The heart of the MashBerry is a Raspberry PI. An interface-PCB is used for connecting sensors like a PT1000, DS1820 or IR. The outputs like beeper and SSR are also connected to the interface-PCB. The PCB mainly contains a I2C-Level Shifter for connecting Hygrosens I2C-Modules (for temperature -measurement via PT1000) and the transistor drivers for the SSR and the beeper. A 4” TFT display is connected to the Raspberry’s composite output.
Minimalcircuit & diagram
For a minimal circuit only 7 external parts are needed to be connect to the Raspberry: 1 transistor, 4 resistors, 1 Solid-State relay, and one DS18B20 temperature sensor. Optionally a beeper and a IR-receiver can be connected (red dotted)
EA PCB-layout with multiple output-channels (not yet supported) and support for the Hygrosens I2C-Module can be downloaded in Target-format.