Room Unit RU v02
This modul is the core component of my home automation project. The main properties are:
- based on the W5500-EVB-Pico module,
- Raspberry RP2040 dual-core Cortex M0+ microcontroller, 133Mhz clock,
- 2MByte Flash, 264kByte RAM,
- WIZnet W5500 wired Ethernet TCP/IP chip,
- 8 inputs, dry contact or 1-Wire temperature sensor, ESD-safe,
- 7 outputs, isolated, AC 240V 2A SSR (I use G3MB-202Ps, but the PCB can accept other types too, f. e. CPC1981Y),
- PCB size: 98 x 59 mm,
- 5V supply voltage.
Of course it is possible to use other Pico compatible modules, f. e. Pico W with Wifi or normal Pico without network.
Why 5V power input? Because the unit can be used together with cheap 5V POE adapters (mainly used for security cameras). POE + power supply togerher, not a bad thing, but the next generation is already in the plans with integrated POE/24VDC converters. It will be more expensive, but easier to install.
This is the V02. The V03 is on the way, the only change is that it has a slightly smaller PCB (90 x 59 mm).
The R17-R23 resistors are needed only for the CPC and similar relays (they don't have built-in current limiting resistors) and the value of them depends on the type of the relay (normally 220R-1k). For the used G3MBs they should be 0R.
The wetting current of the input contacts is ~3mA. If you don't use 1-Wire sensors you can slightly increase it, but don't overload the 3V3 regulator!
The firmware is based on the WIZnet MQTT examples. Works perfectly, together with Node-Red it is possible to build very complex systems. I will publish my version later.
