0x2F: GPIO Pi Top Module

 

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Background

The Pi Top is becoming a popular platform for software development using the Raspberry Pi singleboard computer. However, interfacing hardware to the Pi Top can be challenging, since the hub does not conform with the RPi GPIO header. This module connects simple input and output devices (LEDs, buttons, and a buzzer) to the Pi Top hub.

Function

This design breaks out GPIO connections to five LEDs, five pushbuttons with pullup resistors, and a piezo electric buzzer. Using, for instance, the wiringPi library, software access to GPIOs for demonstrating different user input and software output actions can be easily achieved with this circuit board. Graphical user interfaces can be created using Qt and wiringPi. See the download section on this page for some example source code and the Qt tutorial for getting started.

License terms
The 0x2F design is published under the Creative Commons Unported 3.0 License.  I do not profit from this design, neither should you. You are welcome to adapt, modify, and redistribute this design as long as the license terms are respected.

Physical size of PCB

84 mm (width) by 56 mm (height). Double-sided.

Rendering and photos

 

DipTrace 3D rendering, frontside with components

 

DipTrace 3D rendering, frontside, tilted, with components

 

DipTrace 3D rendering, backside with components 

 

0x2F module mounted in a Pi Top 2

 

Screen dump of Qt interface running on the Pi Top 2 (Polaris)

 

Bill of materials

5 pcs. transistor, 2N2222, NPN, SOT-23

5 pcs. LED current limiting resistor, 390R, 1206

5 pcs. pullup resistor, 10k, 1206

6 pcs. transistor base current limiting resistor, 1k, 1206

5 pcs. LED, 10 mm, through-hole, red/amber/green/white/blue

5 pcs. pushbutton, SMD

1 pcs. piezo electric buzzer

1 pcs. 1N4007 flyback diode, SMA

1 pcs. 2×17 90 degree 2.00 mm pitch male header

 

Estimated cost

Five transistors, five LEDs, five buttons, a buzzer, eleven resistors, a diode, a header, and the circuit board should not cost more than EUR 6,-.

 

Downloads

Schematic PDF: 0x2F_schematic

DipTrace v. 3 schematic file: 0x2F_schematic

DipTrace v. 3 PCB design file: 0x2F_ratlined_public

Gerber files: 0x2F_Gerber

Qt 5 GUI source code: 0x2F_QtGUI

 

Links

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