without requiring a computer. The data is directly stored as .csv-file on the SD-card.

Required Components:

• Adafruit Feather M0 microcontroller (see FreiStat-USB)
• AD5940 PCB
• SD-Card extension
• OLED display

Pin Interface

The pins of the AD5941 are connected like described below:

• AD5941 GPIO0 connected to A1 (Interrupt Pin)
• AD5941 GPIO1 connected to A2
• AD5941 GPIO2 connected to A3
• AD5941 Reset connected to A4
• SPI (CS line connected to A5)