This PCB breaks out the pins in the 2x20 expansion port on the CMM2 with particular emphasis on the ports: COM1 & 2, SPI & SPI2, I2C & I2C2. Eleven individual pins are brought out to 3-pin headers (0V, 3V3, and signal) as suited to the "37 sensors" type kits. More information and links to the EagleCad gerber and .sch and .pcb files are [URL=https://www.thebackshed.com/forum/ViewTopic.php?FID=16&TID=13663]here[/URL]. That site also provides an MMBasic program which exercises most of the pins. The gerber zip file can be sent directly to JLCPCB.com. Five PCBs can be ordered for $2US--probably $10 or so with shipping.