The Pi-SPi Interface product line has arrived!
From Left to right: RPi 3, RS485 Interface, 8 Channel Analog Input (4-20mA, VDC and Thermistor), and 8 Channel Relay driver with 2 Relays (10 Amp Contacts) Populated.
Coming within days is the 8 channel Digital input (DC for AC Voltage input) and 2 channel Analog output (4-20mA and simultaneous VDC).
As can be seen, each module has a dual GPIO expansion port that allows as many (or as little) modules to be connected as required for a given project - and we have some pretty awesome projects lined up to share as instructables with everyone! Also, external power (typically 24 VDC) can be applied to any interface and there is no loading on the Pi's 3.3 VDC power supply. Each module has a 5V to 3.3V LDR (Low dropout regulator).
I'll share the next round of modules as soon as they're unpacked!