First eval PCB design

A project log for Diurnal Reef Controller for Lighting and Tides

Exactly the right lighting and tidal conditions have to occur to induce the spawning of corals (and other sea creatures).

Philip CoxPhilip Cox 06/10/2019 at 17:210 Comments

The PCB we make will control the current with 8 bits, use a PIC24F16KA controller, and a MCP7940 real time clock.

The PIC talks to the RTC over SDA & SCL lines using I2C.  Power input (P1) comes from a 36VDC LED driver that plugs into 115 VAC.  Voltage regulators down-shift the 36 V to 12V (for the cooling fan) and ultimately Vcc (which is 3.3 V).  You see all eight current control MOSFETs, and there is a single mosfet controlling the fan speed.

The diurnal curve previously shown is programed into the PIC's memory as a list of 8-bit integers (from 0 to 255 representing a normalized insolation of 0 - 1.0).  The two-sided PCB is 59mm x 47mm.

A five-pin header is provided (P2) for programming the PIC.

This should be sufficient to prove that the concept works.

Next, I intend to add an I2C flash memory to the bus.

Then add control for a blue LED (for lunar).

Then, USB ...

Then, Bluetooth, so one board can control many.