This example will show you how to monitor both USB and VIN power source, query values and raise visual and hardware alerts in less then 5 minutes.
The USB power source will power your Nano host board (5 volts) and VIN MON will power your peripherals (12 volts). For convenience we will mount it on a breadboard but this is not mandatory.
USB minimum voltage and VIN maximum current will also trigger a hardware alert if breached.
We defined a current limit of 1A on VIN. Now let say we connect a dummy load of 8 Ohms only. Here is the result:
The 12 V power source is connected to the VIN MON pin (red cable at the bottom right) The dummy load is connected to the VAUX pin (red cable at the top right) The OLED shows the alert screen VIN_I means there is a fault on the Vin current. Underneath is the value of 1117 mA.
The “VIN Alert” test point is normally at 4.2 volts. In this case the hardware error is raised and the voltage at VIN Alert TP is 0 V.
All other alerts will show quite the same screen. For example in case of a voltage of 3.00 V on the USB (the limit is set to 4.5 V), the oled will display
If you open the serial monitor you will get this