raspi adapter

KegNet Raspberry Pi Adapter Daughter Board

The adapter daughter board is a custom designed printed circuit board with soldered components for the purpose of easy hookup of the temperature sensor and flow meter to a Raspberry Pi board.

The current version is R3, which includes ports for 1 temperature sensor and 2 flow meters. R3 also includes a single LED as a ready indicator.

Images

• PCB Drawing
• Board Top
• Board Bottom
• Circuit diagram

Design

• The PCB was designed using ExpressPCB's free software on Windows
• ExpressPCB Schematic
• ExpressPCB Drawing (linked to schematic)
• There is a hole aligned specially with a hole in the Raspi to allow for a supporting brace
• The board is specially designed as slim and low as possible to fit in most existing Raspi cases
• Most components are mounted on the bottom of the board to reduce height
• R3 uses 5V power, R2 used 3.3V

Hardware

• The board connects to the Raspi's 26-pin GPIO header
• There are 3 3.5mm audio jacks used for both temperature and flow meter connections
• The flow meters require a 2.2K ohm pull-up resistor (based on 5V)
• The temperature sensor requires a 4.7K ohm pull-up resistor
• The LED requires a 180 ohm resistor
• There is also 0.1uF capacitor
• Components were sourced from Digikey and Newark