What is it?

This is an appallingly small add-on board with two push buttons and three leds all connected to a common ground that can be soldered directly to a Teensy 3.X or used on a breadboard to provide actuation and indication for any project. The leds are arranged in a stop light pattern with red, yellow and green from top to bottom, respectively. I have made an attempt to reduce and equalize the brightness of the three leds by using different resistor values from 1 K to 4K7. This limits the current required to just a few mA and keeps the led light, which can be very bright at 20 mA, easy on the eyes. The board GND can be connected either to the Teensy (or other microcontroller) ground or by using digitalWrite(LOW) to any GPIO pin. Then to actuate the leds, just use digitalWrite(HIGH) to supply 3V3 to the respective pins. For the buttons, set pinMode(PULLUP) on the button pin and use the Teensy debounce library to detect when the button press pulls the pin down to GND through the 10 K on-board resistor. The buttons can be programmed to actuate subsequent Teensy actions, including lighting one or more of the on-board leds.

Why did you make it?

There are a lot of uses for led indication and button actuation from turning on a circuit to indicating when the Teensy receives an interrupt from a sensor, etc. The pin 13 led on the Teensy board is useful for this in many cases but there is only one and this led is often unusable since pin 13 is typically used as the CLK signal for SPI on the Teensy 3.X. This small board provides a means for users to interact with their projects initiating action through the buttons and seeing the results through the led indication.

What makes it special?

This is an appallingly small add-on board that fits in almost any Teensy project. It is useful on the breadboard and can be used with other microcontrollers like an Arduino Pro Mini too. Order the board from OSH Park and make your own or order a fully assembled and tested Button & Lights board from me and see how easy it is to add buttons and led indicators to your project!