The red board atop the Pi is the Pi Crust breakout board by Pumping Station: One member, Joe Walnes. It’s a compact and low-profile way to interface with the GPIO header. Alternatively, the Pi Cobbler breakout board is shown in the Adafruit tutorial. Note: the current Raspbian image doesn’t have the Adafruit’s PWM kernel module, so it is necessary to run Adafruit’s Occidentalis image for the servo tutorial to work.
Fellow hackerspace member, Jay Hopkins, had the great idea to wheel over the oscilloscope to demonstrate how the pulse width of the signal on the Pi’s PWM pin corresponds to the degree to which the servo rotates. (The spining red board on top of the servo motor is just a spare Pi Crust. It’s only function was to make it easier to see the servo was moving.)
The position of the servo motor is set by the length of a pulse. The servo expects to receive a pulse roughly every 20 milliseconds. If that pulse is high for 1 millisecond, then the servo angle will be zero, if it is 1.5 milliseconds, then it will be at its centre position and if it is 2 milliseconds it will be at 180 degrees.
Adafruit’s Raspberry Pi Lesson 8. Using a Servo Motor: This lesson describes how to control a single servo motor using Python. Servo motors are controlled by pulses of varying lengths. This requires fairly accurate timing. The Raspberry Pi has one pin that generates pulses in hardware, without having to rely on the operating system. Occidentalis includes an interface to make use of this pin for controlling a servo motor. (read more)
Adafruit has had paid day off for voting for our team for years, if you need help getting that going for your organization, let us know – we can share how and why we did this as well as the good results. Here are some resources for voting by mail, voting in person, and some NY resources for our NY based teams as well. If there are additional resources to add, please let us know – adafruit.com/vote
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.