0x2E: DS18B20 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 enables easy interfacing of the DS18B20 temperature transmitter configured in three different ways for development and comparison of different temperature measurement strategies.

Function

This design features the popular DS18B20 temperature transmitter configured in three different ways: direct connect to a RPi GPIO, connected to a DS2482-100 I2C-OneWire bridge (single OneWire data line), and a DS2482-800 I2C-OneWire bridge (eight parallel OneWire data lines). Using, for instance, the wiringPi library, different measurement strategies can easily be developed and documented 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 0x2E 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, backside with components 

 

0x2E module mounted in a Pi Top 2

 

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

 

Bill of materials

3 pcs. decoupling capacitor, ceramic, 100 nF, 1206

3 pcs. capacitor, tantalum, 10 uF, 16 V, SMD (optional)

3 pcs. pullup resistor, 1k8, 1206

2 pcs. 4 bit DIP switch, 2.54 mm pitch

16 pcs. DS18B20 temperature transmitter, TO-92

1 pcs. DS2482-100, single I2C-OneWire bridge, SOIC-08

1 pcs. DS2482-800 octal I2C-OneWire bridge, SOIC-16

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

 

Estimated cost

Sixteen DS18B20 temperature transmitters, DIP switches, OneWire bridges, passive components, a header, and the circuit board should not cost more than EUR 20,-.

 

Downloads

Schematic PDF: 0x2E_schematic

DipTrace v. 3 schematic file: 0x2E_schematic

DipTrace v. 3 PCB design file: 0x2E_ratlined_public

Gerber files: 0x2E_Gerber

Qt 5 GUI source code: QtGUI_0x2E

 

Links

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