Solar bird
Circuit
Apparently, this circuit has been around the SGMK for quite a while, but its history is uncertain – maybe you can clarify?
The 4053 IC is a "CMOS Triple 2-Channel Analog Multiplexer/Demultiplexer with Logic-Level Conversion".
Board
The PCB, made Shenzen ready by Omega_attraktor at the 2018 kit sprint at anorg is available on kitspace.org: kitspace.org/boards/github.com/sgmk/solarbird_shenzen_rdy