Build a walking piano with the RaspberrySTEM Creator Kit

Brian Silverman was looking for a way to teach his kids electronics, so he decided to create a kit, complete with projects featuring step-by-step instructions, all the electronic materials needed to complete the build, and Python code to bring the projects alive. In summer 2015, after two years of development and testing, Silverman and his friend Jason Steinhorn released the RaspberrySTEM Creator Kit [1].

Assembly

The kit comes neatly packaged in an 8.5 x 5.25 x 4.25-inch (~12.5 x 13 x 11cm) box with a Raspberry Pi 2 (RPi2), components for building a case, cables and adapters, project electronics, and a microSD card with the RaspberrySTEM Development Environment (RDE) preloaded (Figure 1). The Assembly Guide explains how to build the kit simply and clearly with accompanying illustrations. My kit went together easily, without a problem – no missing, mystery, or malfitting parts (Figure 2). All in all, it took about 20-30 minutes to a fully functional kit ready to be plugged in.

Figure 1: The RaspberrySTEM kit unveiled. On the left are the acrylic pieces for the case. Other components are grouped together logically and boxed separately: top right are the "cells" (project hardware); bottom right are the parts needed for assembly. In the center are the RPi2, an AC power supply, a pre-loaded microSD, and the Assembly Guide.

Figure 2: The RPi2 installed in a partially built case. The Phillips head screwdriver was all I needed for the entire assembly.

When assembled, the kit simplifies the RPi2 interface down to a connector board attached to the RPi2 GPIO pins, a small speaker, and a full-sized breadboard. Power, HDMI, and audio ports are accessible through openings in one of the acrylic side panels. One open side of the case allows uninhibited access to the USB and Ethernet ports, and the other open side leaves the microSD slot accessible (Figure 3). The top part of the case is called a "lid," which implies that other lids are planned down the road for new sets of projects.

Figure 3: A fully assembled RaspberrySTEM. The speaker is already plugged in to the audio port.

The final step is to plug in all the peripherals, slot in the microSD card, and provide power. On bootup, the operating system briefly shows the Raspbian desktop before bringing up the RDE (Figure 4). If you want to return to Raspbian (7.8 wheezy), just enter Ctrl+Alt+D; then, click on the RaspberrySTEM tab to return to the RDE.

Figure 4: The RaspberrySTEM fits neatly on the desktop.

RDE

The RaspberrySTEM Development Environment presents a simplified user interface. The top left portion of the screen is called the Code Window. Here, you either enter the project code or copy and paste it from the tutorial. The menubar (Figure 5) has only five clickable icons. The familiar right-facing Run triangle starts the code when pressed and turns into a Stop square, which of course stops the program. While the program is running, the raspberry with stem icon on the right side of the window spins.

Figure 5: Menubar for the Code Window.

The File folder icon brings up a dialog box with a New File button and a list of all the programs you've created and saved. Each file in the list has a tiny Edit icon to its right. Clicking a program name pulls the code into the Code Window, whereas clicking on New File presents an empty screen with a single numbered line.

The Save diskette icon does not bring up a dialog box. All new files are created as Untitled.py. If you don't rename your files, you'll end up with Untitled1.py, Untitled2.py, and so on. The only way to rename a file from the RDE is to click on the File folder and then the Edit icon. The Edit dialog shows a text box with the current name of the file, where you can give it a unique name. Here, you can also Duplicate or Delete a file.

The crossed tools Settings icon lets you choose between two desktop themes and specify the file that appears in the Code Window on startup. You'll also see two buttons: one that checks for Software Updates and another that initiates a Clean Shutdown. The right-pointing double angle bracket at the far right expands the Code Window to full screen.

The short Program Output window on the bottom left shows any output your program might produce. If your program has a problem, this is also where you would see error messages.

The entire right side of the RDE is taken up by the Project & Documentation Window, which also has five icons in its menubar (Figure 6). The Forward and Back arrows move between lesson pages and hyperlinked pages within the lesson; the Home icon takes you to the Projects Guide, which lists all the projects; the API icon goes to a page that describes the program modules available for use by your programs (e.g., button, sound, GPIO, and specialized hardware modules); and the yin/yang yellow and blue snakes icon takes you to the Python (v3.2.3) documentation.

Figure 6: Menubar for the Project & Documentation Window portion of the user interface.