Pinouts

pIRKey is pretty simple so you don't actually have a lot of pinout requirements!

USB Connector

On the left is a PCB-mount USB connector, just plug it right into any USB-A port. the 4 gold plated pads have Ground, D+, D- and 5V power. The 5V power is regulated down and used to power the pIRKey. The D+/D- is what the onboard chip uses to send/receive data

Microcontroller

The chip used here is the ATSAMD21E18 - the same chip in our Trinket M0 and Gemma M0. It has 256KB of flash, 32 KB of RAM and runs at 48MHz. We pre-load CircuitPython but you could also use Arduino if you like, just select Trinket M0 as the board type.

Reset Button

You can reset the board or put it into bootloader mode using the Reset button. One click resets. Double-click puts into bootloader mode. In bootloader mode, the small DotStar LED will turn green on successful USB enumeration, or red on failure

DotStar LED

We put a small RGB LED on board. This is great for helping the user know if the IR command was read properly, what the status is, or changing modes.

In CircuitPython you can communicate with the DotStar over the board.APA102_MOSI and board.APA102_SCK pins

Infrared Receiver

At the end is a lensed IR receiver module, it will read IR light, amplify if necessary and filter out the 38 KHz sub-carrier so you just get pulses when light is detected, making it a lot easier on the pIRkey!

Note that even though it is tuned to 38 KHz, you can use about 30 KHz to 46 KHz without too much difficulty, its not a very precise filter on purpose since low cost IR remotes have a lot of drift.

In CircuitPython you can read data over the board.REMOTEIN pin

This guide was first published on May 23, 2018. It was last updated on May 23, 2018.
This page (Pinouts) was last updated on Jul 30, 2020.