Last time, I talked about how a bidirectional MOSFET level shifter works and how to design (and test) one. Now, let's talk about a simple application where one would be very nice to have; I'll even show off a simple design I made.

Let's talk Raspberry Pi. Nice little board. Has lovely 3.3V signals. Can source and sink nearly no current, and its pins are very easy to burn out. It's very much the opposite of our usual Microchip PIC microcontroller, which costs about 1/50 the price and is much more tolerant of wide voltage ranges. A Raspberry Pi is lovely to use as the 'big brain' to your project, and a PIC is great to use as the immediate interface to all your sensors, and so on. By doing this separation of concerns, you can much more easily bring up all your sensors, create an entire separate PCB for your sensors and microcontroller, and then simply use the microcontroller to gather data, control peripherals, send data to the Raspberry Pi, and receive instructions back. After the jump, I'll explain the setup.