I created a small case for my ESP32 / NRF24L01+ setup running the awesome OpenDTU software to monitor my Hoymiles inverter.

The case was created to just fit the components I had available. It has space for a 46 mm x 59 mm circuit board (18 x 23 holes) on which the ESP32 Dev Board (30 pins) and the NRF24L01+ module with external antenna are soldered directly on using the provided 0.1" headers.

The bottom part has a bit of space for wires underneath the circuit board so the pins of ESP and radio can be connected.

NRF24L01+ pin configuration

When using the ESP32 Dev Board with 30 pins, you may have noticed that PIN16 used by the OpenDTU standard configuration is not exposed. So as shown in the picture above I used PIN15 instead.

When compiling OpenDTU you need to adapt the PIN configuration (mainly IRQ) as follows:

build_flags =
    ${env.build_flags}
    -DHOYMILES_PIN_MISO=19
    -DHOYMILES_PIN_MOSI=23
    -DHOYMILES_PIN_SCLK=18
    -DHOYMILES_PIN_IRQ=15
    -DHOYMILES_PIN_CE=4
    -DHOYMILES_PIN_CS=5

v2

I added two mounting holes suitable for M3 cylinder head screws so the ESP can be fixed without using a circuit board. The holes have a diameter of 2.5 mm and are 8 mm deep.

Printing

The print from the photos were done in PLA with 0.2 mm layer height and 15% infill.

Credits

The symbol on top is coming from the Material Design Icons Collection and the name Sól from Germanic Mythology.